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authorJunio C Hamano <gitster@pobox.com>2015-05-22 19:41:53 (GMT)
committerJunio C Hamano <gitster@pobox.com>2015-05-22 19:41:53 (GMT)
commitfaa4b2ecbb6ea5fdc8d685343c4985dfb97f4dbf (patch)
treed1b84e4486c3ecb087b12193219bc35798d532a8
parent91c90876defc60b444d8dcfcff057eafc37991b5 (diff)
parentc628edfddbf37eefab810a3107a2c32b45abaedc (diff)
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Merge branch 'mh/ref-directory-file'
The ref API did not handle cases where 'refs/heads/xyzzy/frotz' is removed at the same time as 'refs/heads/xyzzy' is added (or vice versa) very well. * mh/ref-directory-file: reflog_expire(): integrate lock_ref_sha1_basic() errors into ours ref_transaction_commit(): delete extra "the" from error message ref_transaction_commit(): provide better error messages rename_ref(): integrate lock_ref_sha1_basic() errors into ours lock_ref_sha1_basic(): improve diagnostics for ref D/F conflicts lock_ref_sha1_basic(): report errors via a "struct strbuf *err" verify_refname_available(): report errors via a "struct strbuf *err" verify_refname_available(): rename function refs: check for D/F conflicts among refs created in a transaction ref_transaction_commit(): use a string_list for detecting duplicates is_refname_available(): use dirname in first loop struct nonmatching_ref_data: store a refname instead of a ref_entry report_refname_conflict(): inline function entry_matches(): inline function is_refname_available(): convert local variable "dirname" to strbuf is_refname_available(): avoid shadowing "dir" variable is_refname_available(): revamp the comments t1404: new tests of ref D/F conflicts within transactions
-rw-r--r--refs.c309
-rwxr-xr-xt/t1400-update-ref.sh14
-rwxr-xr-xt/t1404-update-ref-df-conflicts.sh107
3 files changed, 312 insertions, 118 deletions
diff --git a/refs.c b/refs.c
index 825a1f6..f704ee2 100644
--- a/refs.c
+++ b/refs.c
@@ -268,7 +268,7 @@ struct ref_dir {
* presence of an empty subdirectory does not block the creation of a
* similarly-named reference. (The fact that reference names with the
* same leading components can conflict *with each other* is a
- * separate issue that is regulated by is_refname_available().)
+ * separate issue that is regulated by verify_refname_available().)
*
* Please note that the name field contains the fully-qualified
* reference (or subdirectory) name. Space could be saved by only
@@ -844,121 +844,181 @@ static void prime_ref_dir(struct ref_dir *dir)
}
}
-static int entry_matches(struct ref_entry *entry, const struct string_list *list)
-{
- return list && string_list_has_string(list, entry->name);
-}
-
struct nonmatching_ref_data {
const struct string_list *skip;
- struct ref_entry *found;
+ const char *conflicting_refname;
};
static int nonmatching_ref_fn(struct ref_entry *entry, void *vdata)
{
struct nonmatching_ref_data *data = vdata;
- if (entry_matches(entry, data->skip))
+ if (data->skip && string_list_has_string(data->skip, entry->name))
return 0;
- data->found = entry;
+ data->conflicting_refname = entry->name;
return 1;
}
-static void report_refname_conflict(struct ref_entry *entry,
- const char *refname)
-{
- error("'%s' exists; cannot create '%s'", entry->name, refname);
-}
-
/*
- * Return true iff a reference named refname could be created without
- * conflicting with the name of an existing reference in dir. If
- * skip is non-NULL, ignore potential conflicts with refs in skip
- * (e.g., because they are scheduled for deletion in the same
- * operation).
+ * Return 0 if a reference named refname could be created without
+ * conflicting with the name of an existing reference in dir.
+ * Otherwise, return a negative value and write an explanation to err.
+ * If extras is non-NULL, it is a list of additional refnames with
+ * which refname is not allowed to conflict. If skip is non-NULL,
+ * ignore potential conflicts with refs in skip (e.g., because they
+ * are scheduled for deletion in the same operation). Behavior is
+ * undefined if the same name is listed in both extras and skip.
*
* Two reference names conflict if one of them exactly matches the
- * leading components of the other; e.g., "foo/bar" conflicts with
- * both "foo" and with "foo/bar/baz" but not with "foo/bar" or
- * "foo/barbados".
