Re: How do I resolve conflict after popping stash without adding the file to index?
Jeff King p...@peff.net writes: Right, I am suggesting that latter: that stash should abort if the index has modified entries. The abort for modified working tree files is done by git-merge, which can be selective about which entries will be changed (since it knows which ones need written). I haven't thought hard enough to say whether it should be doing the same for the index (i.e., whether this is a merge problem or a stash problem). This is a stash problem. I've always thought that it insisted on having a clean index and a clean working tree, but apparently it doesn't, as shown in Dmitry's example sequence. Generally speaking, any mergy operation should be done with a clean index (i.e. matches HEAD) so that any difference between the index and the HEAD after it stops in the middle is purely the result of that mergy operation, and the commands should stop when the index is not clean as a safety measure (e.g. git am -3, git merge) [*1*]. An especially tricky command may also insist on a clean working tree if it is not easy to guarantee that it will not clobber changes by the user when it stops in the middle (e.g. git rebase). But this is an escape hatch for lazy implementations ;-) It would be ideal if a command stops without doing anything when the set of paths it needs to touch would overlap the set of paths in which user has changes before the command is run (e.g. git merge works that way). I think that stash apply requires a clean working tree for the latter reason, and does not require a clean index because it just forgot that it must do so. -- To unsubscribe from this list: send the line unsubscribe git in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: How do I resolve conflict after popping stash without adding the file to index?
On Wed, Apr 22, 2015 at 10:41:04AM -0700, Junio C Hamano wrote:
Jeff King p...@peff.net writes:
Right, I am suggesting that latter: that stash should abort if the index
has modified entries. The abort for modified working tree files is done
by git-merge, which can be selective about which entries will be changed
(since it knows which ones need written). I haven't thought hard enough
to say whether it should be doing the same for the index (i.e., whether
this is a merge problem or a stash problem).
This is a stash problem. I've always thought that it insisted on
having a clean index and a clean working tree, but apparently it
doesn't, as shown in Dmitry's example sequence.
It did check the working tree manually, until my e0e2a9c (stash: drop
dirty worktree check on apply, 2011-04-05). But I don't think we ever
checked that the index was clean with respect to HEAD.
Generally speaking, any mergy operation should be done with a clean
index (i.e. matches HEAD) so that any difference between the index
and the HEAD after it stops in the middle is purely the result of
that mergy operation, and the commands should stop when the index is
not clean as a safety measure (e.g. git am -3, git merge) [*1*].
I guess this was the heart of my question. Should a mergy operation
start with a clean index (which the caller can enforce), or does it only
need the index entries that it is going to touch to be clean (which is
known only to the merging code)? The latter is more permissive, as we
know that we will not create conflict entries that overwrite what is
staged in the index. But I don't think we have good tool support for
operating on only those entries afterwards (e.g., git reset --keep
would hose your staged changes along with undoing the parts modified by
the merge). So probably asking for a completely clean index is the only
sane thing.
An especially tricky command may also insist on a clean working tree
if it is not easy to guarantee that it will not clobber changes by
the user when it stops in the middle (e.g. git rebase). But this
is an escape hatch for lazy implementations ;-) It would be ideal if
a command stops without doing anything when the set of paths it
needs to touch would overlap the set of paths in which user has
changes before the command is run (e.g. git merge works that way).
Right, and I think we do that appropriately in stash since e0e2a9c.
I think that stash apply requires a clean working tree for the
latter reason, and does not require a clean index because it just
forgot that it must do so.
Ironically, the message before e0e2a9c actually recommends staging
changes before applying the stash, which would lead to this exact
situation! So I think the most trivial patch is:
diff --git a/git-stash.sh b/git-stash.sh
index d4cf818..f1865c9 100755
--- a/git-stash.sh
+++ b/git-stash.sh
@@ -442,6 +442,7 @@ apply_stash () {
assert_stash_like $@
git update-index -q --refresh || die $(gettext unable to refresh
index)
+ git diff-index --cached HEAD || die dirty index; cannot apply stash
# current index state
c_tree=$(git write-tree) ||
but it makes me wonder if somebody would find it annoying that they
cannot apply a stash into their work-in-progress (i.e., it _might_ cause
annoyance, but most of the time it will be convenient to do so).
We also have require_clean_work_tree() in git-sh-setup.sh. We definitely
don't want the first half of that, but we do want the diff-index check.
So probably we'd want to refactor that into two separate functions, and
only call the require_clean_index part.
-Peff
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Re: How do I resolve conflict after popping stash without adding the file to index?
