diff options
Diffstat (limited to 'Documentation/howto')
| -rw-r--r-- | Documentation/howto/maintain-git.txt | 276 | ||||
| -rw-r--r-- | Documentation/howto/rebase-from-internal-branch.txt | 163 | ||||
| -rw-r--r-- | Documentation/howto/rebuild-from-update-hook.txt | 86 | ||||
| -rw-r--r-- | Documentation/howto/recover-corrupted-blob-object.txt | 134 | ||||
| -rw-r--r-- | Documentation/howto/revert-a-faulty-merge.txt | 269 | ||||
| -rw-r--r-- | Documentation/howto/revert-branch-rebase.txt | 187 | ||||
| -rw-r--r-- | Documentation/howto/separating-topic-branches.txt | 90 | ||||
| -rw-r--r-- | Documentation/howto/setup-git-server-over-http.txt | 277 | ||||
| -rw-r--r-- | Documentation/howto/update-hook-example.txt | 192 | ||||
| -rw-r--r-- | Documentation/howto/use-git-daemon.txt | 51 | ||||
| -rw-r--r-- | Documentation/howto/using-merge-subtree.txt | 75 |
11 files changed, 1800 insertions, 0 deletions
diff --git a/Documentation/howto/maintain-git.txt b/Documentation/howto/maintain-git.txt new file mode 100644 index 0000000000..8823a37067 --- /dev/null +++ b/Documentation/howto/maintain-git.txt @@ -0,0 +1,276 @@ +From: Junio C Hamano <gitster@pobox.com> +Date: Wed, 21 Nov 2007 16:32:55 -0800 +Subject: Addendum to "MaintNotes" +Abstract: Imagine that git development is racing along as usual, when our friendly + neighborhood maintainer is struck down by a wayward bus. Out of the + hordes of suckers (loyal developers), you have been tricked (chosen) to + step up as the new maintainer. This howto will show you "how to" do it. + +The maintainer's git time is spent on three activities. + + - Communication (60%) + + Mailing list discussions on general design, fielding user + questions, diagnosing bug reports; reviewing, commenting on, + suggesting alternatives to, and rejecting patches. + + - Integration (30%) + + Applying new patches from the contributors while spotting and + correcting minor mistakes, shuffling the integration and + testing branches, pushing the results out, cutting the + releases, and making announcements. + + - Own development (10%) + + Scratching my own itch and sending proposed patch series out. + +The policy on Integration is informally mentioned in "A Note +from the maintainer" message, which is periodically posted to +this mailing list after each feature release is made. + +The policy. + + - Feature releases are numbered as vX.Y.Z and are meant to + contain bugfixes and enhancements in any area, including + functionality, performance and usability, without regression. + + - Maintenance releases are numbered as vX.Y.Z.W and are meant + to contain only bugfixes for the corresponding vX.Y.Z feature + release and earlier maintenance releases vX.Y.Z.V (V < W). + + - 'master' branch is used to prepare for the next feature + release. In other words, at some point, the tip of 'master' + branch is tagged with vX.Y.Z. + + - 'maint' branch is used to prepare for the next maintenance + release. After the feature release vX.Y.Z is made, the tip + of 'maint' branch is set to that release, and bugfixes will + accumulate on the branch, and at some point, the tip of the + branch is tagged with vX.Y.Z.1, vX.Y.Z.2, and so on. + + - 'next' branch is used to publish changes (both enhancements + and fixes) that (1) have worthwhile goal, (2) are in a fairly + good shape suitable for everyday use, (3) but have not yet + demonstrated to be regression free. New changes are tested + in 'next' before merged to 'master'. + + - 'pu' branch is used to publish other proposed changes that do + not yet pass the criteria set for 'next'. + + - The tips of 'master', 'maint' and 'next' branches will always + fast-forward, to allow people to build their own + customization on top of them. + + - Usually 'master' contains all of 'maint', 'next' contains all + of 'master' and 'pu' contains all of 'next'. + + - The tip of 'master' is meant to be more stable than any + tagged releases, and the users are encouraged to follow it. + + - The 'next' branch is where new action takes place, and the + users are encouraged to test it so that regressions and bugs + are found before new topics are merged to 'master'. + + +A typical git day for the maintainer implements the above policy +by doing the following: + + - Scan mailing list and #git channel log. Respond with review + comments, suggestions etc. Kibitz. Collect potentially + usable patches from the mailing list. Patches about a single + topic go to one mailbox (I read my mail in Gnus, and type + \C-o to save/append messages in files in mbox format). + + - Review the patches in the saved mailboxes. Edit proposed log + message for typofixes and clarifications, and add Acks + collected from the list. Edit patch to incorporate "Oops, + that should have been like this" fixes from the discussion. + + - Classify the collected patches and handle 'master' and + 'maint' updates: + + - Obviously correct fixes that pertain to the tip of 'maint' + are directly applied to 'maint'. + + - Obviously correct fixes that pertain to the tip of 'master' + are directly applied to 'master'. + + This step is done with "git am". + + $ git checkout master ;# or "git checkout maint" + $ git am -3 -s mailbox + $ make test + + - Merge downwards (maint->master): + + $ git checkout master + $ git merge maint + $ make test + + - Review the last issue of "What's cooking" message, review the + topics scheduled for merging upwards (topic->master and + topic->maint), and merge. + + $ git checkout master ;# or "git checkout maint" + $ git merge ai/topic ;# or "git merge ai/maint-topic" + $ git log -p ORIG_HEAD.. ;# final review + $ git diff ORIG_HEAD.. ;# final review + $ make test ;# final review + $ git branch -d ai/topic ;# or "git branch -d ai/maint-topic" + + - Merge downwards (maint->master) if needed: + + $ git checkout master + $ git merge maint + $ make test + + - Merge downwards (master->next) if needed: + + $ git checkout next + $ git merge master + $ make test + + - Handle the remaining patches: + + - Anything unobvious that is applicable to 'master' (in other + words, does not depend on anything that is still in 'next' + and not in 'master') is applied to a new topic branch that + is forked from the tip of 'master'. This includes both + enhancements and unobvious fixes to 'master'. A topic + branch is named as ai/topic where "ai" is typically + author's initial and "topic" is a descriptive name of the + topic (in other words, "what's the series is about"). + + - An unobvious fix meant for 'maint' is applied to a new + topic branch that is forked from the tip of 'maint'. The + topic is named as ai/maint-topic. + + - Changes that pertain to an existing topic are applied to + the branch, but: + + - obviously correct ones are applied first; + + - questionable ones are discarded or applied to near the tip; + + - Replacement patches to an existing topic are accepted only + for commits not in 'next'. + + The above except the "replacement" are all done with: + + $ git am -3 -s mailbox + + while patch replacement is often done by: + + $ git format-patch ai/topic~$n..ai/topic ;# export existing + + then replace some parts with the new patch, and reapplying: + + $ git reset --hard ai/topic~$n + $ git am -3 -s 000*.txt + + The full test suite is always run for 'maint' and 'master' + after patch application; for topic branches the tests are run + as time permits. + + - Update "What's cooking" message to review the updates to + existing topics, newly added topics and graduated topics. + + This step is helped with Meta/cook script (where Meta/ contains + a checkout of the 'todo' branch). + + - Merge topics to 'next'. For each branch whose tip is not + merged to 'next', one of three things can happen: + + - The commits are all next-worthy; merge the topic to next: + + $ git checkout next + $ git merge ai/topic ;# or "git merge ai/maint-topic" + $ make test + + - The new parts are of mixed quality, but earlier ones are + next-worthy; merge the early parts to next: + + $ git checkout next + $ git merge ai/topic~2 ;# the tip two are dubious + $ make test + + - Nothing is next-worthy; do not do anything. + + - [** OBSOLETE **] Optionally rebase topics that do not have any commit + in next yet, when they can take advantage of low-level framework + change that is merged to 'master' already. + + $ git rebase master ai/topic + + This step is helped with Meta/git-topic.perl script to + identify which topic is rebaseable. There also is a + pre-rebase hook to make sure that topics that