@matheusbsbs / matheus-bagliano / commits / 83f9dad7d6

contrib/subtree: fix split with squashed subtrees

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 <ask+git@howdoi.land> Acked-by: Phillip Wood <phillip.wood@dunelm.org.uk> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Colin Stagner committed Sep 9, 2025 at 22:11 UTC 83f9dad7d6fb5988b68f80b25bd87c68693195dd
2 files changed +99 -8
contrib/subtree/git-subtree.sh
+28 -8
index 3fddba797c..17106d1a72 100755 --- a/contrib/subtree/git-subtree.sh +++ b/contrib/subtree/git-subtree.sh @@ -785,20 +785,40 @@ ensure_valid_ref_format () { 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="$1" - if test -n "$(git log -1 --grep="git-subtree-dir:" $rev)" + + 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="${val%/}" ;; + git-subtree-mainline:) + have_mainline=y ;; + esac + done + + if test -n "${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: $arg_prefix$" $rev)" - then - return 0 - fi + return 0 fi return 1 + ) } # Usage: process_split_commit REV PARENTS
contrib/subtree/t/t7900-subtree.sh
+71
index 3edbb33af4..316dc5269e 100755 --- a/contrib/subtree/t/t7900-subtree.sh +++ b/contrib/subtree/t/t7900-subtree.sh @@ -9,6 +9,9 @@ This test verifies the basic operation of the add, merge, split, pull, and push subcommands of git subtree. ' +GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main +export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME + TEST_DIRECTORY=$(pwd)/../../../t . "$TEST_DIRECTORY"/test-lib.sh . "$TEST_DIRECTORY"/lib-gpg.sh @@ -68,6 +71,33 @@ 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 && @@ -426,6 +456,47 @@ 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 &&