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| -rw-r--r-- | Documentation/user-manual.txt | 73 |
1 files changed, 40 insertions, 33 deletions
diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index d353d08c92..03206c5344 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -1402,12 +1402,11 @@ differently. Normally, a merge results in a merge commit, with two parents, one pointing at each of the two lines of development that were merged. -However, if one of the two lines of development is completely -contained within the other--so every commit present in the one is -already contained in the other--then git just performs a -<<fast-forwards,fast forward>>; the head of the current branch is -moved forward to point at the head of the merged-in branch, without -any new commits being created. +However, if the current branch is a descendant of the other--so every +commit present in the one is already contained in the other--then git +just performs a "fast forward"; the head of the current branch is moved +forward to point at the head of the merged-in branch, without any new +commits being created. [[fixing-mistakes]] Fixing mistakes @@ -1559,8 +1558,10 @@ dangling tree b24c2473f1fd3d91352a624795be026d64c8841f ... ------------------------------------------------- -Dangling objects are objects that are harmless, but also unnecessary; -you can remove them at any time with gitlink:git-prune[1] or the --prune +Dangling objects are not a problem. At worst they may take up a little +extra disk space. They can sometimes provide a last-resort method of +recovery lost work--see <<dangling-objects>> for details. However, if +you want, you may remove them with gitlink:git-prune[1] or the --prune option to gitlink:git-gc[1]: ------------------------------------------------- @@ -1571,9 +1572,6 @@ This may be time-consuming. Unlike most other git operations (including git-gc when run without any options), it is not safe to prune while other git operations are in progress in the same repository. -For more about dangling objects, see <<dangling-objects>>. - - [[recovering-lost-changes]] Recovering lost changes ~~~~~~~~~~~~~~~~~~~~~~~ @@ -1626,16 +1624,16 @@ While normal history is shared by every repository that works on the same project, the reflog history is not shared: it tells you only about how the branches in your local repository have changed over time. -[[dangling-objects]] +[[dangling-object-recovery]] Examining dangling objects ^^^^^^^^^^^^^^^^^^^^^^^^^^ -In some situations the reflog may not be able to save you. For -example, suppose you delete a branch, then realize you need the history -it contained. The reflog is also deleted; however, if you have not -yet pruned the repository, then you may still be able to find -the lost commits; run git-fsck and watch for output that mentions -"dangling commits": +In some situations the reflog may not be able to save you. For example, +suppose you delete a branch, then realize you need the history it +contained. The reflog is also deleted; however, if you have not yet +pruned the repository, then you may still be able to find the lost +commits in the dangling objects that git-fsck reports. See +<<dangling-objects>> for the details. ------------------------------------------------- $ git fsck @@ -1667,6 +1665,9 @@ reference pointing to it, for example, a new branch: $ git branch recovered-branch 7281251ddd ------------------------------------------------ +Other types of dangling objects (blobs and trees) are also possible, and +dangling objects can arise in other situations. + [[sharing-development]] Sharing development with others @@ -2260,18 +2261,18 @@ $ git fetch git://example.com/proj.git master:example-master will create a new branch named "example-master" and store in it the branch named "master" from the repository at the given URL. If you already have a branch named example-master, it will attempt to -"fast-forward" to the commit given by example.com's master branch. So -next we explain what a fast-forward is: +<<fast-forwards,fast-forward>> to the commit given by example.com's +master branch. In more detail: -[[fast-forwards-2]] -Understanding git history: fast-forwards ----------------------------------------- +[[fetch-fast-forwards]] +git fetch and fast-forwards +--------------------------- In the previous example, when updating an existing branch, "git fetch" checks to make sure that the most recent commit on the remote branch is a descendant of the most recent commit on your copy of the branch before updating your copy of the branch to point at the new -commit. Git calls this process a "fast forward". +commit. Git calls this process a <<fast-forwards,fast forward>>. A fast forward looks something like this: @@ -3062,7 +3063,7 @@ objects will work exactly as they did before. The gitlink:git-gc[1] command performs packing, pruning, and more for you, so is normally the only high-level command you need. -[[dangling-objects-2]] +[[dangling-objects]] Dangling objects ---------------- @@ -3072,11 +3073,10 @@ objects. They are not a problem. The most common cause of dangling objects is that you've rebased a branch, or you have pulled from somebody else who rebased a branch--see <<cleaning-up-history>>. In that case, the old head of the original -branch still exists, as does obviously everything it pointed to. The -branch pointer itself just doesn't, since you replaced it with another -one. +branch still exists, as does everything it pointed to. The branch +pointer itself just doesn't, since you replaced it with another one. -There are also other situations too that cause dangling objects. For +There are also other situations that cause dangling objects. For example, a "dangling blob" may arise because you did a "git add" of a file, but then, before you actually committed it and made it part of the bigger picture, you changed something else in that file and committed @@ -3098,15 +3098,22 @@ be how you recover your old tree (say, you did a rebase, and realized that you really didn't want to - you can look at what dangling objects you have, and decide to reset your head to some old dangling state). -For commits, the most useful thing to do with dangling objects tends to -be to do a simple +For commits, you can just use: ------------------------------------------------ $ gitk <dangling-commit-sha-goes-here> --not --all ------------------------------------------------ -For blobs and trees, you can't do the same, but you can examine them. -You can just do +This asks for all the history reachable from the given commit but not +from any branch, tag, or other reference. If you decide it's something +you want, you can always create a new reference to it, e.g., + +------------------------------------------------ +$ git branch recovered-branch <dangling-commit-sha-goes-here> +------------------------------------------------ + +For blobs and trees, you can't do the same, but you can still examine +them. You can just do ------------------------------------------------ $ git show <dangling-blob/tree-sha-goes-here> |