== Basic Summary ==
This series introduces a new mode to git merge-tree allowing it to perform
real merges (three-way text content merges, recursive ancestor
consolidation, rename detection, proper directory/file conflict handling,
etc.) and write the result as a toplevel tree. It doesn't touch the working
tree or index, and doesn't create any commits or update any refs. It could
be used to do merges when in a bare repository (thus potentially making it
of interest to Git hosting sites, i.e. "Server side merges"), or for doing a
merge of branches that aren't checked out.
It does not handle similar functionality for cherry-picks, rebases, or
reverts; that is also of interest, but is being deferred for a future
series.
== Quick Overview ==
* Patches 1-2: preparatory cleanups
* Patches 3-4: implement basic real merges
* Patches 5-6: include informational messages ("CONFLICT" messages and
such) in output
* Patches 7-10: add ability to include ls-files -u style of info in the
output
* Patch 11: support --allow-unrelated-histories
* Patch 12: augment the manual with potential usage mistakes
== Updates Log ==
Many thanks to the many reviewers who provided good feedback on the most
recent round -- Junio, Ævar, Josh, Emily, and perhaps some others I've
forgotten from review club.
Updates since v4:
* Fixed double "is" in documentation.
* Fixed a few small items with testcases
Updates since v3 (or v5, if you include the rounds at
https://lore.kernel.org/git/pull.1114.v2.git.git.1641403655.gitgitgadget@xxxxxxxxx/):
* Dropped previous patches 5, 6, and 8 of the old series; they weren't
being used and opened a can of worms[1]
* [Patch 3] Restructured argument checking, including using an enum
* [Patch 4] Restored the extended paragraph about the deprecated form of
git-merge-tree, mentioned write-tree in plumbing commands, and a few
other small fixups to the documentation
* [Patch 4] Also provide an example of a clean merge rather than just a
conflicted one
* [Patch 6] Fix the incompatible arguments check and add some tests for it
* [Patch 6] Introduce an anonymize_hash() shell function to make tests
easier to read (less repeated sed)
* [Patch 9] Rename --exclude-modes-oids-stages to --name-only; no short
option for now
* [Patch 10] When -z passed, the tree in the first section should have a
trailing NUL rather than trailing newline [1]
https://lore.kernel.org/git/CABPp-BEKuXHELVx4=5JJTj5HVOKZ=Y-4G4BK47BCZYYRSrkFsQ@xxxxxxxxxxxxxx/
Stuff NOT included that reviewers brought up in earlier rounds:
* Very generic (mode, oid, stage, filename) printing formatting[2]
* Always printing 3 stages for each filename with conflicts[3]
* Attempting to group conflict stages by logical conflict rather than by
affected target filepath[4]
* Providing similar functionality for doing cherry-picks/rebases/reverts,
i.e. a scheme for three-way merges with a specified merge-base[5]. That's
being deferred to a future series. [2]
https://lore.kernel.org/git/CABPp-BGnOes7J_piDyBUeuLVm274w4-9G3k0vR-0it3z7TPn_w@xxxxxxxxxxxxxx/
[3]
https://lore.kernel.org/git/CABPp-BG2rMEYBLuBW=0wtpJe4aUFGCFa8D0NTSKz9Sm+CkXPxw@xxxxxxxxxxxxxx/
[4]
https://lore.kernel.org/git/CABPp-BGCL0onSmpgKuO1k2spYCkx=v27ed9TSSxFib=OdDcLbw@xxxxxxxxxxxxxx/
[5]
https://lore.kernel.org/git/CABPp-BEaemkGGm0cSofP0gau7YN-y6HFoi0yJbHA8+iGjxsYSA@xxxxxxxxxxxxxx/
Updates since v2:
* Improved patches from Dscho for the diff_warn_rename_limit() handling
* Add a -z option for NUL-terminated conflict info lines (so that filenames
do not have to be quoted)
Updates since v1 (or v3 depending on how you count; thanks to René, Ævar,
Christian, Dscho for very helpful feedback):
* New patch from Dscho allowing diff_warn_rename_limit() to print somewhere
other than stdout (I hope he's okay with me including his Signed-off-by)
* Now prints filenames relative to prefix, much like ls-files
* Renamed --exclude-oids-and-modes to --exclude-modes-oids-stages and gave
it a -l shorthand; I'm wondering if I should just drop this option,
though.