are already in + 'next' are not rebased beyond the merged commit. + + - [** OBSOLETE **] Rebuild "pu" to merge the tips of topics not in 'next'. + + $ git checkout pu + $ git reset --hard next + $ git merge ai/topic ;# repeat for all remaining topics + $ make test + + This step is helped with Meta/PU script + + - Push four integration branches to a private repository at + k.org and run "make test" on all of them. + + - Push four integration branches to /pub/scm/git/git.git at + k.org. This triggers its post-update hook which: + + (1) runs "git pull" in $HOME/git-doc/ repository to pull + 'master' just pushed out; + + (2) runs "make doc" in $HOME/git-doc/, install the generated + documentation in staging areas, which are separate + repositories that have html and man branches checked + out. + + (3) runs "git commit" in the staging areas, and run "git + push" back to /pub/scm/git/git.git/ to update the html + and man branches. + + (4) installs generated documentation to /pub/software/scm/git/docs/ + to be viewed from http://www.kernel.org/ + + - Fetch html and man branches back from k.org, and push four + integration branches and the two documentation branches to + repo.or.cz and other mirrors. + + +Some observations to be made. + + * Each topic is tested individually, and also together with + other topics cooking in 'next'. Until it matures, none part + of it is merged to 'master'. + + * A topic already in 'next' can get fixes while still in + 'next'. Such a topic will have many merges to 'next' (in + other words, "git log --first-parent next" will show many + "Merge ai/topic to next" for the same topic. + + * An unobvious fix for 'maint' is cooked in 'next' and then + merged to 'master' to make extra sure it is Ok and then + merged to 'maint'. + + * Even when 'next' becomes empty (in other words, all topics + prove stable and are merged to 'master' and "git diff master + next" shows empty), it has tons of merge commits that will + never be in 'master'. + + * In principle, "git log --first-parent master..next" should + show nothing but merges (in practice, there are fixup commits + and reverts that are not merges). + + * Commits near the tip of a topic branch that are not in 'next' + are fair game to be discarded, replaced or rewritten. + Commits already merged to 'next' will not be. + + * Being in the 'next' branch is not a guarantee for a topic to + be included in the next feature release. Being in the + 'master' branch typically is. diff --git a/Documentation/howto/rebase-from-internal-branch.txt b/Documentation/howto/rebase-from-internal-branch.txt new file mode 100644 index 0000000000..74a1c0c4ba --- /dev/null +++ b/Documentation/howto/rebase-from-internal-branch.txt @@ -0,0 +1,163 @@ +From: Junio C Hamano <gitster@pobox.com> +To: git@vger.kernel.org +Cc: Petr Baudis <pasky@suse.cz>, Linus Torvalds <torvalds@osdl.org> +Subject: Re: sending changesets from the middle of a git tree +Date: Sun, 14 Aug 2005 18:37:39 -0700 +Abstract: In this article, JC talks about how he rebases the + public "pu" branch using the core GIT tools when he updates + the "master" branch, and how "rebase" works. Also discussed + is how this applies to individual developers who sends patches + upstream. + +Petr Baudis <pasky@suse.cz> writes: + +> Dear diary, on Sun, Aug 14, 2005 at 09:57:13AM CEST, I got a letter +> where Junio C Hamano <junkio@cox.net> told me that... +>> Linus Torvalds <torvalds@osdl.org> writes: +>> +>> > Junio, maybe you want to talk about how you move patches from your "pu" +>> > branch to the real branches. +>> +> Actually, wouldn't this be also precisely for what StGIT is intended to? + +Exactly my feeling. I was sort of waiting for Catalin to speak +up. With its basing philosophical ancestry on quilt, this is +the kind of task StGIT is designed to do. + +I just have done a simpler one, this time using only the core +GIT tools. + +I had a handful of commits that were ahead of master in pu, and I +wanted to add some documentation bypassing my usual habit of +placing new things in pu first. At the beginning, the commit +ancestry graph looked like this: + + *"pu" head + master --> #1 --> #2 --> #3 + +So I started from master, made a bunch of edits, and committed: + + $ git checkout master + $ cd Documentation; ed git.txt ... + $ cd ..; git add Documentation/*.txt + $ git commit -s + +After the commit, the ancestry graph would look like this: + + *"pu" head + master^ --> #1 --> #2 --> #3 + \ + \---> master + +The old master is now master^ (the first parent of the master). +The new master commit holds my documentation updates. + +Now I have to deal with "pu" branch. + +This is the kind of situation I used to have all the time when +Linus was the maintainer and I was a contributor, when you look +at "master" branch being the "maintainer" branch, and "pu" +branch being the "contributor" branch. Your work started at the +tip of the "maintainer" branch some time ago, you made a lot of +progress in the meantime, and now the maintainer branch has some +other commits you do not have yet. And "git rebase" was written +with the explicit purpose of helping to maintain branches like +"pu". You _could_ merge master to pu and keep going, but if you +eventually want to cherrypick and merge some but not necessarily +all changes back to the master branch, it often makes later +operations for _you_ easier if you rebase (i.e. carry forward +your changes) "pu" rather than merge. So I ran "git rebase": + + $ git checkout pu + $ git rebase master pu + +What this does is to pick all the commits since the current +branch (note that I now am on "pu" branch) forked from the +master branch, and forward port these changes. + + master^ --> #1 --> #2 --> #3 + \ *"pu" head + \---> master --> #1' --> #2' --> #3' + +The diff between master^ and #1 is applied to master and +committed to create #1' commit with the commit information (log, +author and date) taken from commit #1. On top of that #2' and #3' +commits are made similarly out of #2 and #3 commits. + +Old #3 is not recorded in any of the .git/refs/heads/ file +anymore, so after doing this you will have dangling commit if +you ran fsck-cache, which is normal. After testing "pu", you +can run "git prune" to get rid of those original three commits. + +While I am talking about "git rebase", I should talk about how +to do cherrypicking using only the core GIT tools. + +Let's go back to the earlier picture, with different labels. + +You, as an individual developer, cloned upstream repository and +made a couple of commits on top of it. + + *your "master" head + upstream --> #1 --> #2 --> #3 + +You would want changes #2 and #3 incorporated in the upstream, +while you feel that #1 may need further improvements. So you +prepare #2 and #3 for e-mail submission. + + $ git format-patch master^^ master + +This creates two files, 0001-XXXX.patch and 0002-XXXX.patch. Send +them out "To: " your project maintainer and "Cc: " your mailing +list. You could use contributed script git-send-email if +your host has necessary perl modules for this, but your usual +MUA would do as long as it does not corrupt whitespaces in the +patch. + +Then you would wait, and you find out that the upstream picked +up your changes, along with other changes. + + where *your "master" head + upstream --> #1 --> #2 --> #3 + used \ + to be \--> #A --> #2' --> #3' --> #B --> #C + *upstream head + +The two commits #2' and #3' in the above picture record the same +changes your e-mail submission for #2 and #3 contained, but +probably with the new sign-off line added by the upstream +maintainer and definitely with different committer and ancestry +information, they are different objects from #2 and #3 commits. + +You fetch from upstream, but not merge. + + $ git fetch upstream + +This leaves the updated upstream head in .git/FETCH_HEAD but +does not touch your .git/HEAD nor .git/refs/heads/master. +You run "git rebase" now. + + $ git rebase FETCH_HEAD master + +Earlier, I said that rebase applies all the commits from your +branch on top of the upstream head. Well, I lied. "git rebase" +is a bit smarter than that and notices that #2 and #3 need not +be applied, so it only applies #1. The commit ancestry graph +becomes something like this: + + where *your old "master" head + upstream --> #1 --> #2 --> #3 + used \ your new "master" head* + to be \--> #A --> #2' --> #3' --> #B --> #C --> #1' + *upstream + head + +Again, "git prune" would discard the disused commits #1-#3 and +you continue