+ * leading components of the other; e.g., "refs/foo/bar" conflicts
+ * with both "refs/foo" and with "refs/foo/bar/baz" but not with
+ * "refs/foo/bar" or "refs/foo/barbados".
*
- * skip must be sorted.
+ * extras and skip must be sorted.
*/
-static int is_refname_available(const char *refname,
- const struct string_list *skip,
- struct ref_dir *dir)
+static int verify_refname_available(const char *refname,
+ const struct string_list *extras,
+ const struct string_list *skip,
+ struct ref_dir *dir,
+ struct strbuf *err)
{
const char *slash;
- size_t len;
int pos;
- char *dirname;
+ struct strbuf dirname = STRBUF_INIT;
+ int ret = -1;
+
+ /*
+ * For the sake of comments in this function, suppose that
+ * refname is "refs/foo/bar".
+ */
+ assert(err);
+
+ strbuf_grow(&dirname, strlen(refname) + 1);
for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
+ /* Expand dirname to the new prefix, not including the trailing slash: */
+ strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len);
+
/*
- * We are still at a leading dir of the refname; we are
- * looking for a conflict with a leaf entry.
- *
- * If we find one, we still must make sure it is
- * not in "skip".
+ * We are still at a leading dir of the refname (e.g.,
+ * "refs/foo"; if there is a reference with that name,
+ * it is a conflict, *unless* it is in skip.
*/
- pos = search_ref_dir(dir, refname, slash - refname);
- if (pos >= 0) {
- struct ref_entry *entry = dir->entries[pos];
- if (entry_matches(entry, skip))
- return 1;
- report_refname_conflict(entry, refname);
- return 0;
+ if (dir) {
+ pos = search_ref_dir(dir, dirname.buf, dirname.len);
+ if (pos >= 0 &&
+ (!skip || !string_list_has_string(skip, dirname.buf))) {
+ /*
+ * We found a reference whose name is
+ * a proper prefix of refname; e.g.,
+ * "refs/foo", and is not in skip.
+ */
+ strbuf_addf(err, "'%s' exists; cannot create '%s'",
+ dirname.buf, refname);
+ goto cleanup;
+ }
}
+ if (extras && string_list_has_string(extras, dirname.buf) &&
+ (!skip || !string_list_has_string(skip, dirname.buf))) {
+ strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
+ refname, dirname.buf);
+ goto cleanup;
+ }
/*
* Otherwise, we can try to continue our search with
- * the next component; if we come up empty, we know
- * there is nothing under this whole prefix.
+ * the next component. So try to look up the
+ * directory, e.g., "refs/foo/". If we come up empty,
+ * we know there is nothing under this whole prefix,
+ * but even in that case we still have to continue the
+ * search for conflicts with extras.
*/
- pos = search_ref_dir(dir, refname, slash + 1 - refname);
- if (pos < 0)
- return 1;
-
- dir = get_ref_dir(dir->entries[pos]);
+ strbuf_addch(&dirname, '/');
+ if (dir) {
+ pos = search_ref_dir(dir, dirname.buf, dirname.len);
+ if (pos < 0) {
+ /*
+ * There was no directory "refs/foo/",
+ * so there is nothing under this
+ * whole prefix. So there is no need
+ * to continue looking for conflicting
+ * references. But we need to continue
+ * looking for conflicting extras.
+ */
+ dir = NULL;
+ } else {
+ dir = get_ref_dir(dir->entries[pos]);
+ }
+ }
}
/*
- * We are at the leaf of our refname; we want to
- * make sure there are no directories which match it.
+ * We are at the leaf of our refname (e.g., "refs/foo/bar").
+ * There is no point in searching for a reference with that
+ * name, because a refname isn't considered to conflict with
+ * itself. But we still need to check for references whose
+ * names are in the "refs/foo/bar/" namespace, because they
+ * *do* conflict.
*/
- len = strlen(refname);
- dirname = xmallocz(len + 1);
- sprintf(dirname, "%s/", refname);
- pos = search_ref_dir(dir, dirname, len + 1);
- free(dirname);
+ strbuf_addstr(&dirname, refname + dirname.len);
+ strbuf_addch(&dirname, '/');
+
+ if (dir) {
+ pos = search_ref_dir(dir, dirname.buf, dirname.len);
+
+ if (pos >= 0) {
+ /*
+ * We found a directory named "$refname/"
+ * (e.g., "refs/foo/bar/"). It is a problem
+ * iff it contains any ref that is not in
+ * "skip".