* And numerous cleanups, in lots of areas:
* Multiple parse-options cleanups
* Lots of commit message cleanups
* Wording tweaks to the "Description" section of the manual
* Several small code cleanups
* I dropped the RFC label
Updates since original submission v2 (thanks to Christian, Dscho, Ramsay,
and René for suggestions and comments):
* Significant changes to output format:
* Flags no longer take a filename for additional output; they write to
stdout instead.
* More information included by default when there are conflicts (no need
to request it with additional flags, instead flags can be used to
suppress it).
* Provide (mode, oid, stage, file) tuples -- i.e. ls-files -u style of
information -- when there are conflicts. Add a flag to only list
conflicted files if that's preferred.
* Much more thorough manual for git-merge-tree.txt
* Renamed option from --real to --write-tree
* Accept an optional --trivial-merge option to get old style merge-tree
behavior
* Allow both --write-tree and --trivial-merge to be omitted since we can
deduce which from number of arguments
* Document exit code when the merge cannot be run (so we can distinguish
other error cases from conflicts)
* testcase cleanups: test_tick, early skip of test when using recursive
backend, variable renames, etc.
* various minor code cleanups
* Add a new --allow-unrelated-histories option (with same meaning as the
one used in git merge)
* Rebased on top of en/remerge-diff to avoid a small conflict
Updates since original submission v1 (thanks to Johannes Altmanninger and
Fabian for suggestions):
* Fixed a bad patch splitting, and a style issue pointed out by Johannes
Altimanninger
* Fixed misleading commit messages in new test cases
* Fixed my comments about how commit-tree could be used to correctly use
two -p flags
Elijah Newren (12):
merge-tree: rename merge_trees() to trivial_merge_trees()
merge-tree: move logic for existing merge into new function
merge-tree: add option parsing and initial shell for real merge
function
merge-tree: implement real merges
merge-ort: split out a separate display_update_messages() function
merge-tree: support including merge messages in output
merge-ort: provide a merge_get_conflicted_files() helper function
merge-tree: provide a list of which files have conflicts
merge-tree: provide easy access to `ls-files -u` style info
merge-tree: allow `ls-files -u` style info to be NUL terminated
merge-tree: add a --allow-unrelated-histories flag
git-merge-tree.txt: add a section on potentional usage mistakes
Documentation/git-merge-tree.txt | 204 ++++++++++++++++++++++++--
builtin/merge-tree.c | 189 ++++++++++++++++++++++--
git.c | 2 +-
merge-ort.c | 109 +++++++++-----
merge-ort.h | 29 ++++
t/t4301-merge-tree-write-tree.sh | 238 +++++++++++++++++++++++++++++++
6 files changed, 709 insertions(+), 62 deletions(-)
create mode 100755 t/t4301-merge-tree-write-tree.sh
base-commit: ea5df61cf358d3c831189e2f04863abc2157e3e1
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1122%2Fnewren%2Fin-core-merge-tree-v5
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1122/newren/in-core-merge-tree-v5
Pull-Request: https://github.com/gitgitgadget/git/pull/1122
Range-diff vs v4:
1: 4a7cd5542bb = 1: 4a7cd5542bb merge-tree: rename merge_trees() to trivial_merge_trees()
2: 4780ff6784d = 2: 4780ff6784d merge-tree: move logic for existing merge into new function
3: 60253745f5c = 3: 60253745f5c merge-tree: add option parsing and initial shell for real merge function
4: d7b51da94e6 ! 4: 7994775a934 merge-tree: implement real merges
@@ Documentation/git-merge-tree.txt: git-merge-tree(1)
+conflicting stages to the standard output in a semi-diff format.
