Excellent, I have done a rebase, so that could certainly be it. I'll
take a look at the contents using the suggestions you provided.
Thanks for the enlightenment. :-)
Larry.
Linus Torvalds wrote:
quoted text > [ Maybe this should be a FAQ answer in some git documentation? Feel free
> to edit up this email and use it as a base.. ]
>
> On Thu, 25 Jan 2007, Larry Streepy wrote:
>
>
>> Sorry to ask such a basic question, but I can't quite decipher the output of
>> fsck-objects. When I run it, I get this:
>>
>> git fsck-objects
>> dangling commit 2213f6d4dd39ca8baebd0427723723e63208521b
>> dangling commit f0d4e00196bd5ee54463e9ea7a0f0e8303da767f
>> dangling blob 6a6d0b01b3e96d49a8f2c7addd4ef8c3bd1f5761
>>
>>
>> Even after a "repack -a -d" they still exist. The man page has a short
>> explanation, but, at least for me, it wasn't fully enlightening. :-)
>>
>> The man page says that dangling commits could be "root" commits, but since my
>> repo started as a clone of another repo, I don't see how I could have any root
>> commits. Also, the page doesn't really describe what a dangling blob is.
>>
>> So, can someone explain what these artifacts are and if they are a problem
>> that I should be worried about?
>>
>
> The most common situation is that you've rebased a branch (or you have
> pulled from somebody else who rebased a branch, like the "pu" branch in
> the git.git archive itself).
>
> What happens is that 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.
>
> However, there are certainly other situations too that cause dangling
> objects. For example, the "dangling blob" situation you have tends to be
> 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 that *updated* thing - the old state that
> you added originally ends up not being pointed to by any commit/tree, so
> it's now a dangling blob object.
>
> Similarly, when the "recursive" merge strategy runs, and finds that there
> are criss-cross merges and thus more than one merge base (which is fairly
> unusual, but it does happen), it will generate one temporary midway tree
> (or possibly even more, if you had lots of criss-crossing merges and
> more than two merge bases) as a temporary internal merge base, and again,
> those are real objects, but the end result will not end up pointing to
> them, so they end up "dangling" in your repository.
>
> Generally, dangling objects aren't anything to worry about. They can even
> be very useful: if you screw something up, the dangling objects can 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
>
> gitk <dangling-commit-sha-goes-here> --not --all
>
> which means exactly what it sounds like: it says that you want to see the
> commit history that is described by the dangling commit(s), but you do NOT
> want to see the history that is described by all your branches and tags
> (which are the things you normally reach). That basically shows you in a
> nice way what the danglign commit was (and notice that it might not be
> just one commit: we only report the "tip of the line" as being dangling,
> but there might be a whole deep and complex commit history that has gotten
> dropped - rebasing will do that).
>
> For blobs and trees, you can't do the same, but you can examine them. You
> can just do
>
> git show <dangling-blob/tree-sha-goes-here>
>
> to show what the contents of the blob were (or, for a tree, basically what
> the "ls" for that directory was), and that may give you some idea of what
> the operation was that left that dangling object.
>
> Usually, dangling blobs and trees aren't very interesting. They're almost
> always the result of either being a half-way mergebase (the blob will
> often even have the conflict markers from a merge in it, if you have had
> conflicting merges that you fixed up by hand), or simply because you
> interrupted a "git fetch" with ^C or something like that, leaving _some_
> of the new objects in the object database, but just dangling and useless.
>
> Anyway, once you are sure that you're not interested in any dangling
> state, you can just prune all unreachable objects:
>
> git prune
>
> and they'll be gone. But you should only run "git prune" on a quiescent
> repository - it's kind of like doing a filesystem fsck recovery: you don't
> want to do that while the filesystem is mounted.
>
> (The same is true of "git-fsck-objects" itself, btw - but since
> git-fsck-objects never actually *changes* the repository, it just reports
> on what it found, git-fsck-objects itself is never "dangerous" to run.
> Running it while somebody is actually changing the repository can cause
> confusing and scary messages, but it won't actually do anything bad. In
> contrast, running "git prune" while somebody is actively changing the
> repository is a *BAD* idea).
>
> Linus
>
