git/t/t6412-merge-large-rename.sh
Patrick Steinhardt 52a7dab439 builtin/mv: refactor to use struct strvec
Memory allocation patterns in git-mv(1) are extremely hard to follow:
We copy around string pointers into manually-managed arrays, some of
which alias each other, but only sometimes, while we also drop some of
those strings at other times without ever daring to free them.

While this may be my own subjective feeling, it seems like others have
given up as the code has multiple calls to `UNLEAK()`. These are not
sufficient though, and git-mv(1) is still leaking all over the place
even with them.

Refactor the code to instead track strings in `struct strvec`. While
this has the effect of effectively duplicating some of the strings
without an actual need, it is way easier to reason about and fixes all
of the aliasing of memory that has been going on. It allows us to get
rid of the `UNLEAK()` calls and also fixes leaks that those calls did
not paper over.

Mark tests which are now leak-free accordingly.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-05-27 11:20:02 -07:00

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#!/bin/sh
test_description='merging with large rename matrix'
GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
TEST_PASSES_SANITIZE_LEAK=true
. ./test-lib.sh
count() {
i=1
while test $i -le $1; do
echo $i
i=$(($i + 1))
done
}
test_expect_success 'setup (initial)' '
touch file &&
git add . &&
git commit -m initial &&
git tag initial
'
make_text() {
echo $1: $2
for i in $(count 20); do
echo $1: $i
done
echo $1: $3
}
test_rename() {
test_expect_success "rename ($1, $2)" '
n='$1' &&
expect='$2' &&
git checkout -f main &&
test_might_fail git branch -D test$n &&
git reset --hard initial &&
for i in $(count $n); do
make_text $i initial initial >$i || return 1
done &&
git add . &&
git commit -m add=$n &&
for i in $(count $n); do
make_text $i changed initial >$i || return 1
done &&
git commit -a -m change=$n &&
git checkout -b test$n HEAD^ &&
for i in $(count $n); do
git rm $i &&
make_text $i initial changed >$i.moved || return 1
done &&
git add . &&
git commit -m change+rename=$n &&
case "$expect" in
ok) git merge main ;;
*) test_must_fail git merge main ;;
esac
'
}
test_rename 5 ok
test_expect_success 'set diff.renamelimit to 4' '
git config diff.renamelimit 4
'
test_rename 4 ok
test_rename 5 fail
test_expect_success 'set merge.renamelimit to 5' '
git config merge.renamelimit 5
'
test_rename 5 ok
test_rename 6 fail
test_expect_success 'setup large simple rename' '
git config --unset merge.renamelimit &&
git config --unset diff.renamelimit &&
git reset --hard initial &&
for i in $(count 200); do
make_text foo bar baz >$i || return 1
done &&
git add . &&
git commit -m create-files &&
git branch simple-change &&
git checkout -b simple-rename &&
mkdir builtin &&
git mv [0-9]* builtin/ &&
git commit -m renamed &&
git checkout simple-change &&
>unrelated-change &&
git add unrelated-change &&
git commit -m unrelated-change
'
test_expect_success 'massive simple rename does not spam added files' '
sane_unset GIT_MERGE_VERBOSITY &&
git merge --no-stat simple-rename | grep -v Removing >output &&
test_line_count -lt 5 output
'
test_done