This patch teaches read-tree 3-way merge that, when only "the
other tree" changed a path, and if the index file already has
the same change, we are not in a situation that would clobber
the index and the work tree, and lets the merge succeed; this is
case #14ALT in t1000 test. It does not change the result of the
merge, but prevents it from failing when it does not have to.
Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This adds #3ALT rule (and #2ALT rule for symmetry) to the
read-tree 3-way merge logic that collapses paths that are added
only in one branch and not in the other internally.
This makes --emu23 to succeed in the last remaining case where
the pure 2-way merge succeeded and earlier one failed. Running
diff between t1001 and t1005 test scripts shows that the only
difference between the two is that --emu23 can leave the states
into separate stages so that the user can use usual 3-way merge
resolution techniques to carry forward the local changes when
pure 2-way merge would have refused to run.
Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This fixes too strong index requirement 3-way merge enforces in
one case: the same file is added in both branches.
In this case, the original code insisted that if the index file
has that path, it must match our branch and be up-to-date.
However in this particular case, it only has to match it, and
can be dirty. We just need to make sure that we keep the
work-tree copy instead of checking out the merge result.
The resolution of such a path, however, cannot be left to
outside script, because we will not keep the original stage0
entries for unmerged paths when read-tree finishes, and at that
point, the knowledge of "if we resolve it to match the new file
added in both branches, the merge succeeds and the work tree
would not lose information, but we should _not_ update the work
tree from the resulting index file" is lost. For this reason,
the now code needs to resolve this case (#5ALT) internally.
This affects some existing tests in the test suite, but all in
positive ways. In t1000 (3-way test), this #5ALT case now gets
one stage0 entry, instead of an identical stage2 and stage3
entry pair, for such a path, and one test that checked for merge
failure (because the test assumed the "stricter-than-necessary"
behaviour) does not have to fail anymore. In t1005 (emu23
test), two tests that involves a case where the work tree
already had a change introduced in the upstream (aka "merged
head"), the merge succeeds instead of failing.
Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This new flag causes two-way fast forward to internally use the
three-way merge mechanism. This behaviour is intended to offer
a better fast forward semantics when used in a dirty work tree.
The new test t1005 is parallel to the existing t1001 "pure
2-way" tests, but some parts that are commented out would fail.
These failures are due to three-way merge enforcing too strict
index requirements for cases that could succeed. This problem
will be addressed by later patches.
Without even changing three-way mechanism, the --emu23 two-way
fast forward already gives the user an easier-to-handle merge
result when a file that "merged head" updates has local
modifications. This is demonstrated as "case 16" test in t1005.
Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This is the same as "-m", but it will silently ignore any unmerged
entries, which makes it useful for efficiently forcing a new position
regardless of the state of the current index file.
IOW, to reset to a previous HEAD (in case you have had a failed
merge, for example), you'd just do
git-read-tree -u --reset HEAD
which will also update your working tree to the right state.
NOTE! The "update" will not remove files that may have been added by the
merge. Yet.
This implements the "never lose the current cache information or
the work tree state, but favor a successful merge over merge
failure" principle in the fast-forward two-tree merge operation.
It comes with a set of tests to cover all the cases described in
the case matrix found in the new documentation.
Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Looking good, but hey, it's not like I even have a real testcase for any
of this. But unlike the mess that this was yerstday, today read-cache
is pretty readable and understandable. Which is always a good sign.
Stop trying to haev this stateful thing that keeps track of what it has
seen, and use a much simpler "gather all the different stages with the
same name together and just merge them in one go" approach.
Makes it a lot more understandable, and allows the different merge
algorithms to share the basic merge loop.
This patch teaches read-tree how to use the index file locking
helpers the same way "checkout-cache -u" and "update-cache" do.
Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
That's the final one ("Yeah, sure, we believe you").
Anyway, at least the tests pass, which is not saying a lot, since they
don't end up testing all the new the things that the new merge world
order tries to do. But hopefully we're now at least not any worse off
than we were before the rewrite.