On Wed, Apr 22, 2015 at 02:35:40PM -0400, Jeff King wrote:
Ironically, the message before e0e2a9c actually recommends staging
changes before applying the stash, which would lead to this exact
situation! So I think the most trivial patch is:
diff --git a/git-stash.sh b/git-stash.sh
index d4cf818..f1865c9 100755
--- a/git-stash.sh
+++ b/git-stash.sh
@@ -442,6 +442,7 @@ apply_stash () {
assert_stash_like $@
git update-index -q --refresh || die $(gettext unable to refresh
index)
+ git diff-index --cached HEAD || die dirty index; cannot apply stash
# current index state
c_tree=$(git write-tree) ||
but it makes me wonder if somebody would find it annoying that they
cannot apply a stash into their work-in-progress (i.e., it _might_ cause
annoyance, but most of the time it will be convenient to do so).
It does actually fail a test in t3903, but I think that test just
incidentally had a dirty index, and didn't care about that particular
feature.
We also have require_clean_work_tree() in git-sh-setup.sh. We definitely
don't want the first half of that, but we do want the diff-index check.
So probably we'd want to refactor that into two separate functions, and
only call the require_clean_index part.
This turned out to be more work than it was worth. Most of the effort
in that function is about adjusting the messages to handle the cases
when either or both of the working tree and index are dirty. I did pick
up the useful bits from there, though:
- use --quiet to suppress output and so that the exit code actually
matters
- use -- to disambiguate the ref
- I didn't pick up the `rev-parse HEAD` call. I don't think it's
necessary (i.e., diff-index should barf for us if it can't read
HEAD).
Here are the patches.
[1/3]: t3903: stop hard-coding commit sha1s
[2/3]: t3903: avoid applying onto dirty index
[3/3]: stash: require a clean index to apply
-Peff
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Re: How do I resolve conflict after popping stash without adding the file to index?
Jeff King p...@peff.net writes:
Ironically, the message before e0e2a9c actually recommends staging
changes before applying the stash, which would lead to this exact
situation!
The ancient history is hazy to me, but did we fall back to three-way
merge in old days (or did anything to the index for that matter), I
wonder? In a world git stash apply only applied the change to the
working tree via git apply, that old recommendation would make
perfect sense.
But obviously we do not live in such a world right now. And because
we are doing merge-recursive, we should insist on a clean index;
otherwise there is no way to undo its effect without losing the
changes by the end-user.
So I think the most trivial patch is:
diff --git a/git-stash.sh b/git-stash.sh
index d4cf818..f1865c9 100755
--- a/git-stash.sh
+++ b/git-stash.sh
@@ -442,6 +442,7 @@ apply_stash () {
assert_stash_like $@
git update-index -q --refresh || die $(gettext unable to refresh
index)
+ git diff-index --cached HEAD || die dirty index; cannot apply stash
Yes, that makes sense. The original report from Dmitry was
triggering the safety from one line above and git stash pop doing
the right thing by refusing to touch the index with unresolved mergy
operation before doing anything, and with this additional safety, we
would make it even safer from people who do git add and then git
stash pop (which is somewhat strange thing to do, given that
stash was designed for stash to save away; do other things; come
back to the original commit state that is 'reset --hard' clean;
unstash sequence in the first place).
# current index state
c_tree=$(git write-tree) ||
but it makes me wonder if somebody would find it annoying that they
cannot apply a stash into their work-in-progress (i.e., it _might_ cause
annoyance, but most of the time it will be convenient to do so).
They can always do git stash show -p stash@{n} | git apply if they
want to build changes incrementally X-, but it would be annoying.
So probably we'd want to refactor that into two separate functions, and
only call the require_clean_index part.
Hmph, but what would that helper do, other than a single diff-index
--quiet --cached HEAD call?
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Re: How do I resolve conflict after popping stash without adding the file to index?
On Wed, Apr 22, 2015 at 12:45:21PM -0700, Junio C Hamano wrote:
Jeff King p...@peff.net writes:
Ironically, the message before e0e2a9c actually recommends staging
changes before applying the stash, which would lead to this exact
situation!
The ancient history is hazy to me, but did we fall back to three-way
merge in old days (or did anything to the index for that matter), I
wonder? In a world git stash apply only applied the change to the
working tree via git apply, that old recommendation would make
perfect sense.
Hmm, that advice came in 2a79d2f (Clarify how the user can satisfy
stash's 'dirty state' check., 2008-09-29), at which point it looks like
we were already running merge-recursive. So I think it was simply bad
advice. ;)
But obviously we do not live in such a world right now. And because
we are doing merge-recursive, we should insist on a clean index;
otherwise there is no way to undo its effect without losing the
changes by the end-user.
Yeah, agreed.
but it makes me wonder if somebody would find it annoying that they
cannot apply a stash into their work-in-progress (i.e., it _might_ cause
annoyance, but most of the time it will be convenient to do so).
They can always do git stash show -p stash@{n} | git apply if they
want to build changes incrementally X-, but it would be annoying.