+Since this was designed for higher level scripts to consume and merge
+the results back into the index, it omits entries that match
-+<branch1>. The result of this second form is is similar to what
++<branch1>. The result of this second form is similar to what
+three-way 'git read-tree -m' does, but instead of storing the results
+in the index, the command outputs the entries to the standard output.
+This form not only has limited applicability, the output format is
@@ t/t4301-merge-tree-write-tree.sh (new)
+. ./test-lib.sh
+
+# This test is ort-specific
-+if test "${GIT_TEST_MERGE_ALGORITHM}" != "ort"
++if test "$GIT_TEST_MERGE_ALGORITHM" != "ort"
+then
+ skip_all="GIT_TEST_MERGE_ALGORITHM != ort"
+ test_done
@@ t/t4301-merge-tree-write-tree.sh (new)
+'
+
+test_expect_success 'Clean merge' '
-+ git merge-tree --write-tree side1 side3 >RESULT &&
++ TREE_OID=$(git merge-tree --write-tree side1 side3) &&
+ q_to_tab <<-EOF >expect &&
+ 100644 blob $(git rev-parse side1:greeting)Qgreeting
+ 100644 blob $(git rev-parse side1:numbers)Qsequence
+ 100644 blob $(git rev-parse side1:whatever)Qwhatever
+ EOF
+
-+ git ls-tree $(cat RESULT) >actual &&
++ git ls-tree $TREE_OID >actual &&
+ test_cmp expect actual
+'
+
+test_expect_success 'Content merge and a few conflicts' '
+ git checkout side1^0 &&
+ test_must_fail git merge side2 &&
-+ expected_tree=$(cat .git/AUTO_MERGE) &&
++ expected_tree=$(git rev-parse AUTO_MERGE) &&
+
+ # We will redo the merge, while we are still in a conflicted state!
+ test_when_finished "git reset --hard" &&
@@ t/t4301-merge-tree-write-tree.sh (new)
+
+ # greeting should have a merge conflict
+ git show ${expected_tree}:greeting >tmp &&
-+ cat tmp | sed -e s/HEAD/side1/ >expect &&
++ sed -e s/HEAD/side1/ tmp >expect &&
+ git show ${actual_tree}:greeting >actual &&
+ test_cmp expect actual
+'
5: 58a5594aeb6 = 5: e0f95e094cf merge-ort: split out a separate display_update_messages() function
6: fa55cb4d644 = 6: 90c4adecb23 merge-tree: support including merge messages in output
7: f3ad7add515 = 7: 12e2351092a merge-ort: provide a merge_get_conflicted_files() helper function
8: 6058190d1b1 = 8: 5bb7d3725ad merge-tree: provide a list of which files have conflicts
9: 435f66ea699 ! 9: 3c2ca198cec merge-tree: provide easy access to `ls-files -u` style info
@@ builtin/merge-tree.c: int cmd_merge_tree(int argc, const char **argv, const char
## t/t4301-merge-tree-write-tree.sh ##
@@ t/t4301-merge-tree-write-tree.sh: test_expect_success 'Content merge and a few conflicts' '
- expected_tree=$(cat .git/AUTO_MERGE) &&
+ expected_tree=$(git rev-parse AUTO_MERGE) &&
# We will redo the merge, while we are still in a conflicted state!
+ git ls-files -u >conflicted-file-info &&
10: 5f253e298b3 = 10: 6e89e17693a merge-tree: allow `ls-files -u` style info to be NUL terminated
11: e706cf31c6e = 11: 6ddd5ffde9c merge-tree: add a --allow-unrelated-histories flag
12: c279236ab65 = 12: 7abf633b638 git-merge-tree.txt: add a section on potentional usage mistakes
--
gitgitgadget