+ */
+ struct nonmatching_ref_data data;
+
+ data.skip = skip;
+ data.conflicting_refname = NULL;
+ dir = get_ref_dir(dir->entries[pos]);
+ sort_ref_dir(dir);
+ if (do_for_each_entry_in_dir(dir, 0, nonmatching_ref_fn, &data)) {
+ strbuf_addf(err, "'%s' exists; cannot create '%s'",
+ data.conflicting_refname, refname);
+ goto cleanup;
+ }
+ }
+ }
- if (pos >= 0) {
+ if (extras) {
/*
- * We found a directory named "refname". It is a
- * problem iff it contains any ref that is not
- * in "skip".
+ * Check for entries in extras that start with
+ * "$refname/". We do that by looking for the place
+ * where "$refname/" would be inserted in extras. If
+ * there is an entry at that position that starts with
+ * "$refname/" and is not in skip, then we have a
+ * conflict.
*/
- struct ref_entry *entry = dir->entries[pos];
- struct ref_dir *dir = get_ref_dir(entry);
- struct nonmatching_ref_data data;
+ for (pos = string_list_find_insert_index(extras, dirname.buf, 0);
+ pos < extras->nr; pos++) {
+ const char *extra_refname = extras->items[pos].string;
- data.skip = skip;
- sort_ref_dir(dir);
- if (!do_for_each_entry_in_dir(dir, 0, nonmatching_ref_fn, &data))
- return 1;
+ if (!starts_with(extra_refname, dirname.buf))
+ break;
- report_refname_conflict(data.found, refname);
- return 0;
+ if (!skip || !string_list_has_string(skip, extra_refname)) {
+ strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
+ refname, extra_refname);
+ goto cleanup;
+ }
+ }
}
- /*
- * There is no point in searching for another leaf
- * node which matches it; such an entry would be the
- * ref we are looking for, not a conflict.
- */
- return 1;
+ /* No conflicts were found */
+ ret = 0;
+
+cleanup:
+ strbuf_release(&dirname);
+ return ret;
}
struct packed_ref_cache {
@@ -2294,8 +2354,10 @@ int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
*/
static struct ref_lock *lock_ref_sha1_basic(const char *refname,
const unsigned char *old_sha1,
+ const struct string_list *extras,
const struct string_list *skip,
- unsigned int flags, int *type_p)
+ unsigned int flags, int *type_p,
+ struct strbuf *err)
{
const char *ref_file;
const char *orig_refname = refname;
@@ -2306,6 +2368,8 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
int resolve_flags = 0;
int attempts_remaining = 3;
+ assert(err);
+
lock = xcalloc(1, sizeof(struct ref_lock));
if (mustexist)
@@ -2327,7 +2391,12 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
ref_file = git_path("%s", orig_refname);
if (remove_empty_directories(ref_file)) {
last_errno = errno;
- error("there are still refs under '%s'", orig_refname);
+
+ if (!verify_refname_available(orig_refname, extras, skip,
+ get_loose_refs(&ref_cache), err))
+ strbuf_addf(err, "there are still refs under '%s'",
+ orig_refname);
+
goto error_return;
}
refname = resolve_ref_unsafe(orig_refname, resolve_flags,
@@ -2337,8 +2406,12 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
*type_p = type;
if (!refname) {
last_errno = errno;
- error("unable to resolve reference %s: %s",
- orig_refname, strerror(errno));
+ if (last_errno != ENOTDIR ||
+ !verify_refname_available(orig_refname, extras, skip,
+ get_loose_refs(&ref_cache), err))
+ strbuf_addf(err, "unable to resolve reference %s: %s",
+ orig_refname, strerror(last_errno));
+
goto error_return;
}
/*
@@ -2348,7 +2421,8 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
* our refname.
