builtin/mv: bail out when trying to move child and its parent
We have a known issue in git-mv(1) where moving both a child and any of its parents causes an assert to trigger because the child cannot be found anymore in the index. We have added a test for this in commit 0fcd473fdd3 (t7001: add failure test which triggers assertion, 2024-10-22) without addressing the issue, which is why the test itself is marked as `test_expect_failure`. The behaviour of that test relies on a call to assert(3p) though, which may or may not be compiled into the resulting binary depending on whether or not we pass `-DNDEBUG`. When these asserts are compiled into Git this may cause our CI to hang on Windows though, because asserts may cause a modal window to be shown. While we could work around the issue by converting this into a call to `BUG()`, let's rather address the root cause of the issue by bailing out in case we see that both a child and any of its parents are being moved in the same command. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Patrick Steinhardt committed
Apr 30, 2025 at 14:44 UTC
8583c9dcbc7d362250c0310e4cee771ec5003327
2 files changed
+79
-6
builtin/mv.c
+59
-2
@@ -37,6 +37,13 @@ enum update_mode {
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INDEX = (1 << 2),
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SPARSE = (1 << 3),
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SKIP_WORKTREE_DIR = (1 << 4),
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+ /*
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+ * A file gets moved implicitly via a move of one of its parent
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+ * directories. This flag causes us to skip the check that we don't try
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+ * to move a file and any of its parent directories at the same point
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+ * in time.
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+ */
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+ MOVE_VIA_PARENT_DIR = (1 << 5),
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};
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#define DUP_BASENAME 1
@@ -181,6 +188,21 @@ static void remove_empty_src_dirs(const char **src_dir, size_t src_dir_nr)
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strbuf_release(&a_src_dir);
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}
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+struct pathmap_entry {
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+ struct hashmap_entry ent;
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+ const char *path;
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+};
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+
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+static int pathmap_cmp(const void *cmp_data UNUSED,
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+ const struct hashmap_entry *a,
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+ const struct hashmap_entry *b,
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+ const void *key UNUSED)
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+{
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+ const struct pathmap_entry *e1 = container_of(a, struct pathmap_entry, ent);
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+ const struct pathmap_entry *e2 = container_of(b, struct pathmap_entry, ent);
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+ return fspathcmp(e1->path, e2->path);
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+}
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+
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int cmd_mv(int argc,
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const char **argv,
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const char *prefix,
@@ -211,6 +233,8 @@ int cmd_mv(int argc,
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struct cache_entry *ce;
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struct string_list only_match_skip_worktree = STRING_LIST_INIT_DUP;
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struct string_list dirty_paths = STRING_LIST_INIT_DUP;
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+ struct hashmap moved_dirs = HASHMAP_INIT(pathmap_cmp, NULL);
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+ struct strbuf pathbuf = STRBUF_INIT;
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int ret;
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git_config(git_default_config, NULL);
@@ -329,6 +353,7 @@ int cmd_mv(int argc,
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dir_check:
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if (S_ISDIR(st.st_mode)) {
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+ struct pathmap_entry *entry;
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char *dst_with_slash;
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size_t dst_with_slash_len;
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int j, n;
@@ -346,6 +371,11 @@ dir_check:
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goto act_on_entry;
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}
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+ entry = xmalloc(sizeof(*entry));
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+ entry->path = src;
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+ hashmap_entry_init(&entry->ent, fspathhash(src));
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+ hashmap_add(&moved_dirs, &entry->ent);
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+
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/* last - first >= 1 */
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modes[i] |= WORKING_DIRECTORY;
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@@ -366,8 +396,7 @@ dir_check:
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strvec_push(&sources, path);
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strvec_push(&destinations, prefixed_path);
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- memset(modes + argc + j, 0, sizeof(enum update_mode));
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- modes[argc + j] |= ce_skip_worktree(ce) ? SPARSE : INDEX;
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+ modes[argc + j] = MOVE_VIA_PARENT_DIR | (ce_skip_worktree(ce) ? SPARSE : INDEX);
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submodule_gitfiles[argc + j] = NULL;
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free(prefixed_path);
@@ -463,6 +492,32 @@ remove_entry:
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}
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}
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+ for (i = 0; i < argc; i++) {
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+ const char *slash_pos;
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+
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+ if (modes[i] & MOVE_VIA_PARENT_DIR)
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+ continue;
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+
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+ strbuf_reset(&pathbuf);
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+ strbuf_addstr(&pathbuf, sources.v[i]);
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+
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+ slash_pos = strrchr(pathbuf.buf, '/');
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+ while (slash_pos > pathbuf.buf) {
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+ struct pathmap_entry needle;
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+
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+ strbuf_setlen(&pathbuf, slash_pos - pathbuf.buf);
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+
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+ needle.path = pathbuf.buf;
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+ hashmap_entry_init(&needle.ent, fspathhash(pathbuf.buf));
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+
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+ if (hashmap_get_entry(&moved_dirs, &needle, ent, NULL))
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+ die(_("cannot move both '%s' and its parent directory '%s'"),
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+ sources.v[i], pathbuf.buf);
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+
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+ slash_pos = strrchr(pathbuf.buf, '/');
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+ }
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+ }
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+
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if (only_match_skip_worktree.nr) {
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advise_on_updating_sparse_paths(&only_match_skip_worktree);
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if (!ignore_errors) {
@@ -587,6 +642,8 @@ out:
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strvec_clear(&dest_paths);
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strvec_clear(&destinations);
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strvec_clear(&submodule_gitfiles_to_free);
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+ hashmap_clear_and_free(&moved_dirs, struct pathmap_entry, ent);
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+ strbuf_release(&pathbuf);
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free(submodule_gitfiles);
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free(modes);
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return ret;
t/t7001-mv.sh
+20
-4
@@ -550,16 +550,32 @@ test_expect_success 'moving nested submodules' '
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git status
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'
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-test_expect_failure 'nonsense mv triggers assertion failure and partially updated index' '
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+test_expect_success 'moving file and its parent directory at the same time fails' '
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test_when_finished git reset --hard HEAD &&
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git reset --hard HEAD &&
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mkdir -p a &&
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mkdir -p b &&
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>a/a.txt &&
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git add a/a.txt &&
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- test_must_fail git mv a/a.txt a b &&
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- git status --porcelain >actual &&
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- grep "^A[ ]*a/a.txt$" actual
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+ cat >expect <<-EOF &&
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+ fatal: cannot move both ${SQ}a/a.txt${SQ} and its parent directory ${SQ}a${SQ}
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+ EOF
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+ test_must_fail git mv a/a.txt a b 2>err &&
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+ test_cmp expect err
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+'
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+
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+test_expect_success 'moving nested directory and its parent directory at the same time fails' '
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+ test_when_finished git reset --hard HEAD &&
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+ git reset --hard HEAD &&
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+ mkdir -p a/b/c &&
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+ >a/b/c/file.txt &&
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+ git add a &&
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+ mkdir target &&
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+ cat >expect <<-EOF &&
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+ fatal: cannot move both ${SQ}a/b/c${SQ} and its parent directory ${SQ}a${SQ}
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+ EOF
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+ test_must_fail git mv a/b/c a target 2>err &&
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+ test_cmp expect err
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'
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test_done