diff options
Diffstat (limited to 'Documentation/howto')
| -rw-r--r-- | Documentation/howto/maintain-git.txt | 2 | ||||
| -rw-r--r-- | Documentation/howto/rebase-and-edit.txt | 79 | ||||
| -rw-r--r-- | Documentation/howto/rebase-from-internal-branch.txt | 4 | ||||
| -rw-r--r-- | Documentation/howto/rebuild-from-update-hook.txt | 2 | ||||
| -rw-r--r-- | Documentation/howto/revert-a-faulty-merge.txt | 179 | ||||
| -rw-r--r-- | Documentation/howto/revert-branch-rebase.txt | 6 | ||||
| -rw-r--r-- | Documentation/howto/separating-topic-branches.txt | 2 | ||||
| -rw-r--r-- | Documentation/howto/setup-git-server-over-http.txt | 4 | ||||
| -rw-r--r-- | Documentation/howto/update-hook-example.txt | 92 |
9 files changed, 245 insertions, 125 deletions
diff --git a/Documentation/howto/maintain-git.txt b/Documentation/howto/maintain-git.txt index 4357e26913..d527b30770 100644 --- a/Documentation/howto/maintain-git.txt +++ b/Documentation/howto/maintain-git.txt @@ -59,7 +59,7 @@ The policy. 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 + fast-forward, to allow people to build their own customization on top of them. - Usually 'master' contains all of 'maint', 'next' contains all diff --git a/Documentation/howto/rebase-and-edit.txt b/Documentation/howto/rebase-and-edit.txt deleted file mode 100644 index 554909fe08..0000000000 --- a/Documentation/howto/rebase-and-edit.txt +++ /dev/null @@ -1,79 +0,0 @@ -Date: Sat, 13 Aug 2005 22:16:02 -0700 (PDT) -From: Linus Torvalds <torvalds@osdl.org> -To: Steve French <smfrench@austin.rr.com> -cc: git@vger.kernel.org -Subject: Re: sending changesets from the middle of a git tree -Abstract: In this article, Linus demonstrates how a broken commit - in a sequence of commits can be removed by rewinding the head and - reapplying selected changes. - -On Sat, 13 Aug 2005, Linus Torvalds wrote: - -> That's correct. Same things apply: you can move a patch over, and create a -> new one with a modified comment, but basically the _old_ commit will be -> immutable. - -Let me clarify. - -You can entirely _drop_ old branches, so commits may be immutable, but -nothing forces you to keep them. Of course, when you drop a commit, you'll -always end up dropping all the commits that depended on it, and if you -actually got somebody else to pull that commit you can't drop it from -_their_ repository, but undoing things is not impossible. - -For example, let's say that you've made a mess of things: you've committed -three commits "old->a->b->c", and you notice that "a" was broken, but you -want to save "b" and "c". What you can do is - - # Create a branch "broken" that is the current code - # for reference - git branch broken - - # Reset the main branch to three parents back: this - # effectively undoes the three top commits - git reset HEAD^^^ - git checkout -f - - # Check the result visually to make sure you know what's - # going on - gitk --all - - # Re-apply the two top ones from "broken" - # - # First "parent of broken" (aka b): - git-diff-tree -p broken^ | git-apply --index - git commit --reedit=broken^ - - # Then "top of broken" (aka c): - git-diff-tree -p broken | git-apply --index - git commit --reedit=broken - -and you've now re-applied (and possibly edited the comments) the two -commits b/c, and commit "a" is basically gone (it still exists in the -"broken" branch, of course). - -Finally, check out the end result again: - - # Look at the new commit history - gitk --all - -to see that everything looks sensible. - -And then, you can just remove the broken branch if you decide you really -don't want it: - - # remove 'broken' branch - git branch -d broken - - # Prune old objects if you're really really sure - git prune - -And yeah, I'm sure there are other ways of doing this. And as usual, the -above is totally untested, and I just wrote it down in this email, so if -I've done something wrong, you'll have to figure it out on your own ;) - - Linus -- -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/rebase-from-internal-branch.txt b/Documentation/howto/rebase-from-internal-branch.txt index 7a76045eb7..74a1c0c4ba 100644 --- a/Documentation/howto/rebase-from-internal-branch.txt +++ b/Documentation/howto/rebase-from-internal-branch.txt @@ -1,4 +1,4 @@ -From: Junio C Hamano <junkio@cox.net> +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 @@ -27,7 +27,7 @@ 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 commits that were ahead of master in pu, and I +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: diff --git a/Documentation/howto/rebuild-from-update-hook.txt b/Documentation/howto/rebuild-from-update-hook.txt index 8d55dfbfae..48c67568d3 100644 --- a/Documentation/howto/rebuild-from-update-hook.txt +++ b/Documentation/howto/rebuild-from-update-hook.txt @@ -1,6 +1,6 @@ Subject: [HOWTO] Using post-update hook Message-ID: <7vy86o6usx.fsf@assigned-by-dhcp.cox.net> -From: Junio C Hamano <junkio@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 diff --git a/Documentation/howto/revert-a-faulty-merge.txt b/Documentation/howto/revert-a-faulty-merge.txt new file mode 100644 index 0000000000..3b4a390005 --- /dev/null +++ b/Documentation/howto/revert-a-faulty-merge.txt @@ -0,0 +1,179 @@ +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. + +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. diff --git a/Documentation/howto/revert-branch-rebase.txt b/Documentation/howto/revert-branch-rebase.txt index 865a666324..8c32da6deb 