From: Phillip Wood Date: Wed, 10 Sep 2025 09:39:00 GMT Subject: Re: [PATCH v3] contrib/subtree: fix split with squashed subtrees Message-ID: In-Reply-To: <20250910031124.1807856-1-ask+git@howdoi.land> Hi Colin Thanks for working on this. I'm not particularly familiar with git-subtree but as far as I can see this version looks good. Thanks Phillip On 10/09/2025 04:11, Colin Stagner wrote: > 98ba49ccc2 (subtree: fix split processing with multiple subtrees > present, 2023-12-01) increases the performance of > > git subtree split --prefix=subA > > by ignoring subtree merges which are outside of `subA/`. It also > introduces a regression. Subtree merges that should be retained > are incorrectly ignored if they: > > 1. are nested under `subA/`; and > 2. are merged with `--squash`. > > For example, a subtree merged like: > > git subtree merge --squash --prefix=subA/subB "$rev" > # ^^^^^^^^ ^^^^ > > is erroneously ignored during a split of `subA`. This causes > missing tree files and different commit hashes starting in > git v2.44.0-rc0. > > The method: > > should_ignore_subtree_split_commit REV > > should test only a single commit REV, but the combination of > > git log -1 --grep=... > > actually searches all *parent* commits until a `--grep` match is > discovered. > > Rewrite this method to test only one REV at a time. Extract commit > information with a single `git` call as opposed to three. The > `test` conditions for rejecting a commit remain unchanged. > > Unit tests now cover nested subtrees. > > Signed-off-by: Colin Stagner > --- > > Notes: > This bugfix patch is intended for maint-2.44 and up. > > contrib/subtree/git-subtree.sh | 36 +++++++++++---- > contrib/subtree/t/t7900-subtree.sh | 71 ++++++++++++++++++++++++++++++ > 2 files changed, 99 insertions(+), 8 deletions(-) > > diff --git a/contrib/subtree/git-subtree.sh b/contrib/subtree/git-subtree.sh > index 5dab3f506c..ad9b9b0191 100755 > --- a/contrib/subtree/git-subtree.sh > +++ b/contrib/subtree/git-subtree.sh > @@ -783,24 +783,44 @@ ensure_clean () { > # Usage: ensure_valid_ref_format REF > ensure_valid_ref_format () { > assert test $# = 1 > git check-ref-format "refs/heads/$1" || > die "fatal: '$1' does not look like a ref" > } > > -# Usage: check if a commit from another subtree should be > +# Usage: should_ignore_subtree_split_commit REV > +# > +# Check if REV is a commit from another subtree and should be > # ignored from processing for splits > should_ignore_subtree_split_commit () { > assert test $# = 1 > - local rev="$1" > + > + git show \ > + --no-patch \ > + --no-show-signature \ > + --format='%(trailers:key=git-subtree-dir,key=git-subtree-mainline)' \ > + "$1" | > + ( > + have_mainline= > + subtree_dir= > + > + while read -r trailer val > + do > + case "$trailer" in > + git-subtree-dir:) > + subtree_dir="${val%/}" ;; > + git-subtree-mainline:) > + have_mainline=y ;; > + esac > + done > + > - if test -n "$(git log -1 --grep="git-subtree-dir:" $rev)" > + if test -n "${subtree_dir}" && > + test -z "${have_mainline}" && > + test "${subtree_dir}" != "$arg_prefix" > then > - if test -z "$(git log -1 --grep="git-subtree-mainline:" $rev)" && > - test -z "$(git log -1 --grep="git-subtree-dir: $arg_prefix$" $rev)" > - then > - return 0 > - fi > + return 0 > fi > return 1 > + ) > } > > # Usage: process_split_commit REV PARENTS > diff --git a/contrib/subtree/t/t7900-subtree.sh b/contrib/subtree/t/t7900-subtree.sh > index ca4df5be83..25be40e12b 100755 > --- a/contrib/subtree/t/t7900-subtree.sh > +++ b/contrib/subtree/t/t7900-subtree.sh > @@ -9,6 +9,9 @@ This test verifies the basic operation of the add, merge, split, pull, > and push subcommands of git subtree. > ' > > +GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main > +export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME > + > TEST_DIRECTORY=$(pwd)/../../../t > . "$TEST_DIRECTORY"/test-lib.sh > > @@ -67,6 +70,33 @@ test_create_pre2_32_repo () { > git -C "$1-clone" replace HEAD^2 $new_commit > } > > +# test_create_subtree_add REPO ORPHAN PREFIX FILENAME ... > +# > +# Create a simple subtree on a new branch named ORPHAN in REPO. > +# The subtree is then merged into the current branch of REPO, > +# under PREFIX. The generated subtree has has one commit > +# with subject and tag FILENAME with a single file "FILENAME.t" > +# > +# When this method returns: > +# - the current branch of REPO will have file PREFIX/FILENAME.t > +# - REPO will have a branch named ORPHAN with subtree history > +# > +# additional arguments are forwarded to "subtree add" > +test_create_subtree_add () { > + ( > + cd "$1" && > + orphan="$2" && > + prefix="$3" && > + filename="$4" && > + shift 4 && > + last="$(git branch --show-current)" && > + git switch --orphan "$orphan" && > + test_commit "$filename" && > + git checkout "$last" && > + git subtree add --prefix="$prefix" "$@" "$orphan" > + ) > +} > + > test_expect_success 'shows short help text for -h' ' > test_expect_code 129 git subtree -h >out 2>err && > test_must_be_empty err && > @@ -425,6 +455,47 @@ test_expect_success 'split with multiple subtrees' ' > --squash --rejoin -d -m "Sub B Split 1" 2>&1 | grep -w "\[1\]")" = "" > ' > > +# When subtree split-ing a directory that has other subtree > +# *merges* underneath it, the split must include those subtrees. > +# This test creates a nested subtree, `subA/subB`, and tests > +# that the tree is correct after a subtree split of `subA/`. > +# The test covers: > +# - An initial `subtree add`; and > +# - A follow-up `subtree merge` > +# both with and without `--squashed`. > +for is_squashed in '' 'y' > +do > + test_expect_success "split keeps nested ${is_squashed:+--squash }subtrees that are part of the split" ' > + subtree_test_create_repo "$test_count" && > + ( > + cd "$test_count" && > + mkdir subA && > + test_commit subA/file1 && > + test_create_subtree_add \ > + . mksubtree subA/subB file2 ${is_squashed:+--squash} && > + test_path_is_file subA/file1.t && > + test_path_is_file subA/subB/file2.t && > + git subtree split --prefix=subA --branch=bsplit && > + git checkout bsplit && > + test_path_is_file file1.t && > + test_path_is_file subB/file2.t && > + git checkout mksubtree && > + git branch -D bsplit && > + test_commit file3 && > + git checkout main && > + git subtree merge \ > + ${is_squashed:+--squash} \ > + --prefix=subA/subB mksubtree && > + test_path_is_file subA/subB/file3.t && > + git subtree split --prefix=subA --branch=bsplit && > + git checkout bsplit && > + test_path_is_file file1.t && > + test_path_is_file subB/file2.t && > + test_path_is_file subB/file3.t > + ) > + ' > +done > + > test_expect_success 'split sub dir/ with --rejoin from scratch' ' > subtree_test_create_repo "$test_count" && > test_create_commit "$test_count" main1 && > > base-commit: 09669c729af92144fde84e97d358759b5b42b555