on starting from the new "master" head, which is +the #1' commit. + +-jc + +- +To unsubscribe from this list: send the line "unsubscribe git" in +the body of a message to majordomo@vger.kernel.org +More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/Documentation/howto/rebuild-from-update-hook.txt b/Documentation/howto/rebuild-from-update-hook.txt new file mode 100644 index 0000000000..48c67568d3 --- /dev/null +++ b/Documentation/howto/rebuild-from-update-hook.txt @@ -0,0 +1,86 @@ +Subject: [HOWTO] Using post-update hook +Message-ID: <7vy86o6usx.fsf@assigned-by-dhcp.cox.net> +From: Junio C Hamano <gitster@pobox.com> +Date: Fri, 26 Aug 2005 18:19:10 -0700 +Abstract: In this how-to article, JC talks about how he + uses the post-update hook to automate git documentation page + shown at http://www.kernel.org/pub/software/scm/git/docs/. + +The pages under http://www.kernel.org/pub/software/scm/git/docs/ +are built from Documentation/ directory of the git.git project +and needed to be kept up-to-date. The www.kernel.org/ servers +are mirrored and I was told that the origin of the mirror is on +the machine $some.kernel.org, on which I was given an account +when I took over git maintainership from Linus. + +The directories relevant to this how-to are these two: + + /pub/scm/git/git.git/ The public git repository. + /pub/software/scm/git/docs/ The HTML documentation page. + +So I made a repository to generate the documentation under my +home directory over there. + + $ cd + $ mkdir doc-git && cd doc-git + $ git clone /pub/scm/git/git.git/ docgen + +What needs to happen is to update the $HOME/doc-git/docgen/ +working tree, build HTML docs there and install the result in +/pub/software/scm/git/docs/ directory. So I wrote a little +script: + + $ cat >dododoc.sh <<\EOF + #!/bin/sh + cd $HOME/doc-git/docgen || exit + + unset GIT_DIR + + git pull /pub/scm/git/git.git/ master && + cd Documentation && + make install-webdoc + EOF + +Initially I used to run this by hand whenever I push into the +public git repository. Then I did a cron job that ran twice a +day. The current round uses the post-update hook mechanism, +like this: + + $ cat >/pub/scm/git/git.git/hooks/post-update <<\EOF + #!/bin/sh + # + # An example hook script to prepare a packed repository for use over + # dumb transports. + # + # To enable this hook, make this file executable by "chmod +x post-update". + + case " $* " in + *' refs/heads/master '*) + echo $HOME/doc-git/dododoc.sh | at now + ;; + esac + exec git-update-server-info + EOF + $ chmod +x /pub/scm/git/git.git/hooks/post-update + +There are four things worth mentioning: + + - The update-hook is run after the repository accepts a "git + push", under my user privilege. It is given the full names + of refs that have been updated as arguments. My post-update + runs the dododoc.sh script only when the master head is + updated. + + - When update-hook is run, GIT_DIR is set to '.' by the calling + receive-pack. This is inherited by the dododoc.sh run via + the "at" command, and needs to be unset; otherwise, "git + pull" it does into $HOME/doc-git/docgen/ repository would not + work correctly. + + - The stdout of update hook script is not connected to git + push; I run the heavy part of the command inside "at", to + receive the execution report via e-mail. + + - This is still crude and does not protect against simultaneous + make invocations stomping on each other. I would need to add + some locking mechanism for this. diff --git a/Documentation/howto/recover-corrupted-blob-object.txt b/Documentation/howto/recover-corrupted-blob-object.txt new file mode 100644 index 0000000000..323b513ed0 --- /dev/null +++ b/Documentation/howto/recover-corrupted-blob-object.txt @@ -0,0 +1,134 @@ +Date: Fri, 9 Nov 2007 08:28:38 -0800 (PST) +From: Linus Torvalds <torvalds@linux-foundation.org> +Subject: corrupt object on git-gc +Abstract: Some tricks to reconstruct blob objects in order to fix + a corrupted repository. + +On Fri, 9 Nov 2007, Yossi Leybovich wrote: +> +> Did not help still the repository look for this object? +> Any one know how can I track this object and understand which file is it + +So exactly *because* the SHA1 hash is cryptographically secure, the hash +itself doesn't actually tell you anything, in order to fix a corrupt +object you basically have to find the "original source" for it. + +The easiest way to do that is almost always to have backups, and find the +same object somewhere else. Backups really are a good idea, and git makes +it pretty easy (if nothing else, just clone the repository somewhere else, +and make sure that you do *not* use a hard-linked clone, and preferably +not the same disk/machine). + +But since you don't seem to have backups right now, the good news is that +especially with a single blob being corrupt, these things *are* somewhat +debuggable. + +First off, move the corrupt object away, and *save* it. The most common +cause of corruption so far has been memory corruption, but even so, there +are people who would be interested in seeing the corruption - but it's +basically impossible to judge the corruption until we can also see the +original object, so right now the corrupt object is useless, but it's very +interesting for the future, in the hope that you can re-create a +non-corrupt version. + +So: + +> ib]$ mv .git/objects/4b/9458b3786228369c63936db65827de3cc06200 ../ + +This is the right thing to do, although it's usually best to save it under +it's full SHA1 name (you just dropped the "4b" from the result ;). + +Let's see what that tells us: + +> ib]$ git-fsck --full +> broken link from tree 2d9263c6d23595e7cb2a21e5ebbb53655278dff8 +> to blob 4b9458b3786228369c63936db65827de3cc06200 +> missing blob 4b9458b3786228369c63936db65827de3cc06200 + +Ok, I removed the "dangling commit" messages, because they are just +messages about the fact that you probably have rebased etc, so they're not +at all interesting. But what remains is still very useful. In particular, +we now know which tree points to it! + +Now you can do + + git ls-tree 2d9263c6d23595e7cb2a21e5ebbb53655278dff8 + +which will show something like + + 100644 blob 8d14531846b95bfa3564b58ccfb7913a034323b8 .gitignore + 100644 blob ebf9bf84da0aab5ed944264a5db2a65fe3a3e883 .mailmap + 100644 blob ca442d313d86dc67e0a2e5d584b465bd382cbf5c COPYING + 100644 blob ee909f2cc49e54f0799a4739d24c4cb9151ae453 CREDITS + 040000 tree 0f5f709c17ad89e72bdbbef6ea221c69807009f6 Documentation + 100644 blob 1570d248ad9237e4fa6e4d079336b9da62d9ba32 Kbuild + 100644 blob 1c7c229a092665b11cd46a25dbd40feeb31661d9 MAINTAINERS + ... + +and you should now have a line that looks like + + 10064 blob 4b9458b3786228369c63936db65827de3cc06200 my-magic-file + +in the output. This already tells you a *lot* it tells you what file the +corrupt blob came from! + +Now, it doesn't tell you quite enough, though: it doesn't tell what +*version* of the file didn't get correctly written! You might be really +lucky, and it may be the version that you already have checked out in your +working tree, in which case fixing this problem is really simple, just do + + git hash-object -w my-magic-file + +again, and if it outputs the missing SHA1 (4b945..) you're now all done! + +But that's the really lucky case, so let's assume that it was some older +version that was broken. How do you tell which version it was? + +The easiest way to do it is to do + + git log --raw --all --full-history -- subdirectory/my-magic-file + +and that will show you the whole log for that file (please realize that +the tree you had may not be the top-level tree, so you need to figure out +which subdirectory it was in on your own), and because you're asking for +raw output, you'll now get something like + + commit abc + Author: + Date: + .. + :100644 100644 4b9458b... newsha... M somedirectory/my-magic-file + + + commit xyz + Author: + Date: + + .. + :100644 100644 oldsha... 