100644 --- a/Documentation/howto/revert-branch-rebase.txt +++ b/Documentation/howto/revert-branch-rebase.txt @@ -1,4 +1,4 @@ -From: Junio C Hamano <junkio@cox.net> +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 @@ -85,7 +85,7 @@ Fortunately I did not have to; what I have in the current branch ------------------------------------------------ $ git checkout master -$ git merge revert-c99 ;# this should be a fast forward +$ git merge revert-c99 ;# this should be a fast-forward Updating from 10d781b9caa4f71495c7b34963bef137216f86a8 to e3a693c... cache.h | 8 ++++---- commit.c | 2 +- @@ -95,7 +95,7 @@ Updating from 10d781b9caa4f71495c7b34963bef137216f86a8 to e3a693c... 5 files changed, 8 insertions(+), 8 deletions(-) ------------------------------------------------ -There is no need to redo the test at this point. We fast forwarded +There is no need to redo the test at this point. We fast-forwarded and we know 'master' matches 'revert-c99' exactly. In fact: ------------------------------------------------ diff --git a/Documentation/howto/separating-topic-branches.txt b/Documentation/howto/separating-topic-branches.txt index 0d73b31224..6d3eb8ed00 100644 --- a/Documentation/howto/separating-topic-branches.txt +++ b/Documentation/howto/separating-topic-branches.txt @@ -1,4 +1,4 @@ -From: Junio C Hamano <junkio@cox.net> +From: Junio C Hamano <gitster@pobox.com> Subject: Separating topic branches Abstract: In this article, JC describes how to separate topic branches. diff --git a/Documentation/howto/setup-git-server-over-http.txt b/Documentation/howto/setup-git-server-over-http.txt index b7d09c1ec6..622ee5c8dd 100644 --- a/Documentation/howto/setup-git-server-over-http.txt +++ b/Documentation/howto/setup-git-server-over-http.txt @@ -143,7 +143,7 @@ Then, add something like this to your httpd.conf Require valid-user </Location> - Debian automatically reads all files under /etc/apach2/conf.d. + 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. @@ -186,7 +186,7 @@ Step 3: setup the client ------------------------ Make sure that you have HTTP support, i.e. your git was built with -curl (version more recent than 7.10). The command 'git http-push' 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 diff --git a/Documentation/howto/update-hook-example.txt b/Documentation/howto/update-hook-example.txt index 88765b5575..b7f8d416d6 100644 --- a/Documentation/howto/update-hook-example.txt +++ b/Documentation/howto/update-hook-example.txt @@ -1,4 +1,4 @@ -From: Junio C Hamano <junkio@cox.net> and Carl Baldwin <cnb@fc.hp.com> +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> @@ -65,10 +65,10 @@ function info { # Implement generic branch and tag policies. # - Tags should not be updated once created. -# - Branches should only be fast-forwarded. +# - Branches should only be fast-forwarded unless their pattern starts with '+' case "$1" in refs/tags/*) - [ -f "$GIT_DIR/$1" ] && + git rev-parse --verify -q "$1" && deny >/dev/null "You can't overwrite an existing tag" ;; refs/heads/*) @@ -76,11 +76,11 @@ case "$1" in if expr "$2" : '0*$' >/dev/null; then info "The branch '$1' is new..." else - # updating -- make sure it is a fast forward + # updating -- make sure it is a fast-forward mb=$(git-merge-base "$2" "$3") case "$mb,$2" in "$2,$mb") info "Update is fast-forward" ;; - *) deny >/dev/null "This is not a fast-forward update." ;; + *) noff=y; info "This is not a fast-forward update.";; esac fi ;; @@ -95,21 +95,30 @@ allowed_users_file=$GIT_DIR/info/allowed-users username=$(id -u -n) info "The user is: '$username'" -if [ -f "$allowed_users_file" ]; then +if test -f "$allowed_users_file" +then rc=$(cat $allowed_users_file | grep -v '^#' | grep -v '^$' | - while read head_pattern user_patterns; do - matchlen=$(expr "$1" : "$head_pattern") - if [ "$matchlen" == "${#1}" ]; then - 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 [ "$matchlen" == "${#username}" ]; then - grant "Allowing user: '$username' with pattern: '$user_pattern'" - fi - done - deny "The user is not in the access list for this branch" - fi + 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 "$rc" in @@ -124,23 +133,32 @@ groups=$(id -G -n) info "The user belongs to the following groups:" info "'$groups'" -if [ -f "$allowed_groups_file" ]; then +if test -f "$allowed_groups_file" +then rc=$(cat $allowed_groups_file | grep -v '^#' | grep -v '^$' | - while read head_pattern group_patterns; do - matchlen=$(expr "$1" : "$head_pattern") - if [ "$matchlen" == "${#1}" ]; then - 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 [ "$matchlen" == "${#groupname}" ]; then - grant "Allowing group: '$groupname' with pattern: '$group_pattern'" - fi - done + 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 - deny "None of the user's groups are in the access list for this branch" - fi + done + deny "None of the user's groups are in the access list for this branch" done ) case "$rc" in @@ -159,6 +177,7 @@ allowed-groups, to describe which heads can be pushed into by whom. The format of each file would look like this: refs/heads/master junio + +refs/heads/pu junio refs/heads/cogito$ pasky refs/heads/bw/.* linus refs/heads/tmp/.* .* @@ -166,7 +185,8 @@ whom. The format of each file would look like this: 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 branch and make versioned tags. And anybody can do -tmp/blah branches. +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. ------------ |