*/
if (is_null_sha1(lock->old_sha1) &&
- !is_refname_available(refname, skip, get_packed_refs(&ref_cache))) {
+ verify_refname_available(refname, extras, skip,
+ get_packed_refs(&ref_cache), err)) {
last_errno = ENOTDIR;
goto error_return;
}
@@ -2374,7 +2448,7 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
/* fall through */
default:
last_errno = errno;
- error("unable to create directory for %s", ref_file);
+ strbuf_addf(err, "unable to create directory for %s", ref_file);
goto error_return;
}
@@ -2388,10 +2462,7 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
*/
goto retry;
else {
- struct strbuf err = STRBUF_INIT;
- unable_to_lock_message(ref_file, errno, &err);
- error("%s", err.buf);
- strbuf_release(&err);
+ unable_to_lock_message(ref_file, errno, err);
goto error_return;
}
}
@@ -2785,12 +2856,19 @@ static int rename_tmp_log(const char *newrefname)
static int rename_ref_available(const char *oldname, const char *newname)
{
struct string_list skip = STRING_LIST_INIT_NODUP;
+ struct strbuf err = STRBUF_INIT;
int ret;
string_list_insert(&skip, oldname);
- ret = is_refname_available(newname, &skip, get_packed_refs(&ref_cache))
- && is_refname_available(newname, &skip, get_loose_refs(&ref_cache));
+ ret = !verify_refname_available(newname, NULL, &skip,
+ get_packed_refs(&ref_cache), &err)
+ && !verify_refname_available(newname, NULL, &skip,
+ get_loose_refs(&ref_cache), &err);
+ if (!ret)
+ error("%s", err.buf);
+
string_list_clear(&skip, 0);
+ strbuf_release(&err);
return ret;
}
@@ -2806,6 +2884,7 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms
struct stat loginfo;
int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
const char *symref = NULL;
+ struct strbuf err = STRBUF_INIT;
if (log && S_ISLNK(loginfo.st_mode))
return error("reflog for %s is a symlink", oldrefname);
@@ -2848,9 +2927,10 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms
logmoved = log;
- lock = lock_ref_sha1_basic(newrefname, NULL, NULL, 0, NULL);
+ lock = lock_ref_sha1_basic(newrefname, NULL, NULL, NULL, 0, NULL, &err);
if (!lock) {
- error("unable to lock %s for update", newrefname);
+ error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);
+ strbuf_release(&err);
goto rollback;
}
hashcpy(lock->old_sha1, orig_sha1);
@@ -2864,9 +2944,10 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms
return 0;
rollback:
- lock = lock_ref_sha1_basic(oldrefname, NULL, NULL, 0, NULL);
+ lock = lock_ref_sha1_basic(oldrefname, NULL, NULL, NULL, 0, NULL, &err);
if (!lock) {
- error("unable to lock %s for rollback", oldrefname);
+ error("unable to lock %s for rollback: %s", oldrefname, err.buf);
+ strbuf_release(&err);
goto rollbacklog;
}
@@ -3746,25 +3827,18 @@ int update_ref(const char *msg, const char *refname,
return 0;
}
-static int ref_update_compare(const void *r1, const void *r2)
-{
- const struct ref_update * const *u1 = r1;
- const struct ref_update * const *u2 = r2;
- return strcmp((*u1)->refname, (*u2)->refname);
-}
-
-static int ref_update_reject_duplicates(struct ref_update **updates, int n,
+static int ref_update_reject_duplicates(struct string_list *refnames,
struct strbuf *err)
{
- int i;
+ int i, n = refnames->nr;
assert(err);
for (i = 1; i < n; i++)
- if (!strcmp(updates[i - 1]->refname, updates[i]->refname)) {
+ if (!strcmp(refnames->items[i - 1].string, refnames->items[i].string)) {
strbuf_addf(err,
"Multiple updates for ref '%s' not allowed.",
- updates[i]->refname);
+ refnames->items[i].string);
return 1;
}
return 0;
@@ -3778,6 +3852,7 @@ int ref_transaction_commit(struct ref_transaction *transaction,
struct ref_update **updates = transaction->updates;
struct string_list refs_to_delete = STRING_LIST_INIT_NODUP;
struct string_list_item *ref_to_delete;
+ struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
assert(err);
@@ -3789,9 +3864,11 @@ int ref_transaction_commit(struct ref_transaction *transaction,
return 0;
}
- /* Copy, sort, and reject duplicate refs */
- qsort(updates, n, sizeof(*updates), ref_update_compare);
- if (ref_update_reject_duplicates(updates, n, err)) {
+ /* Fail if a refname appears more than once in the transaction: */
+ for (i = 0; i < n; i++)
+ string_list_append(&affected_refnames, updates[i]->refname);
+ string_list_sort(&affected_refnames);
+ if (ref_update_reject_duplicates(&affected_refnames, err)) {
ret = TRANSACTION_GENERIC_ERROR;
goto cleanup;
}
@@ -3812,15 +3889,20 @@ int ref_transaction_commit(struct ref_transaction *transaction,
update->refname,
((update->flags & REF_HAVE_OLD) ?