4b9458b... M somedirectory/my-magic-file + +and this actually tells you what the *previous* and *subsequent* versions +of that file were! So now you can look at those ("oldsha" and "newsha" +respectively), and hopefully you have done commits often, and can +re-create the missing my-magic-file version by looking at those older and +newer versions! + +If you can do that, you can now recreate the missing object with + + git hash-object -w <recreated-file> + +and your repository is good again! + +(Btw, you could have ignored the fsck, and started with doing a + + git log --raw --all + +and just looked for the sha of the missing object (4b9458b..) in that +whole thing. It's up to you - git does *have* a lot of information, it is +just missing one particular blob version. + +Trying to recreate trees and especially commits is *much* harder. So you +were lucky that it's a blob. It's quite possible that you can recreate the +thing. + + Linus diff --git a/Documentation/howto/revert-a-faulty-merge.txt b/Documentation/howto/revert-a-faulty-merge.txt new file mode 100644 index 0000000000..6fd711996a --- /dev/null +++ b/Documentation/howto/revert-a-faulty-merge.txt @@ -0,0 +1,269 @@ +Date: Fri, 19 Dec 2008 00:45:19 -0800 +From: Linus Torvalds <torvalds@linux-foundation.org>, Junio C Hamano <gitster@pobox.com> +Subject: Re: Odd merge behaviour involving reverts +Abstract: Sometimes a branch that was already merged to the mainline + is later found to be faulty. Linus and Junio give guidance on + recovering from such a premature merge and continuing development + after the offending branch is fixed. +Message-ID: <7vocz8a6zk.fsf@gitster.siamese.dyndns.org> +References: <alpine.LFD.2.00.0812181949450.14014@localhost.localdomain> + +Alan <alan@clueserver.org> said: + + I have a master branch. We have a branch off of that that some + developers are doing work on. They claim it is ready. We merge it + into the master branch. It breaks something so we revert the merge. + They make changes to the code. they get it to a point where they say + it is ok and we merge again. + + When examined, we find that code changes made before the revert are + not in the master branch, but code changes after are in the master + branch. + +and asked for help recovering from this situation. + +The history immediately after the "revert of the merge" would look like +this: + + ---o---o---o---M---x---x---W + / + ---A---B + +where A and B are on the side development that was not so good, M is the +merge that brings these premature changes into the mainline, x are changes +unrelated to what the side branch did and already made on the mainline, +and W is the "revert of the merge M" (doesn't W look M upside down?). +IOW, "diff W^..W" is similar to "diff -R M^..M". + +Such a "revert" of a merge can be made with: + + $ git revert -m 1 M + +After the developers of the side branch fix their mistakes, the history +may look like this: + + ---o---o---o---M---x---x---W---x + / + ---A---B-------------------C---D + +where C and D are to fix what was broken in A and B, and you may already +have some other changes on the mainline after W. + +If you merge the updated side branch (with D at its tip), none of the +changes made in A nor B will be in the result, because they were reverted +by W. That is what Alan saw. + +Linus explains the situation: + + Reverting a regular commit just effectively undoes what that commit + did, and is fairly straightforward. But reverting a merge commit also + undoes the _data_ that the commit changed, but it does absolutely + nothing to the effects on _history_ that the merge had. + + So the merge will still exist, and it will still be seen as joining + the two branches together, and future merges will see that merge as + the last shared state - and the revert that reverted the merge brought + in will not affect that at all. + + So a "revert" undoes the data changes, but it's very much _not_ an + "undo" in the sense that it doesn't undo the effects of a commit on + the repository history. + + So if you think of "revert" as "undo", then you're going to always + miss this part of reverts. Yes, it undoes the data, but no, it doesn't + undo history. + +In such a situation, you would want to first revert the previous revert, +which would make the history look like this: + + ---o---o---o---M---x---x---W---x---Y + / + ---A---B-------------------C---D + +where Y is the revert of W. Such a "revert of the revert" can be done +with: + + $ git revert W + +This history would (ignoring possible conflicts between what W and W..Y +changed) be equivalent to not having W nor Y at all in the history: + + ---o---o---o---M---x---x-------x---- + / + ---A---B-------------------C---D + +and merging the side branch again will not have conflict arising from an +earlier revert and revert of the revert. + + ---o---o---o---M---x---x-------x-------* + / / + ---A---B-------------------C---D + +Of course the changes made in C and D still can conflict with what was +done by any of the x, but that is just a normal merge conflict. + +On the other hand, if the developers of the side branch discarded their +faulty A and B, and redone the changes on top of the updated mainline +after the revert, the history would have looked like this: + + ---o---o---o---M---x---x---W---x---x + / \ + ---A---B A'--B'--C' + +If you reverted the revert in such a case as in the previous example: + + ---o---o---o---M---x---x---W---x---x---Y---* + / \ / + ---A---B A'--B'--C' + +where Y is the revert of W, A' and B' are rerolled A and B, and there may +also be a further fix-up C' on the side branch. "diff Y^..Y" is similar +to "diff -R W^..W" (which in turn means it is similar to "diff M^..M"), +and "diff A'^..C'" by definition would be similar but different from that, +because it is a rerolled series of the earlier change. There will be a +lot of overlapping changes that result in conflicts. So do not do "revert +of revert" blindly without thinking.. + + ---o---o---o---M---x---x---W---x---x + / \ + ---A---B A'--B'--C' + +In the history with rebased side branch, W (and M) are behind the merge +base of the updated branch and the tip of the mainline, and they should +merge without the past faulty merge and its revert getting in the way. + +To recap, these are two very different scenarios, and they want two very +different resolution strategies: + + - If the faulty side branch was fixed by adding corrections on top, then + doing a revert of the previous revert would be the right thing to do. + + - If the faulty side branch whose effects were discarded by an earlier + revert of a merge was rebuilt from scratch (i.e. rebasing and fixing, + as you seem to have interpreted), then re-merging the result without + doing anything else fancy would be the right thing to do. + (See the ADDENDUM below for how to rebuild a branch from scratch + without changing its original branching-off point.) + +However, there are things to keep in mind when reverting a merge (and +reverting such a revert). + +For example, think about what reverting a merge (and then reverting the +revert) does to bisectability. Ignore the fact that the revert of a revert +is undoing it - just think of it as a "single commit that does a lot". +Because that is what it does. + +When you have a problem you are chasing down, and you hit a "revert this +merge", what you're hitting is essentially a single commit that contains +all the changes (but obviously in reverse) of all the commits that got +merged. So it's debugging hell, because now you don't have lots of small +changes that you can try to pinpoint which _part_ of it changes. + +But does it all work? Sure it does. You can revert a merge, and from a +purely technical angle, git did it very naturally and had no real +troubles. It just considered it a change from "state before merge" to +"state after merge", and that was it. Nothing complicated, nothing odd, +nothing really dangerous. Git will do it without even thinking about it. + +So from a technical angle, there's nothing wrong with reverting a merge, +but from a workflow angle it's something that you generally should try to +avoid. + +If at all possible, for example, if you find a problem that got merged +into the main tree, rather than revert the merge, try _really_ hard to +bisect the problem down into the branch you merged, and just fix it, or +try to revert the individual commit that caused it. + +Yes, it's more complex, and no, it's not always going to work (sometimes +the answer is: "oops, I really shouldn't have merged it, because it wasn't +ready yet, and I really need to undo _all_ of the merge"). So then you +really should revert the merge, but when you want to re-do the merge, you +now need to do it by reverting the revert. + +ADDENDUM + +Sometimes you have to rewrite one of a topic branch's commits *and* you can't +change the topic's branching-off point. Consider the following situation: + + P---o---o---M---x---x---W---x + \ / + A---B---C + +where commit W reverted commit M because it turned out that commit B was wrong +and needs to be rewritten, but you