Making the main loop look more like the one- and two-way cases
introduced a bug where "src" had been updated early, but later
users hadn't been adjusted to match.
Add a "-u" flag to update the tree as a result of a merge.
Right now this code is way too anal about things, and fails merges it
shouldn't, but let me fix up the different cases and this will allow for
much smoother merging even in the presense of dirty data in the working
tree.
We don't want to overwrite state that we haven't committed yet
when merging, so it's better to make git-read-tree fail than
end up with a merge tree that ends up not having the dirty changes.
Update git-resolve-script to fail cleanly when git-read-tree fails.
Fix various things that sparse complains about:
- use NULL instead of 0
- make sure we declare everything properly, or mark it static
- use proper function declarations ("fn(void)" instead of "fn()")
Sparse is always right.
Fixes all in-code names that leaved during "big name change".
Signed-off-by: Alexey Nezhdanov <snake@penza-gsm.ru>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This allows the programs to use various simplified versions of
the SHA1 names, eg just say "HEAD" for the SHA1 pointed to by
the .git/HEAD file etc.
For example, this commit has been done with
git-commit-tree $(git-write-tree) -p HEAD
instead of the traditional "$(cat .git/HEAD)" syntax.
This patch renames read_tree_with_tree_or_commit_sha1() to
read_object_with_reference() and extends it to automatically
dereference not just "commit" objects but "tag" objects. With
this patch, you can say e.g.:
ls-tree $tag
read-tree -m $(merge-base $tag $HEAD) $tag $HEAD
diff-cache $tag
diff-tree $tag $HEAD
Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
We use that to specify alternative index files, which can be useful
if you want to (for example) generate a temporary index file to do
some specific operation that you don't want to mess with your main
one with.
It defaults to the regular ".git/index" if it hasn't been specified.
Usage string fixes to make maintenance easier (only one instance
of a string to update not multiple copies). I've spotted and
corrected inconsistent usage text in diff-tree while doing this.
Also diff-cache and read-tree usage text have been corrected to
match their up-to-date features. Earlier, neither "--cached"
form of diff-cache nor "-m single-merge" form of read-tree were
described.
Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Updates read-tree to use read_tree_with_tree_or_commit_sha1()
function. The command can take either tree or commit IDs with
this patch.
The change involves a slight modification of how it recurses down
the tree. Earlier the caller only supplied SHA1 and the recurser
read the object using it, but now it is the caller's responsibility
to read the object and give it to the recurser. This matches the
way recursive behaviour is done in other tree- related commands.
Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This cuts down the work for the "real merge" to stuff where
people might actually disagree on the algorithm. The trivial
cases would seem to be totally independent of any policy.
Normally you'd use state 0 for the "merged" state, and start out with
state 1 being "origin", state 2 being "first tree" and state 3 being
"second tree".
Once all the index entries are back in state 0, we have a successful
merge and can write the result tree back.
This allows using a git tree over NFS with different byte order, and
makes it possible to just copy a fully populated repository and have
the end result immediately usable (needing just a refresh to update
the stat information).
Now there is error() for "library" errors and die() for fatal "application"
errors. usage() is now used strictly only for usage errors.
Signed-off-by: Petr Baudis <pasky@ucw.cz>
It now requires the "--add" flag before you add any new files, and
a "--remove" file if you want to mark files for removal. And giving
it the "--refresh" flag makes it just update all the files that it
already knows about.
This is totally untested, since we can't actually _write_ things that
way yet, but I'll get to that next, I hope. That should fix the
huge wasted space for kernel-sized tree objects.
I needed this to make a "sparse" archive conversion from my old
BitKeeper tree data. The scripts to do the conversion are just
incredibly ugly, but they seem to validate the notion that you
can actually use this silly 'git' thing to save your history in.
The tool interface sucks (especially "committing" information, which is just
me doing everything by hand from the command line), but I think this is in
theory actually a viable way of describing the world. So copyright it.