update->old_sha1 : NULL),
- NULL,
+ &affected_refnames, NULL,
update->flags,
- &update->type);
+ &update->type,
+ err);
if (!update->lock) {
+ char *reason;
+
ret = (errno == ENOTDIR)
? TRANSACTION_NAME_CONFLICT
: TRANSACTION_GENERIC_ERROR;
- strbuf_addf(err, "Cannot lock the ref '%s'.",
- update->refname);
+ reason = strbuf_detach(err, NULL);
+ strbuf_addf(err, "Cannot lock ref '%s': %s",
+ update->refname, reason);
+ free(reason);
goto cleanup;
}
if ((update->flags & REF_HAVE_NEW) &&
@@ -3913,6 +3995,7 @@ cleanup:
if (updates[i]->lock)
unlock_ref(updates[i]->lock);
string_list_clear(&refs_to_delete, 0);
+ string_list_clear(&affected_refnames, 0);
return ret;
}
@@ -4102,6 +4185,7 @@ int reflog_expire(const char *refname, const unsigned char *sha1,
char *log_file;
int status = 0;
int type;
+ struct strbuf err = STRBUF_INIT;
memset(&cb, 0, sizeof(cb));
cb.flags = flags;
@@ -4113,9 +4197,12 @@ int reflog_expire(const char *refname, const unsigned char *sha1,
* reference itself, plus we might need to update the
* reference if --updateref was specified:
*/
- lock = lock_ref_sha1_basic(refname, sha1, NULL, 0, &type);
- if (!lock)
- return error("cannot lock ref '%s'", refname);
+ lock = lock_ref_sha1_basic(refname, sha1, NULL, NULL, 0, &type, &err);
+ if (!lock) {
+ error("cannot lock ref '%s': %s", refname, err.buf);
+ strbuf_release(&err);
+ return -1;
+ }
if (!reflog_exists(refname)) {
unlock_ref(lock);
return 0;
diff --git a/t/t1400-update-ref.sh b/t/t1400-update-ref.sh
index 636d3a1..ba89f4c 100755
--- a/t/t1400-update-ref.sh
+++ b/t/t1400-update-ref.sh
@@ -519,7 +519,7 @@ test_expect_success 'stdin create ref works with path with space to blob' '
test_expect_success 'stdin update ref fails with wrong old value' '
echo "update $c $m $m~1" >stdin &&
test_must_fail git update-ref --stdin <stdin 2>err &&
- grep "fatal: Cannot lock the ref '"'"'$c'"'"'" err &&
+ grep "fatal: Cannot lock ref '"'"'$c'"'"'" err &&
test_must_fail git rev-parse --verify -q $c
'
@@ -555,7 +555,7 @@ test_expect_success 'stdin update ref works with right old value' '
test_expect_success 'stdin delete ref fails with wrong old value' '
echo "delete $a $m~1" >stdin &&
test_must_fail git update-ref --stdin <stdin 2>err &&
- grep "fatal: Cannot lock the ref '"'"'$a'"'"'" err &&
+ grep "fatal: Cannot lock ref '"'"'$a'"'"'" err &&
git rev-parse $m >expect &&
git rev-parse $a >actual &&
test_cmp expect actual
@@ -688,7 +688,7 @@ test_expect_success 'stdin update refs fails with wrong old value' '
update $c ''
EOF
test_must_fail git update-ref --stdin <stdin 2>err &&
- grep "fatal: Cannot lock the ref '"'"'$c'"'"'" err &&
+ grep "fatal: Cannot lock ref '"'"'$c'"'"'" err &&
git rev-parse $m >expect &&
git rev-parse $a >actual &&
test_cmp expect actual &&
@@ -883,7 +883,7 @@ test_expect_success 'stdin -z create ref works with path with space to blob' '
test_expect_success 'stdin -z update ref fails with wrong old value' '
printf $F "update $c" "$m" "$m~1" >stdin &&
test_must_fail git update-ref -z --stdin <stdin 2>err &&
- grep "fatal: Cannot lock the ref '"'"'$c'"'"'" err &&
+ grep "fatal: Cannot lock ref '"'"'$c'"'"'" err &&
test_must_fail git rev-parse --verify -q $c
'
@@ -899,7 +899,7 @@ test_expect_success 'stdin -z create ref fails when ref exists' '
git rev-parse "$c" >expect &&
printf $F "create $c" "$m~1" >stdin &&
test_must_fail git update-ref -z --stdin <stdin 2>err &&
