The automatic tree-matching in "git merge -s subtree" was broken 5
years ago and nobody has noticed since then, which is now fixed.
* jk/merge-subtree-heuristics:
score_trees(): fix iteration over trees with missing entries
In score_trees(), we walk over two sorted trees to find
which entries are missing or have different content between
the two. So if we have two trees with these entries:
one two
--- ---
a a
b c
c d
we'd expect the loop to:
- compare "a" to "a"
- compare "b" to "c"; because these are sorted lists, we
know that the second tree does not have "b"
- compare "c" to "c"
- compare "d" to end-of-list; we know that the first tree
does not have "d"
And prior to d8febde370 (match-trees: simplify score_trees()
using tree_entry(), 2013-03-24) that worked. But after that
commit, we mistakenly increment the tree pointers for every
loop iteration, even when we've processed the entry for only
one side. As a result, we end up doing this:
- compare "a" to "a"
- compare "b" to "c"; we know that we do not have "b", but
we still increment both tree pointers; at this point
we're out of sync and all further comparisons are wrong
- compare "c" to "d" and mistakenly claim that the second
tree does not have "c"
- exit the loop, mistakenly not realizing that the first
tree does not have "d"
So contrary to the claim in d8febde370, we really do need to
manually use update_tree_entry(), because advancing the tree
pointer depends on the entry comparison.
That means we must stop using tree_entry() to access each
entry, since it auto-advances the pointer. Instead:
- we'll use tree_desc.size directly to know if there's
anything left to look at (which is what tree_entry() was
doing under the hood)
- rather than do an extra struct assignment to "e1" and
"e2", we can just access the "entry" field of tree_desc
directly
That makes us a little more intimate with the tree_desc
code, but that's not uncommon for its callers.
The included test shows off the bug by adding a new entry
"bar.t", which sorts early in the tree and de-syncs the
comparison for "foo.t", which comes after.
Reported-by: George Shammas <georgyo@gmail.com>
Helped-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This should make these functions easier to find and cache.h less
overwhelming to read.
In particular, this moves:
- read_object_file
- oid_object_info
- write_object_file
As a result, most of the codebase needs to #include object-store.h.
In this patch the #include is only added to files that would fail to
compile otherwise. It would be better to #include wherever
identifiers from the header are used. That can happen later
when we have better tooling for it.
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Convert read_sha1_file to take a pointer to struct object_id and rename
it read_object_file. Do the same for read_sha1_file_extended.
Convert one use in grep.c to use the new function without any other code
change, since the pointer being passed is a void pointer that is already
initialized with a pointer to struct object_id. Update the declaration
and definitions of the modified functions, and apply the following
semantic patch to convert the remaining callers:
@@
expression E1, E2, E3;
@@
- read_sha1_file(E1.hash, E2, E3)
+ read_object_file(&E1, E2, E3)
@@
expression E1, E2, E3;
@@
- read_sha1_file(E1->hash, E2, E3)
+ read_object_file(E1, E2, E3)
@@
expression E1, E2, E3, E4;
@@
- read_sha1_file_extended(E1.hash, E2, E3, E4)
+ read_object_file_extended(&E1, E2, E3, E4)
@@
expression E1, E2, E3, E4;
@@
- read_sha1_file_extended(E1->hash, E2, E3, E4)
+ read_object_file_extended(E1, E2, E3, E4)
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Convert get_tree_entry and find_tree_entry to take pointers to struct
object_id.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Convert the definition and declaration of write_sha1_file to
struct object_id and adjust usage of this function.
This commit also converts static function write_sha1_file_prepare, as it
is closely related.
Rename these functions to write_object_file and
write_object_file_prepare respectively.
Replace sha1_to_hex, hashcpy and hashclr with their oid equivalents
wherever possible.
Signed-off-by: Patryk Obara <patryk.obara@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Convert the definition of static recursive splice_tree function to use
struct object_id and adjust single caller.
Signed-off-by: Patryk Obara <patryk.obara@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This is one line shorter, and makes sure the length in the
malloc and sprintf steps match.
These conversions are very straightforward; we can drop the
malloc entirely, and replace the sprintf with xstrfmt.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Avoid scanning strings twice, once with strchr() and then with
strlen(), by using strchrnul().
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Rohit Mani <rohit.mani@outlook.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Deduplicate code by moving tree_desc initialization into a helper
function, fill_tree_desc_strict. It is like fill_tree_descriptor,
except that it only accepts tree hashes and no tree references (tags,
commits). No functional change.
Signed-off-by: René Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Convert the loop in score_trees() to tree_entry(). The code becomes
shorter and simpler because the calls to update_tree_entry() are not
needed any more.
Another benefit is that we need less variables to track the current
tree entries; as a side-effect of that the compiler has an easier
job figuring out the control flow and thus can avoid false warnings
about uninitialized variables.
Using struct name_entry also allows the use of tree_entry_len() for
finding the path length instead of strlen(), which may be slightly
more efficient.
Also unify the handling of missing entries in one of the two trees
(i.e. added or removed files): Just set cmp appropriately first, no
matter if we ran off the end of a tree or if we actually have two
entries to compare, and check its value a bit later without
duplicating the handler code.
Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This makes "subtree" more orthogonal to the rest of recursive merge, so
that you can use subtree and ours/theirs features at the same time. For
example, you can now say:
git merge -s subtree -Xtheirs other
to merge with "other" branch while shifting it up or down to match the
shape of the tree of the current branch, and resolving conflicts favoring
the changes "other" branch made over changes made in the current branch.
It also allows the prefix used to shift the trees to be specified using
the "-Xsubtree=$prefix" option. Giving an empty prefix tells the command
to figure out how much to shift trees automatically as we have always
done. "merge -s subtree" is the same as "merge -s recursive -Xsubtree="
(or "merge -s recursive -Xsubtree").
Based on an old patch done back in the days when git-merge was a script;
Avery ported the script part to builtin-merge.c. Bugs in shift_tree()
is mine.
Signed-off-by: Avery Pennarun <apenwarr@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This uses "git-apply --whitespace=strip" to fix whitespace errors that have
crept in to our source files over time. There are a few files that need
to have trailing whitespaces (most notably, test vectors). The results
still passes the test, and build result in Documentation/ area is unchanged.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This merge strategy largely piggy-backs on git-merge-recursive.
When merging trees A and B, if B corresponds to a subtree of A,
B is first adjusted to match the tree structure of A, instead of
reading the trees at the same level. This adjustment is also
done to the common ancestor tree.
If you are pulling updates from git-gui repository into git.git
repository, the root level of the former corresponds to git-gui/
subdirectory of the latter. The tree object of git-gui's toplevel
is wrapped in a fake tree object, whose sole entry has name 'git-gui'
and records object name of the true tree, before being used by
the 3-way merge code.
If you are merging the other way, only the git-gui/ subtree of
git.git is extracted and merged into git-gui's toplevel.
The detection of corresponding subtree is done by comparing the
pathnames and types in the toplevel of the tree.
Heuristics galore! That's the git way ;-).
Signed-off-by: Junio C Hamano <junkio@cox.net>
Junio C Hamano
Jeff King
Stefan Beller
brian m. carlson
Patryk Obara
Rohit Mani
René Scharfe
Shawn O. Pearce
Junio C Hamano