I think the best thing to do is introduce this safety, let it cook for a
while, and see what comes up. Perhaps we could add a --force or
similar, but I'd rather see if anybody ever actually runs into the
situation first.
So probably we'd want to refactor that into two separate functions, and
only call the require_clean_index part.
Hmph, but what would that helper do, other than a single diff-index
--quiet --cached HEAD call?
I was wanting to keep the error message and the flags we feed to
diff-index consistent. But yeah, there is little enough duplicate
material and enough added boilerplate that I do not think it is worth it
(see the series I just posted).
-Peff
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Re: How do I resolve conflict after popping stash without adding the file to index?
On 04/22/2015 12:29 AM, Jeff King wrote: Hmm, interestingly, if you do _not_ stage the changes (i.e., drop the final git add there), you get: $ git stash pop error: Your local changes to the following files would be overwritten by merge: test Please, commit your changes or stash them before you can merge. Aborting which makes sense. Writing conflict markers into the file would leave you in a situation where it is hard to recover the b content. Indeed. But we seem to skip that safety valve when the content has been staged, which seems questionable to me (technically we are slightly better off than the protected case because b was written to a git blob object, so you can recover it. But it may be difficult to find the correct blob in the object database). Any suggestions how to restore that content in the index programmatically? If it's non-trivial to do, maybe that is indeed a bug, and 'git stash pop' should abort before creating the conflict. -- To unsubscribe from this list: send the line unsubscribe git in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: How do I resolve conflict after popping stash without adding the file to index?
On Wed, Apr 22, 2015 at 01:35:05AM +0300, Dmitry Gutov wrote: But we seem to skip that safety valve when the content has been staged, which seems questionable to me (technically we are slightly better off than the protected case because b was written to a git blob object, so you can recover it. But it may be difficult to find the correct blob in the object database). Any suggestions how to restore that content in the index programmatically? If it's non-trivial to do, maybe that is indeed a bug, and 'git stash pop' should abort before creating the conflict. Right, I am suggesting that latter: that stash should abort if the index has modified entries. The abort for modified working tree files is done by git-merge, which can be selective about which entries will be changed (since it knows which ones need written). I haven't thought hard enough to say whether it should be doing the same for the index (i.e., whether this is a merge problem or a stash problem). -Peff -- To unsubscribe from this list: send the line unsubscribe git in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: How do I resolve conflict after popping stash without adding the file to index?
On Tue, Apr 21, 2015 at 01:54:56AM +0300, Dmitry Gutov wrote: I'm not really sure what higher stage entries are, but this scenario seems to be a counter-example: git init echo a test git add test git commit -m first echo aaa test git stash save echo b test git add test git stash pop Either that, or 'git stash pop' was a destructive operation, and ate the staged changes. Hmm, interestingly, if you do _not_ stage the changes (i.e., drop the final git add there), you get: $ git stash pop error: Your local changes to the following files would be overwritten by merge: test Please, commit your changes or stash them before you can merge. Aborting which makes sense. Writing conflict markers into the file would leave you in a situation where it is hard to recover the b content. But we seem to skip that safety valve when the content has been staged, which seems questionable to me (technically we are slightly better off than the protected case because b was written to a git blob object, so you can recover it. But it may be difficult to find the correct blob in the object database). -Peff -- To unsubscribe from this list: send the line unsubscribe git in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: How do I resolve conflict after popping stash without adding the file to index?
On 04/21/2015 12:11 AM, Junio C Hamano wrote: But the said file, if it had conflicted, would have had only the conflicted higher stage entries in the index, no? That is, the failed merge wouldn't have touched the index for the path if it already had changes there in the first place. I'm not really sure what higher stage entries are, but this scenario seems to be a counter-example: git init echo a test git add test git commit -m first echo aaa test git stash save echo b test git add test git stash pop Either that, or 'git stash pop' was a destructive operation, and ate the staged changes. If you want to keep them then you do not have to reset, but your question is about resolving conflict only in the working tree and leave the index clean, so I do not think git reset -- $path would not lose anything irreversibly. Rather, I'd prefer to leave the index as-is, if it makes sense. Basically, this is about tool automation, see the context here: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=20292 -- To unsubscribe from this list: send the line unsubscribe git in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: How do I resolve conflict after popping stash without adding the file to index?
Dmitry Gutov dgu...@yandex.ru writes: Either will reset already-staged changes from the said file, which is an irreversible operation. But the said file, if it had conflicted, would have had only the conflicted higher stage entries in the index, no? That is, the failed merge wouldn't have touched the index for the path if it already had changes there in the first place. If you want to keep them then you do not have to reset, but your question is about resolving conflict only in the working tree and leave the index clean, so I do not think git reset -- $path would not lose anything irreversibly. -- To unsubscribe from this list: send the line unsubscribe git in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