need the rewritten topic to still branch +from commit P (perhaps P is a branching-off point for yet another branch, and +you want be able to merge the topic into both branches). + +The natural thing to do in this case is to checkout the A-B-C branch and use +"rebase -i P" to change commit B. However this does not rewrite commit A, +because "rebase -i" by default fast-forwards over any initial commits selected +with the "pick" command. So you end up with this: + + P---o---o---M---x---x---W---x + \ / + A---B---C <-- old branch + \ + B'---C' <-- naively rewritten branch + +To merge A-B'-C' into the mainline branch you would still have to first revert +commit W in order to pick up the changes in A, but then it's likely that the +changes in B' will conflict with the original B changes re-introduced by the +reversion of W. + +However, you can avoid these problems if you recreate the entire branch, +including commit A: + + A'---B'---C' <-- completely rewritten branch + / + P---o---o---M---x---x---W---x + \ / + A---B---C + +You can merge A'-B'-C' into the mainline branch without worrying about first +reverting W. Mainline's history would look like this: + + A'---B'---C'------------------ + / \ + P---o---o---M---x---x---W---x---M2 + \ / + A---B---C + +But if you don't actually need to change commit A, then you need some way to +recreate it as a new commit with the same changes in it. The rebase command's +--no-ff option provides a way to do this: + + $ git rebase [-i] --no-ff P + +The --no-ff option creates a new branch A'-B'-C' with all-new commits (all the +SHA IDs will be different) even if in the interactive case you only actually +modify commit B. You can then merge this new branch directly into the mainline +branch and be sure you'll get all of the branch's changes. + +You can also use --no-ff in cases where you just add extra commits to the topic +to fix it up. Let's revisit the situation discussed at the start of this howto: + + P---o---o---M---x---x---W---x + \ / + A---B---C----------------D---E <-- fixed-up topic branch + +At this point, you can use --no-ff to recreate the topic branch: + + $ git checkout E + $ git rebase --no-ff P + +yielding + + A'---B'---C'------------D'---E' <-- recreated topic branch + / + P---o---o---M---x---x---W---x + \ / + A---B---C----------------D---E + +You can merge the recreated branch into the mainline without reverting commit W, +and mainline's history will look like this: + + A'---B'---C'------------D'---E' + / \ + P---o---o---M---x---x---W---x---M2 + \ / + A---B---C diff --git a/Documentation/howto/revert-branch-rebase.txt b/Documentation/howto/revert-branch-rebase.txt new file mode 100644 index 0000000000..093c656048 --- /dev/null +++ b/Documentation/howto/revert-branch-rebase.txt @@ -0,0 +1,187 @@ +From: Junio C Hamano <gitster@pobox.com> +To: git@vger.kernel.org +Subject: [HOWTO] Reverting an existing commit +Abstract: In this article, JC gives a small real-life example of using + 'git revert' command, and using a temporary branch and tag for safety + and easier sanity checking. +Date: Mon, 29 Aug 2005 21:39:02 -0700 +Content-type: text/asciidoc +Message-ID: <7voe7g3uop.fsf@assigned-by-dhcp.cox.net> + +Reverting an existing commit +============================ + +One of the changes I pulled into the 'master' branch turns out to +break building GIT with GCC 2.95. While they were well intentioned +portability fixes, keeping things working with gcc-2.95 was also +important. Here is what I did to revert the change in the 'master' +branch and to adjust the 'pu' branch, using core GIT tools and +barebone Porcelain. + +First, prepare a throw-away branch in case I screw things up. + +------------------------------------------------ +$ git checkout -b revert-c99 master +------------------------------------------------ + +Now I am on the 'revert-c99' branch. Let's figure out which commit to +revert. I happen to know that the top of the 'master' branch is a +merge, and its second parent (i.e. foreign commit I merged from) has +the change I would want to undo. Further I happen to know that that +merge introduced 5 commits or so: + +------------------------------------------------ +$ git show-branch --more=4 master master^2 | head +* [master] Merge refs/heads/portable from http://www.cs.berkeley.... + ! [master^2] Replace C99 array initializers with code. +-- +- [master] Merge refs/heads/portable from http://www.cs.berkeley.... +*+ [master^2] Replace C99 array initializers with code. +*+ [master^2~1] Replace unsetenv() and setenv() with older putenv(). +*+ [master^2~2] Include sys/time.h in daemon.c. +*+ [master^2~3] Fix ?: statements. +*+ [master^2~4] Replace zero-length array decls with []. +* [master~1] tutorial note about git branch +------------------------------------------------ + +The '--more=4' above means "after we reach the merge base of refs, +show until we display four more common commits". That last commit +would have been where the "portable" branch was forked from the main +git.git repository, so this would show everything on both branches +since then. I just limited the output to the first handful using +'head'. + +Now I know 'master^2~4' (pronounce it as "find the second parent of +the 'master', and then go four generations back following the first +parent") is the one I would want to revert. Since I also want to say +why I am reverting it, the '-n' flag is given to 'git revert'. This +prevents it from actually making a commit, and instead 'git revert' +leaves the commit log message it wanted to use in '.msg' file: + +------------------------------------------------ +$ git revert -n master^2~4 +$ cat .msg +Revert "Replace zero-length array decls with []." + +This reverts 6c5f9baa3bc0d63e141e0afc23110205379905a4 commit. +$ git diff HEAD ;# to make sure what we are reverting makes sense. +$ make CC=gcc-2.95 clean test ;# make sure it fixed the breakage. +$ make clean test ;# make sure it did not cause other breakage. +------------------------------------------------ + +The reverted change makes sense (from reading the 'diff' output), does +fix the problem (from 'make CC=gcc-2.95' test), and does not cause new +breakage (from the last 'make test'). I'm ready to commit: + +------------------------------------------------ +$ git commit -a -s ;# read .msg into the log, + # and explain why I am reverting. +------------------------------------------------ + +I could have screwed up in any of the above steps, but in the worst +case I could just have done 'git checkout master' to start over. +Fortunately I did not have to; what I have in the current branch +'revert-c99' is what I want. So merge that back into 'master': + +------------------------------------------------ +$ git checkout master +$ git merge revert-c99 ;# this should be a fast-forward +Updating from 10d781b9caa4f71495c7b34963bef137216f86a8 to e3a693c... + cache.h | 8 ++++---- + commit.c | 2 +- + ls-files.c | 2 +- + receive-pack.c | 2 +- + server-info.c | 2 +- + 5 files changed, 8 insertions(+), 8 deletions(-) +------------------------------------------------ + +There is no need to redo the test at this point. We fast-forwarded +and we know 'master' matches 'revert-c99' exactly. In fact: + +------------------------------------------------ +$ git diff master..revert-c99 +------------------------------------------------ + +says nothing. + +Then we rebase the 'pu' branch as usual. + +------------------------------------------------ +$ git checkout pu +$ git tag pu-anchor pu +$ git rebase master +* Applying: Redo "revert" using three-way merge machinery. +First trying simple merge strategy to cherry-pick. +* Applying: Remove git-apply-patch-script. +First trying simple merge strategy to cherry-pick. +Simple cherry-pick fails; trying Automatic cherry-pick. +Removing Documentation/git-apply-patch-script.txt +Removing git-apply-patch-script +* Applying: Document "git cherry-pick" and "git revert" +First trying simple merge strategy to cherry-pick. +* Applying: mailinfo and applymbox updates +First trying simple merge strategy to cherry-pick. +* Applying: Show commits in topo order and name all commits. +First trying simple merge strategy to cherry-pick. +* Applying: More documentation updates. +First trying simple merge strategy to cherry-pick. +------------------------------------------------ + +The temporary tag 'pu-anchor' is me just being careful, in case 'git +rebase' screws up. After this, I can do these for sanity check: + +------------------------------------------------ +$ git diff pu-anchor..pu ;# make sure we got the master fix. +$ make CC=gcc-2.95 clean test ;# make sure it fixed the breakage. +$ make clean test ;# make sure it did not cause other breakage. +------------------------------------------------ + +Everything is in the good order. I do not need the temporary branch +nor tag anymore, so remove them: + +------------------------------------------------ +$ rm -f .git/refs/tags/pu-anchor +$ git branch -d revert-c99 +------------------------------------------------ + +It was an emergency fix, so we might as well merge it into the +'release candidate' branch, although I expect the next release would +be some days off: + +------------------------------------------------ +$ git checkout rc +$ git pull . master +Packing 0 objects +Unpacking 0 objects + +* committish: e3a693c... refs/heads/master from . +Trying to merge e3a693c... into 8c1f5f0... using 10d781b... +Committed merge 7fb9b7262a1d1e0a47bbfdcbbcf50ce0635d3f8f + cache.h | 8 ++++---- + commit.c | 2 +- + ls-files.c | 2 +- + receive-pack.c | 2 +- + server-info.c | 2 +- + 5 files changed, 8 insertions(+), 8 deletions(-) +------------------------------------------------ + +And the final repository status looks like this: + +------------------------------------------------ +$ git show-branch --more=1 master pu rc +! [master] Revert "Replace zero-length array decls with []." + ! [pu] git-repack: Add option to repack all objects. + * [rc] Merge refs/heads/master from . +--- + + [pu] git-repack: Add option to repack all objects. + + [pu~1] More documentation updates. + + [pu~2] Show commits in topo order and name all commits. + + [pu~3] mailinfo and applymbox updates + + [pu~4] Document "git cherry-pick" and "git revert" + + [pu~5] Remove git-apply-patch-script. + + [pu~6] Redo "revert" using three-way merge machinery. + - [rc] Merge refs/heads/master from . +++* [master] Revert "Replace zero-length array decls with []." + - [rc~1] Merge refs/heads/master from . +... [master~1] Merge refs/heads/portable from http://www.cs.berkeley.... +------------------------------------------------ diff --git a/Documentation/howto/separating-topic-branches.txt b/Documentation/howto/separating-topic-branches.txt new file mode 100644 index 0000000000..6d3eb8ed00 --- /dev/null +++ b/Documentation/howto/separating-topic-branches.txt @@ -0,0 +1,90 @@ +From: Junio C Hamano <gitster@pobox.com> +Subject: Separating topic branches +Abstract: In this article, JC describes how to separate topic branches. + +This text was originally a footnote to a discussion about the +behaviour of the git diff commands. + +Often I find myself doing that [running diff against something other +than HEAD] while rewriting messy development history. For example, I +start doing some work without knowing exactly where it leads, and end +up with a history like this: + + "master" + o---o + \ "topic" + o---o---o---o---o---o + +At this point, "topic" contains something I know I want, but it +contains two concepts that turned out to be completely independent. +And often, one topic component is larger than the other. It may +contain more than two topics. + +In order to rewrite this mess to be more manageable, I would first do +"diff master..topic", to extract the changes into a single patch, start +picking pieces from it to get logically self-contained units, and +start building on top of "master": + + $ git diff master..topic >P.diff + $ git checkout -b topicA master + ... pick and apply pieces from P.diff to build + ... commits on topicA branch. + + o---o---o + / "topicA" + o---o"master" + \ "topic" + o---o---o---o---o---o + +Before doing each commit on "topicA" HEAD, I run "diff HEAD" +before update-index the affected paths, or "diff --cached HEAD" +after. Also I would run "diff --cached master" to make sure +that the changes are only the ones related to "topicA". Usually +I do this for smaller topics first. + +After that, I'd do the remainder of the original "topic", but +for that, I do not start from the patchfile I extracted by +comparing "master" and "topic" I used initially. Still on +"topicA", I extract "diff topic", and use it to rebuild the +other topic: + + $ git diff -R topic >P.diff ;# --cached also would work fine + $ git checkout -b topicB master + ... pick and apply pieces from P.diff to build + ... commits on topicB branch. + + "topicB" + o---o---o---o---o + / + /o---o---o + |/ "topicA" + o---o"master" + \ "topic" + o---o---o---o---o---o + +After I am done, I'd try a pretend-merge between "topicA" and +"topicB" in order to make sure I have not missed anything: + + $ git pull . topicA ;# merge it into current "topicB" + $ git diff topic + "topicB" + o---o---o---o---o---* (pretend merge) + / / + /o---o---o----------' + |/ "topicA" + o---o"master" + \ "topic" + o---o---o---o---o---o + +The last diff better not to show anything other than cleanups +for crufts. Then I can finally clean things up: + + $ git branch -D topic + $ git reset --hard HEAD^ ;# nuke pretend merge + + "topicB" + o---o---o---o---o + / + /o---o---o + |/ "topicA" + o---o"master" diff --git a/Documentation/howto/setup-git-server-over-http.txt b/Documentation/howto/setup-git-server-over-http.txt new file mode 100644 index 0000000000..622ee5c8dd --- /dev/null +++ b/Documentation/howto/setup-git-server-over-http.txt @@ -0,0 +1,277 @@ +From: Rutger Nijlunsing <rutger@nospam.com> +Subject: Setting up a git repository which can be pushed into and pulled from over HTTP(S). +Date: Thu, 10 Aug 2006 22:00:26 +0200 + +Since Apache is one of those packages people like to compile +themselves while others prefer the bureaucrat's dream Debian, it is +impossible to give guidelines which will work for everyone. Just send +some feedback to the mailing list at git@vger.kernel.org to get this +document tailored to your favorite distro. + + +What's needed: + +- Have an Apache web-server + + On Debian: + $ apt-get install apache2 + To get apache2 by default started, + edit /etc/default/apache2 and set NO_START=0 + +- can edit the configuration of it. + + This could be found under /etc/httpd, or refer to your Apache documentation. + + On Debian: this means being able to edit files under /etc/apache2 + +- can restart it. + + 'apachectl --graceful' might do. If it doesn't, just stop and + restart apache. Be warning that active connections to your server + might be aborted by this. + + On Debian: + $ /etc/init.d/apache2 restart + or + $ /etc/init.d/apache2 force-reload + (which seems to do the same) + This adds symlinks from the /etc/apache2/mods-enabled to + /etc/apache2/mods-available. + +- have permissions to chown a directory + +- have git installed on the client, and + +- either have git installed on the server or have a webdav client on + the client. + +In effect, this means you're going to be root, or that you're using a +preconfigured WebDAV server. + + +Step 1: setup a bare GIT repository +----------------------------------- + +At the time of writing, git-http-push cannot remotely create a GIT +repository. So we have to do that at the server side with git. Another +option is to generate an empty bare repository at the client and copy +it to the server with a WebDAV client (which is the only option if Git +is not installed on the server). + +Create the directory under the DocumentRoot of the directories served +by Apache. As an example we take /usr/local/apache2, but try "grep +DocumentRoot /where/ever/httpd.conf" to find your root: + + $ cd /usr/local/apache/htdocs + $ mkdir my-new-repo.git + + On Debian: + + $ cd /var/www + $ mkdir my-new-repo.git + + +Initialize a bare repository + + $ cd my-new-repo.git + $ git --bare init + + +Change the ownership to your web-server's credentials. Use "grep ^User +httpd.conf" and "grep ^Group httpd.conf" to find out: + + $ chown -R www.www . + + On Debian: + + $ chown -R www-data.www-data . + + +If you do not know which user Apache runs as, you can alternatively do +a "chmod -R a+w .", inspect the files which are created later on, and +set the permissions appropriately. + +Restart apache2, and check whether http://server/my-new-repo.git gives +a directory listing. If not, check whether apache started up +successfully. + + +Step 2: enable DAV on this repository +------------------------------------- + +First make sure the dav_module is loaded. For this, insert in httpd.conf: + + LoadModule dav_module libexec/httpd/libdav.so + AddModule mod_dav.c + +Also make sure that this line exists which is the file used