git/t/t4058-diff-duplicates.sh
Patrick Steinhardt ecb5c4318c unpack-trees: detect mismatching number of cache-tree/index entries
Same as the preceding commit, we unconditionally dereference the index's
cache entries depending on the number of cache-tree entries, which can
lead to a segfault when the cache-tree is corrupted. Fix this bug.

This also makes t4058 pass with the leak sanitizer enabled.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-10-07 15:08:11 -07:00

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#!/bin/sh
# NOTICE:
# This testsuite does a number of diffs and checks that the output match.
# However, it is a "garbage in, garbage out" situation; the trees have
# duplicate entries for individual paths, and it results in diffs that do
# not make much sense. As such, it is not clear that the diffs are
# "correct". The primary purpose of these tests was to verify that
# diff-tree does not segfault, but there is perhaps some value in ensuring
# that the diff output isn't wildly unreasonable.
test_description='test tree diff when trees have duplicate entries'
TEST_PASSES_SANITIZE_LEAK=true
. ./test-lib.sh
# make_tree_entry <mode> <mode> <sha1>
#
# We have to rely on perl here because not all printfs understand
# hex escapes (only octal), and xxd is not portable.
make_tree_entry () {
printf '%s %s\0' "$1" "$2" &&
perl -e 'print chr(hex($_)) for ($ARGV[0] =~ /../g)' "$3"
}
# Like git-mktree, but without all of the pesky sanity checking.
# Arguments come in groups of three, each group specifying a single
# tree entry (see make_tree_entry above).
make_tree () {
while test $# -gt 2; do
make_tree_entry "$1" "$2" "$3"
shift; shift; shift
done |
git hash-object --literally -w -t tree --stdin
}
# this is kind of a convoluted setup, but matches
# a real-world case. Each tree contains four entries
# for the given path, one with one sha1, and three with
# the other. The first tree has them split across
# two subtrees (which are themselves duplicate entries in
# the root tree), and the second has them all in a single subtree.
test_expect_success 'create trees with duplicate entries' '
blob_one=$(echo one | git hash-object -w --stdin) &&
blob_two=$(echo two | git hash-object -w --stdin) &&
inner_one_a=$(make_tree \
100644 inner $blob_one
) &&
inner_one_b=$(make_tree \
100644 inner $blob_two \
100644 inner $blob_two \
100644 inner $blob_two
) &&
outer_one=$(make_tree \
040000 outer $inner_one_a \
040000 outer $inner_one_b
) &&
inner_two=$(make_tree \
100644 inner $blob_one \
100644 inner $blob_two \
100644 inner $blob_two \
100644 inner $blob_two
) &&
outer_two=$(make_tree \
040000 outer $inner_two
) &&
git tag one $outer_one &&
git tag two $outer_two
'
test_expect_success 'create tree without duplicate entries' '
blob_one=$(echo one | git hash-object -w --stdin) &&
outer_three=$(make_tree \
100644 renamed $blob_one
) &&
git tag three $outer_three
'
test_expect_success 'diff-tree between duplicate trees' '
# See NOTICE at top of file
{
printf ":000000 100644 $ZERO_OID $blob_two A\touter/inner\n" &&
printf ":000000 100644 $ZERO_OID $blob_two A\touter/inner\n" &&
printf ":000000 100644 $ZERO_OID $blob_two A\touter/inner\n" &&
printf ":100644 000000 $blob_two $ZERO_OID D\touter/inner\n" &&
printf ":100644 000000 $blob_two $ZERO_OID D\touter/inner\n" &&
printf ":100644 000000 $blob_two $ZERO_OID D\touter/inner\n"
} >expect &&
git diff-tree -r --no-abbrev one two >actual &&
test_cmp expect actual
'
test_expect_success 'diff-tree with renames' '
# See NOTICE at top of file.
git diff-tree -M -r --no-abbrev one two >actual &&
test_must_be_empty actual
'
test_expect_success 'diff-tree FROM duplicate tree' '
# See NOTICE at top of file.
{
printf ":100644 000000 $blob_one $ZERO_OID D\touter/inner\n" &&
printf ":100644 000000 $blob_two $ZERO_OID D\touter/inner\n" &&
printf ":100644 000000 $blob_two $ZERO_OID D\touter/inner\n" &&
printf ":100644 000000 $blob_two $ZERO_OID D\touter/inner\n" &&
printf ":000000 100644 $ZERO_OID $blob_one A\trenamed\n"
} >expect &&
git diff-tree -r --no-abbrev one three >actual &&
test_cmp expect actual
'
test_expect_success 'diff-tree FROM duplicate tree, with renames' '
# See NOTICE at top of file.
{
printf ":100644 000000 $blob_two $ZERO_OID D\touter/inner\n" &&
printf ":100644 000000 $blob_two $ZERO_OID D\touter/inner\n" &&
printf ":100644 000000 $blob_two $ZERO_OID D\touter/inner\n" &&
printf ":100644 100644 $blob_one $blob_one R100\touter/inner\trenamed\n"
} >expect &&
git diff-tree -M -r --no-abbrev one three >actual &&
test_cmp expect actual
'
test_expect_success 'create a few commits' '
git commit-tree -m "Duplicate Entries" two^{tree} >commit_id &&
git branch base $(cat commit_id) &&
git commit-tree -p $(cat commit_id) -m "Just one" three^{tree} >up &&
git branch update $(cat up) &&
git commit-tree -p $(cat up) -m "Back to weird" two^{tree} >final &&
git branch final $(cat final) &&
rm commit_id up final
'
test_expect_success 'git read-tree does not segfault' '
test_must_fail git read-tree --reset base 2>err &&
test_grep "error: corrupted cache-tree has entries not present in index" err
'
test_expect_success 'reset --hard does not segfault' '
git checkout base &&
test_must_fail git reset --hard 2>err &&
test_grep "error: corrupted cache-tree has entries not present in index" err
'
test_expect_success 'git diff HEAD does not segfault' '
git checkout base &&
GIT_TEST_CHECK_CACHE_TREE=false &&
git reset --hard &&
test_must_fail git diff HEAD 2>err &&
test_grep "error: corrupted cache-tree has entries not present in index" err
'
test_expect_failure 'can switch to another branch when status is empty' '
git clean -ffdqx &&
git status --porcelain -uno >actual &&
test_must_be_empty actual &&
git checkout update
'
test_expect_success 'forcibly switch to another branch, verify status empty' '
git checkout -f update &&
git status --porcelain -uno >actual &&
test_must_be_empty actual
'
test_expect_success 'fast-forward from non-duplicate entries to duplicate' '
git merge final
'
test_expect_failure 'clean status, switch branches, status still clean' '
git status --porcelain -uno >actual &&
test_must_be_empty actual &&
git checkout base &&
git status --porcelain -uno >actual &&
test_must_be_empty actual
'
test_expect_success 'switch to base branch and force status to be clean' '
git checkout base &&
GIT_TEST_CHECK_CACHE_TREE=false git reset --hard &&
git status --porcelain -uno >actual &&
test_must_be_empty actual
'
test_expect_failure 'fast-forward from duplicate entries to non-duplicate' '
git merge update
'
test_done