# [PATCH] contrib/subtree bugfix: Can't `add` annotated tag 4 messages from 2014-05-08 to 2014-05-12. Participants: James Denholm, Junio C Hamano. Thread: https://gitlist.dev/t/36604 ## James Denholm, 2014-05-08 01:04 Subject: [PATCH] contrib/subtree bugfix: Can't `add` annotated tag Message-ID: <1399511079-1994-1-git-send-email-nod.helm@gmail.com> URL: https://gitlist.dev/e/1399511079-1994-1-git-send-email-nod.helm%40gmail.com ``` cmd_add_commit() is passed FETCH_HEAD by cmd_add_repository, which is then rev-parsed into an object ID. However, if the user is fetching a tag rather than a branch HEAD, such as by executing: $ git subtree add -P oldGit https://github.com/git/git.git tags/v1.8.0 The object ID is a tag and is never peeled, and the git commit-tree call (line 561) slaps us in the face because it doesn't handle tag IDs. Because peeling a committish ID doesn't do anything if it's already a commit, fix by peeling[1] the object ID before assigning it to $rev, as per the patch. [*1*]: Via peel_committish(), from git:git-sh-setup.sh Reported-by: Kevin Cagle Diagnosed-by: Junio C Hamano Signed-off-by: James Denholm --- NB: This bug doesn't surface when using --squash, as $rev is reassigned to the squash commit via new_squash_commit before git commit-tree sees it (though for simplicity, new_squash_commit now also sees the peeled ID). Also doesn't surface when using "git subtree merge", as git merge can handle tag objects. On a side note, if merging a tag without --squash, git merge recognises that it's a tag and adds a note to the merge commit body. It may be worth mimicking this when using "subtree merge --squash" or "subtree add". contrib/subtree/git-subtree.sh | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/contrib/subtree/git-subtree.sh b/contrib/subtree/git-subtree.sh index dc59a91..9453dae 100755 --- a/contrib/subtree/git-subtree.sh +++ b/contrib/subtree/git-subtree.sh @@ -538,7 +538,7 @@ cmd_add_commit() { revs=$(git rev-parse $default --revs-only "$@") || exit $? set -- $revs - rev="$1" + rev=$(peel_committish "$1") debug "Adding $dir as '$rev'..." git read-tree --prefix="$dir" $rev || exit $? -- 1.9.2 ``` ## Junio C Hamano, 2014-05-08 17:38 Subject: Re: [PATCH] contrib/subtree bugfix: Can't `add` annotated tag Message-ID: URL: https://gitlist.dev/e/xmqqoaz841d3.fsf%40gitster.dls.corp.google.com In-Reply-To: <1399511079-1994-1-git-send-email-nod.helm@gmail.com> ``` James Denholm writes: > cmd_add_commit() is passed FETCH_HEAD by cmd_add_repository, which is > then rev-parsed into an object ID. However, if the user is fetching a > tag rather than a branch HEAD, such as by executing: > > $ git subtree add -P oldGit https://github.com/git/git.git tags/v1.8.0 > > The object ID is a tag and is never peeled, and the git commit-tree call > (line 561) slaps us in the face because it doesn't handle tag IDs. The "rev" (not "revs") seems to be used by more things than the final commit-tree state. Are we losing some useful information by peeling it too early like this patch does? The reason why we stopped peeling when writing FETCH_HEAD was because we wanted to record the fact that we merged a tag (and use the GPG signature if found in it) when constructing the log message for the merge, and peeling the tag too early and recording the commit in FETCH_HEAD would make it impossible to do, and I am wondering if this change is making the same kind of mistake here. I see that add_msg does not use anything useful from latest_new, so with the current state of the code, it does not make that much difference (except that it says "from commit '$latest_new'", and by peeling, the fact that the user wanted to use a tag is lost from the result). > On a side note, if merging a tag without --squash, git merge recognises > that it's a tag and adds a note to the merge commit body. It may be > worth mimicking this when using "subtree merge --squash" or > "subtree add". Yes, and this change makes such a change harder to implement on top, I suspect. Would it be sufficient to do git commit-tree $tree $headp -p "$rev^0" in that "not squashing" codepath instead? > contrib/subtree/git-subtree.sh | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/contrib/subtree/git-subtree.sh b/contrib/subtree/git-subtree.sh > index dc59a91..9453dae 100755 > --- a/contrib/subtree/git-subtree.sh > +++ b/contrib/subtree/git-subtree.sh > @@ -538,7 +538,7 @@ cmd_add_commit() > { > revs=$(git rev-parse $default --revs-only "$@") || exit $? > set -- $revs > - rev="$1" > + rev=$(peel_committish "$1") > > debug "Adding $dir as '$rev'..." > git read-tree --prefix="$dir" $rev || exit $? ``` ## James Denholm, 2014-05-09 07:36 Subject: Re: [PATCH] contrib/subtree bugfix: Can't `add` annotated tag Message-ID: URL: https://gitlist.dev/e/CAHYYfeFfo%3DxVDezAGFyCvuhx%3DbkzMF6KyDCAjZNKNoGnytXDWA%40mail.gmail.com In-Reply-To: ``` Junio C Hamano wrote: > The "rev" (not "revs") seems to be used by more things than the > final commit-tree state. Are we losing some useful information by > peeling it too early like this patch does? (...) You're not wrong, actually, peeling at the last minute (or at least later) would be a better choice. I'd suggest that we aren't losing currently-useful information (as it'd be rare-if-ever that a user would look at a hash in their commit logs and think "Oh, that's that tag!"), but certainly with future development in mind it's more ideal. > I see that add_msg does not use anything useful from latest_new, so > with the current state of the code, it does not make that much > difference (except that it says "from commit '$latest_new'", and by > peeling, the fact that the user wanted to use a tag is lost from the > result). Yeah, that might be a worthy thing to porcelain-up in the future with logging the tag name rather than, or in addition to, the hash, as well as a similar change in add_squashed_msg. > Would it be sufficient to do > > git commit-tree $tree $headp -p "$rev^0" > > in that "not squashing" codepath instead? On line 561, sure. Do you want me to do a re-roll? ``` ## James Denholm, 2014-05-12 07:29 Subject: Re: [PATCH] contrib/subtree bugfix: Can't `add` annotated tag Message-ID: <20140512072947.GA18519@debian> URL: https://gitlist.dev/e/20140512072947.GA18519%40debian In-Reply-To: ``` On Fri, May 09, 2014 at 05:36:15PM +1000, James Denholm wrote: > Junio C Hamano wrote: > > Would it be sufficient to do > > > > git commit-tree $tree $headp -p "$rev^0" > > > > in that "not squashing" codepath instead? > > On line 561, sure. Do you want me to do a re-roll? Sorry to bump, but do you want a reroll on this? --- Regards, James Denholm. ```