for +locking DAV operations: + + DAVLockDB "/usr/local/apache2/temp/DAV.lock" + + On Debian these steps can be performed with: + + Enable the dav and dav_fs modules of apache: + $ a2enmod dav_fs + (just to be sure. dav_fs might be unneeded, I don't know) + $ a2enmod dav + The DAV lock is located in /etc/apache2/mods-available/dav_fs.conf: + DAVLockDB /var/lock/apache2/DAVLock + +Of course, it can point somewhere else, but the string is actually just a +prefix in some Apache configurations, and therefore the _directory_ has to +be writable by the user Apache runs as. + +Then, add something like this to your httpd.conf + + <Location /my-new-repo.git> + DAV on + AuthType Basic + AuthName "Git" + AuthUserFile /usr/local/apache2/conf/passwd.git + Require valid-user + </Location> + + On Debian: + Create (or add to) /etc/apache2/conf.d/git.conf : + + <Location /my-new-repo.git> + DAV on + AuthType Basic + AuthName "Git" + AuthUserFile /etc/apache2/passwd.git + Require valid-user + </Location> + + Debian automatically reads all files under /etc/apache2/conf.d. + +The password file can be somewhere else, but it has to be readable by +Apache and preferably not readable by the world. + +Create this file by + $ htpasswd -c /usr/local/apache2/conf/passwd.git <user> + + On Debian: + $ htpasswd -c /etc/apache2/passwd.git <user> + +You will be asked a password, and the file is created. Subsequent calls +to htpasswd should omit the '-c' option, since you want to append to the +existing file. + +You need to restart Apache. + +Now go to http://<username>@<servername>/my-new-repo.git in your +browser to check whether it asks for a password and accepts the right +password. + +On Debian: + + To test the WebDAV part, do: + + $ apt-get install litmus + $ litmus http://<servername>/my-new-repo.git <username> <password> + + Most tests should pass. + +A command line tool to test WebDAV is cadaver. If you prefer GUIs, for +example, konqueror can open WebDAV URLs as "webdav://..." or +"webdavs://...". + +If you're into Windows, from XP onwards Internet Explorer supports +WebDAV. For this, do Internet Explorer -> Open Location -> +http://<servername>/my-new-repo.git [x] Open as webfolder -> login . + + +Step 3: setup the client +------------------------ + +Make sure that you have HTTP support, i.e. your git was built with +libcurl (version more recent than 7.10). The command 'git http-push' with +no argument should display a usage message. + +Then, add the following to your $HOME/.netrc (you can do without, but will be +asked to input your password a _lot_ of times): + + machine <servername> + login <username> + password <password> + +...and set permissions: + chmod 600 ~/.netrc + +If you want to access the web-server by its IP, you have to type that in, +instead of the server name. + +To check whether all is OK, do: + + curl --netrc --location -v http://<username>@<servername>/my-new-repo.git/HEAD + +...this should give something like 'ref: refs/heads/master', which is +the content of the file HEAD on the server. + +Now, add the remote in your existing repository which contains the project +you want to export: + + $ git-config remote.upload.url \ + http://<username>@<servername>/my-new-repo.git/ + +It is important to put the last '/'; Without it, the server will send +a redirect which git-http-push does not (yet) understand, and git-http-push +will repeat the request infinitely. + + +Step 4: make the initial push +----------------------------- + +From your client repository, do + + $ git push upload master + +This pushes branch 'master' (which is assumed to be the branch you +want to export) to repository called 'upload', which we previously +defined with git-config. + + +Using a proxy: +-------------- + +If you have to access the WebDAV server from behind an HTTP(S) proxy, +set the variable 'all_proxy' to 'http://proxy-host.com:port', or +'http://login-on-proxy:passwd-on-proxy@proxy-host.com:port'. See 'man +curl' for details. + + +Troubleshooting: +---------------- + +If git-http-push says + + Error: no DAV locking support on remote repo http://... + +then it means the web-server did not accept your authentication. Make sure +that the user name and password matches in httpd.conf, .netrc and the URL +you are uploading to. + +If git-http-push shows you an error (22/502) when trying to MOVE a blob, +it means that your web-server somehow does not recognize its name in the +request; This can happen when you start Apache, but then disable the +network interface. A simple restart of Apache helps. + +Errors like (22/502) are of format (curl error code/http error +code). So (22/404) means something like 'not found' at the server. + +Reading /usr/local/apache2/logs/error_log is often helpful. + + On Debian: Read /var/log/apache2/error.log instead. + +If you access HTTPS locations, git may fail verifying the SSL +certificate (this is return code 60). Setting http.sslVerify=false can +help diagnosing the problem, but removes security checks. + + +Debian References: http://www.debian-administration.org/articles/285 + +Authors + Johannes Schindelin <Johannes.Schindelin@gmx.de> + Rutger Nijlunsing <git@wingding.demon.nl> + Matthieu Moy <Matthieu.Moy@imag.fr> diff --git a/Documentation/howto/update-hook-example.txt b/Documentation/howto/update-hook-example.txt new file mode 100644 index 0000000000..b7f8d416d6 --- /dev/null +++ b/Documentation/howto/update-hook-example.txt @@ -0,0 +1,192 @@ +From: Junio C Hamano <gitster@pobox.com> and Carl Baldwin <cnb@fc.hp.com> +Subject: control access to branches. +Date: Thu, 17 Nov 2005 23:55:32 -0800 +Message-ID: <7vfypumlu3.fsf@assigned-by-dhcp.cox.net> +Abstract: An example hooks/update script is presented to + implement repository maintenance policies, such as who can push + into which branch and who can make a tag. + +When your developer runs git-push into the repository, +git-receive-pack is run (either locally or over ssh) as that +developer, so is hooks/update script. Quoting from the relevant +section of the documentation: + + Before each ref is updated, if $GIT_DIR/hooks/update file exists + and executable, it is called with three parameters: + + $GIT_DIR/hooks/update refname sha1-old sha1-new + + The refname parameter is relative to $GIT_DIR; e.g. for the + master head this is "refs/heads/master". Two sha1 are the + object names for the refname before and after the update. Note + that the hook is called before the refname is updated, so either + sha1-old is 0{40} (meaning there is no such ref yet), or it + should match what is recorded in refname. + +So if your policy is (1) always require fast-forward push +(i.e. never allow "git-push repo +branch:branch"), (2) you +have a list of users allowed to update each branch, and (3) you +do not let tags to be overwritten, then you can use something +like this as your hooks/update script. + +[jc: editorial note. This is a much improved version by Carl +since I posted the original outline] + +-- >8 -- beginning of script -- >8 -- + +#!/bin/bash + +umask 002 + +# If you are having trouble with this access control hook script +# you can try setting this to true. It will tell you exactly +# why a user is being allowed/denied access. + +verbose=false + +# Default shell globbing messes things up downstream +GLOBIGNORE=* + +function grant { + $verbose && echo >&2 "-Grant- $1" + echo grant + exit 0 +} + +function deny { + $verbose && echo >&2 "-Deny- $1" + echo deny + exit 1 +} + +function info { + $verbose && echo >&2 "-Info- $1" +} + +# Implement generic branch and tag policies. +# - Tags should not be updated once created. +# - Branches should only be fast-forwarded unless their pattern starts with '+' +case "$1" in + refs/tags/*) + git rev-parse --verify -q "$1" && + deny >/dev/null "You can't overwrite an existing tag" + ;; + refs/heads/*) + # No rebasing or rewinding + if expr "$2" : '0*$' >/dev/null; then + info "The branch '$1' is new..." + else + # updating -- make sure it is a fast-forward + mb=$(git-merge-base "$2" "$3") + case "$mb,$2" in + "$2,$mb") info "Update is fast-forward" ;; + *) noff=y; info "This is not a fast-forward update.";; + esac + fi + ;; + *) + deny >/dev/null \ + "Branch is not under refs/heads or refs/tags. What are you trying to do?" + ;; +esac + +# Implement per-branch controls based on username +allowed_users_file=$GIT_DIR/info/allowed-users +username=$(id -u -n) +info "The user is: '$username'" + +if test -f "$allowed_users_file" +then + rc=$(cat $allowed_users_file | grep -v '^#' | grep -v '^$' | + while read heads user_patterns + do + # does this rule apply to us? + head_pattern=${heads#+} + matchlen=$(expr "$1" : "${head_pattern#+}") + test "$matchlen" = ${#1} || continue + + # if non-ff, $heads must be with the '+' prefix + test -n "$noff" && + test "$head_pattern" = "$heads" && continue + + info "Found matching head pattern: '$head_pattern'" + for user_pattern in $user_patterns; do + info "Checking user: '$username' against pattern: '$user_pattern'" + matchlen=$(expr "$username" : "$user_pattern") + if test "$matchlen" = "${#username}" + then + grant "Allowing user: '$username' with pattern: '$user_pattern'" + fi + done + deny "The user is not in the access list for this branch" + done + ) + case "$rc" in + grant) grant >/dev/null "Granting access based on $allowed_users_file" ;; + deny) deny >/dev/null "Denying access based on $allowed_users_file" ;; + *) ;; + esac +fi + +allowed_groups_file=$GIT_DIR/info/allowed-groups +groups=$(id -G -n) +info "The user belongs to the following groups:" +info "'$groups'" + +if test -f "$allowed_groups_file" +then + rc=$(cat $allowed_groups_file | grep -v '^#' | grep -v '^$' | + while read heads group_patterns + do + # does this rule apply to us? + head_pattern=${heads#+} + matchlen=$(expr "$1" : "${head_pattern#+}") + test "$matchlen" = ${#1} || continue + + # if non-ff, $heads must be with the '+' prefix + test -n "$noff" && + test "$head_pattern" = "$heads" && continue + + info "Found matching head pattern: '$head_pattern'" + for group_pattern in $group_patterns; do + for groupname in $groups; do + info "Checking group: '$groupname' against pattern: '$group_pattern'" + matchlen=$(expr "$groupname" : "$group_pattern") + if test "$matchlen" = "${#groupname}" + then + grant "Allowing group: '$groupname' with pattern: '$group_pattern'" + fi + done + done + deny "None of the user's groups are in the access list for this branch" + done + ) + case "$rc" in + grant) grant >/dev/null "Granting access based on $allowed_groups_file" ;; + deny) deny >/dev/null "Denying access based on $allowed_groups_file" ;; + *) ;; + esac +fi + +deny >/dev/null "There are no more rules to check. Denying access" + +-- >8 -- end of script -- >8 -- + +This uses two files, $GIT_DIR/info/allowed-users and +allowed-groups, to describe which heads can be pushed into by +whom. The format of each file would look like this: + + refs/heads/master junio + +refs/heads/pu junio + refs/heads/cogito$ pasky + refs/heads/bw/.* linus + refs/heads/tmp/.* .* + refs/tags/v[0-9].* junio + +With this, Linus can push or create "bw/penguin" or "bw/zebra" +or "bw/panda" branches, Pasky can do only "cogito", and JC can +do master and pu branches and make versioned tags. And anybody +can do tmp/blah branches. The '+' sign at the pu record means +that JC can make non-fast-forward pushes on it. + +------------ diff --git a/Documentation/howto/use-git-daemon.txt b/Documentation/howto/use-git-daemon.txt new file mode 100644 index 0000000000..4e2f75cb61 --- /dev/null +++ b/Documentation/howto/use-git-daemon.txt @@ -0,0 +1,51 @@ +How to use git-daemon + +Git can be run in inetd mode and in stand alone mode. But all you want is +let a coworker pull from you, and therefore need to set up a git server +real quick, right? + +Note that git-daemon is not really chatty at the moment, especially when +things do not go according to plan (e.g. a socket could not be bound). + +Another word of warning: if you run + + $ git ls-remote git://127.0.0.1/rule-the-world.git + +and you see a message like + + fatal: The remote end hung up unexpectedly + +it only means that _something_ went wrong. To find out _what_ went wrong, +you have to ask the server. (Git refuses to be more precise for your +security only. Take off your shoes now. You have any coins in your pockets? +Sorry, not allowed -- who knows what you planned to do with them?) + +With these two caveats, let's see an example: + + $ git daemon --reuseaddr --verbose --base-path=/home/gitte/git \ + --export-all -- /home/gitte/git/rule-the-world.git + +(Of course, unless your user name is `gitte` _and_ your repository is in +~/rule-the-world.git, you have to adjust the paths. If your repository is +not bare, be aware that you have to type the path to the .git directory!) + +This invocation tries to reuse the address if it is already taken +(this can save you some debugging, because otherwise killing and restarting +git-daemon could just silently fail to bind to a socket). + +Also, it is (relatively) verbose when somebody actually connects to it. +It also sets the base path, which means that all the projects which can be +accessed using this daemon have to reside in or under that path. + +The option `--export-all` just means that you _don't_ have to create a +file named `git-daemon-export-ok` in each exported repository. (Otherwise, +git-daemon would complain loudly, and refuse to cooperate.) + +Last of all, the repository which should be exported is specified. It is +a good practice to put the paths after a "--" separator. + +Now, test your daemon with + + $ git ls-remote git://127.0.0.1/rule-the-world.git + +If this does not work, find out why, and submit a patch to this document. diff --git a/Documentation/howto/using-merge-subtree.txt b/Documentation/howto/using-merge-subtree.txt new file mode 100644 index 0000000000..2933056120 --- /dev/null +++ b/Documentation/howto/using-merge-subtree.txt @@ -0,0 +1,75 @@ +Date: Sat, 5 Jan 2008 20:17:40 -0500 +From: Sean <seanlkml@sympatico.ca> +To: Miklos Vajna <vmiklos@frugalware.org> +Cc: git@vger.kernel.org +Subject: how to use git merge -s subtree? +Abstract: In this article, Sean demonstrates how one can use the subtree merge + strategy. +Content-type: text/asciidoc +Message-ID: <BAYC1-PASMTP12374B54BA370A1E1C6E78AE4E0@CEZ.ICE> + +How to use the subtree merge strategy +===================================== + +There are situations where you want to include contents in your project +from an independently developed project. You can just pull from the +other project as long as there are no conflicting paths. + +The problematic case is when there are conflicting files. Potential +candidates are Makefiles and other standard filenames. You could merge +these files but probably you do not want to. A better solution for this +problem can be to merge the project as its own subdirectory. This is not +supported by the 'recursive' merge strategy, so just pulling won't work. + +What you want is the 'subtree' merge strategy, which helps you in such a +situation. + +In this example, let's say you have the repository at `/path/to/B` (but +it can be an URL as well, if you want). You want to merge the 'master' +branch of that repository to the `dir-B` subdirectory in your current +branch. + +Here is the command sequence you need: + +---------------- +$ git remote add -f Bproject /path/to/B <1> +$ git merge -s ours --no-commit Bproject/master <2> +$ git read-tree --prefix=dir-B/ -u Bproject/master <3> +$ git commit -m "Merge B project as our subdirectory" <4> + +$ git pull -s subtree Bproject master <5> +---------------- +<1> name the other project "Bproject", and fetch. +<2> prepare for the later step to record the result as a merge. +<3> read "master" branch of Bproject to the subdirectory "dir-B". +<4> record the merge result. +<5> maintain the result with subsequent merges using "subtree" + +The first four commands are used for the initial merge, while the last +one is to merge updates from 'B project'. + +Comparing 'subtree' merge with submodules +----------------------------------------- + +- The benefit of using subtree merge is that it requires less + administrative burden from the users of your repository. It works with + older (before Git v1.5.2) clients and you have the code right after + clone. + +- However if you use submodules then you can choose not to transfer the + submodule objects. This may be a problem with the subtree merge. + +- Also, in case you make changes to the other project, it is easier to + submit changes if you just use submodules. + +Additional tips +--------------- + +- If you made changes to the other project in your repository, they may + want to merge from your project. This is possible using subtree -- it + can shift up the paths in your tree and then they can merge only the + relevant parts of your tree. + +- Please note that if the other project merges from you, then it will + connect its history to yours, which can be something they don't want + to. |