rebase --update-refs: avoid unintended ref deletion

In b3b1a21d1a5 (sequencer: rewrite update-refs as user edits todo list, 2022-07-19), the 'todo_list_filter_update_refs()' step was added to handle the removal of 'update-ref' lines from a 'rebase-todo'. Specifically, it removes potential ref updates from the "update refs state" if a ref does not have a corresponding 'update-ref' line. However, because 'write_update_refs_state()' will not update the state if the 'refs_to_oids' list was empty, removing *all* 'update-ref' lines will result in the state remaining unchanged from how it was initialized (with all refs' "after" OID being null). Then, when the ref update is applied, all refs will be updated to null and consequently deleted. To fix this, delete the 'update-refs' state file when 'refs_to_oids' is empty. Additionally, add a tests covering "all update-ref lines removed" cases. Reported-by: herr.kaste <herr.kaste@gmail.com> Helped-by: Phillip Wood <phillip.wood@dunelm.org.uk> Helped-by: Derrick Stolee <derrickstolee@github.com> Signed-off-by: Victoria Dye <vdye@github.com> Signed-off-by: Taylor Blau <me@ttaylorr.com>

Victoria Dye committed Nov 7, 2022 at 09:47 UTC 93a7bc8b285eaad24049bc862b4733d595a473f8
2 files changed +113 -3
sequencer.c
+6 -3
@@ -4130,11 +4130,14 @@ static int write_update_refs_state(struct string_list *refs_to_oids)
4130 struct string_list_item *item;
4131 char *path;
4132
4133 - if (!refs_to_oids->nr)
4134 - return 0;
4135 -
4133 path = rebase_path_update_refs(the_repository->gitdir);
4134
4135 + if (!refs_to_oids->nr) {
4136 + if (unlink(path) && errno != ENOENT)
4137 + result = error_errno(_("could not unlink: %s"), path);
4138 + goto cleanup;
4139 + }
4140 +
4141 if (safe_create_leading_directories(path)) {
4142 result = error(_("unable to create leading directories of %s"),
4143 path);
t/t3404-rebase-interactive.sh
+107
@@ -1964,6 +1964,113 @@ test_expect_success 'respect user edits to update-ref steps' '
1964 test_cmp_rev HEAD refs/heads/no-conflict-branch
1965 '
1966
1967 +test_expect_success '--update-refs: all update-ref lines removed' '
1968 + git checkout -b test-refs-not-removed no-conflict-branch &&
1969 + git branch -f base HEAD~4 &&
1970 + git branch -f first HEAD~3 &&
1971 + git branch -f second HEAD~3 &&
1972 + git branch -f third HEAD~1 &&
1973 + git branch -f tip &&
1974 +
1975 + test_commit test-refs-not-removed &&
1976 + git commit --amend --fixup first &&
1977 +
1978 + git rev-parse first second third tip no-conflict-branch >expect-oids &&
1979 +
1980 + (
1981 + set_cat_todo_editor &&
1982 + test_must_fail git rebase -i --update-refs base >todo.raw &&
1983 + sed -e "/^update-ref/d" <todo.raw >todo
1984 + ) &&
1985 + (
1986 + set_replace_editor todo &&
1987 + git rebase -i --update-refs base
1988 + ) &&
1989 +
1990 + # Ensure refs are not deleted and their OIDs have not changed
1991 + git rev-parse first second third tip no-conflict-branch >actual-oids &&
1992 + test_cmp expect-oids actual-oids
1993 +'
1994 +
1995 +test_expect_success '--update-refs: all update-ref lines removed, then some re-added' '
1996 + git checkout -b test-refs-not-removed2 no-conflict-branch &&
1997 + git branch -f base HEAD~4 &&
1998 + git branch -f first HEAD~3 &&
1999 + git branch -f second HEAD~3 &&
2000 + git branch -f third HEAD~1 &&
2001 + git branch -f tip &&
2002 +
2003 + test_commit test-refs-not-removed2 &&
2004 + git commit --amend --fixup first &&
2005 +
2006 + git rev-parse first second third >expect-oids &&
2007 +
2008 + (
2009 + set_cat_todo_editor &&
2010 + test_must_fail git rebase -i \
2011 + --autosquash --update-refs \
2012 + base >todo.raw &&
2013 + sed -e "/^update-ref/d" <todo.raw >todo
2014 + ) &&
2015 +
2016 + # Add a break to the end of the todo so we can edit later
2017 + echo "break" >>todo &&
2018 +
2019 + (
2020 + set_replace_editor todo &&
2021 + git rebase -i --autosquash --update-refs base &&
2022 + echo "update-ref refs/heads/tip" >todo &&
2023 + git rebase --edit-todo &&
2024 + git rebase --continue
2025 + ) &&
2026 +
2027 + # Ensure first/second/third are unchanged, but tip is updated
2028 + git rev-parse first second third >actual-oids &&
2029 + test_cmp expect-oids actual-oids &&
2030 + test_cmp_rev HEAD tip
2031 +'
2032 +
2033 +test_expect_success '--update-refs: --edit-todo with no update-ref lines' '
2034 + git checkout -b test-refs-not-removed3 no-conflict-branch &&
2035 + git branch -f base HEAD~4 &&
2036 + git branch -f first HEAD~3 &&
2037 + git branch -f second HEAD~3 &&
2038 + git branch -f third HEAD~1 &&
2039 + git branch -f tip &&
2040 +
2041 + test_commit test-refs-not-removed3 &&
2042 + git commit --amend --fixup first &&
2043 +
2044 + git rev-parse first second third tip no-conflict-branch >expect-oids &&
2045 +
2046 + (
2047 + set_cat_todo_editor &&
2048 + test_must_fail git rebase -i \
2049 + --autosquash --update-refs \
2050 + base >todo.raw &&
2051 + sed -e "/^update-ref/d" <todo.raw >todo
2052 + ) &&
2053 +
2054 + # Add a break to the beginning of the todo so we can resume with no
2055 + # update-ref lines
2056 + echo "break" >todo.new &&
2057 + cat todo >>todo.new &&
2058 +
2059 + (
2060 + set_replace_editor todo.new &&
2061 + git rebase -i --autosquash --update-refs base &&
2062 +
2063 + # Make no changes when editing so update-refs is still empty
2064 + cat todo >todo.new &&
2065 + git rebase --edit-todo &&
2066 + git rebase --continue
2067 + ) &&
2068 +
2069 + # Ensure refs are not deleted and their OIDs have not changed
2070 + git rev-parse first second third tip no-conflict-branch >actual-oids &&
2071 + test_cmp expect-oids actual-oids
2072 +'
2073 +
2074 test_expect_success '--update-refs: check failed ref update' '
2075 git checkout -B update-refs-error no-conflict-branch &&
2076 git branch -f base HEAD~4 &&