- grep "fatal: Cannot lock the ref '"'"'$c'"'"'" err &&
+ grep "fatal: Cannot lock ref '"'"'$c'"'"'" err &&
git rev-parse "$c" >actual &&
test_cmp expect actual
'
@@ -930,7 +930,7 @@ test_expect_success 'stdin -z update ref works with right old value' '
test_expect_success 'stdin -z delete ref fails with wrong old value' '
printf $F "delete $a" "$m~1" >stdin &&
test_must_fail git update-ref -z --stdin <stdin 2>err &&
- grep "fatal: Cannot lock the ref '"'"'$a'"'"'" err &&
+ grep "fatal: Cannot lock ref '"'"'$a'"'"'" err &&
git rev-parse $m >expect &&
git rev-parse $a >actual &&
test_cmp expect actual
@@ -1045,7 +1045,7 @@ test_expect_success 'stdin -z update refs fails with wrong old value' '
git update-ref $c $m &&
printf $F "update $a" "$m" "$m" "update $b" "$m" "$m" "update $c" "$m" "$Z" >stdin &&
test_must_fail git update-ref -z --stdin <stdin 2>err &&
- grep "fatal: Cannot lock the ref '"'"'$c'"'"'" err &&
+ grep "fatal: Cannot lock ref '"'"'$c'"'"'" err &&
git rev-parse $m >expect &&
git rev-parse $a >actual &&
test_cmp expect actual &&
diff --git a/t/t1404-update-ref-df-conflicts.sh b/t/t1404-update-ref-df-conflicts.sh
new file mode 100755
index 0000000..66bafb5
--- /dev/null
+++ b/t/t1404-update-ref-df-conflicts.sh
@@ -0,0 +1,107 @@
+#!/bin/sh
+
+test_description='Test git update-ref with D/F conflicts'
+. ./test-lib.sh
+
+test_update_rejected () {
+ prefix="$1" &&
+ before="$2" &&
+ pack="$3" &&
+ create="$4" &&
+ error="$5" &&
+ printf "create $prefix/%s $C\n" $before |
+ git update-ref --stdin &&
+ git for-each-ref $prefix >unchanged &&
+ if $pack
+ then
+ git pack-refs --all
+ fi &&
+ printf "create $prefix/%s $C\n" $create >input &&
+ test_must_fail git update-ref --stdin <input 2>output.err &&
+ grep -F "$error" output.err &&
+ git for-each-ref $prefix >actual &&
+ test_cmp unchanged actual
+}
+
+Q="'"
+
+test_expect_success 'setup' '
+
+ git commit --allow-empty -m Initial &&
+ C=$(git rev-parse HEAD)
+
+'
+
+test_expect_success 'existing loose ref is a simple prefix of new' '
+
+ prefix=refs/1l &&
+ test_update_rejected $prefix "a c e" false "b c/x d" \
+ "$Q$prefix/c$Q exists; cannot create $Q$prefix/c/x$Q"
+
+'
+
+test_expect_success 'existing packed ref is a simple prefix of new' '
+
+ prefix=refs/1p &&
+ test_update_rejected $prefix "a c e" true "b c/x d" \
+ "$Q$prefix/c$Q exists; cannot create $Q$prefix/c/x$Q"
+
+'
+
+test_expect_success 'existing loose ref is a deeper prefix of new' '
+
+ prefix=refs/2l &&
+ test_update_rejected $prefix "a c e" false "b c/x/y d" \
+ "$Q$prefix/c$Q exists; cannot create $Q$prefix/c/x/y$Q"
+
+'
+
+test_expect_success 'existing packed ref is a deeper prefix of new' '
+
+ prefix=refs/2p &&
+ test_update_rejected $prefix "a c e" true "b c/x/y d" \
+ "$Q$prefix/c$Q exists; cannot create $Q$prefix/c/x/y$Q"
+
+'
+
+test_expect_success 'new ref is a simple prefix of existing loose' '
+
+ prefix=refs/3l &&
+ test_update_rejected $prefix "a c/x e" false "b c d" \
+ "$Q$prefix/c/x$Q exists; cannot create $Q$prefix/c$Q"
+
+'
+
+test_expect_success 'new ref is a simple prefix of existing packed' '
+
+ prefix=refs/3p &&
+ test_update_rejected $prefix "a c/x e" true "b c d" \
+ "$Q$prefix/c/x$Q exists; cannot create $Q$prefix/c$Q"
+
+'
+
+test_expect_success 'new ref is a deeper prefix of existing loose' '
+
+ prefix=refs/4l &&
+ test_update_rejected $prefix "a c/x/y e" false "b c d" \
+ "$Q$prefix/c/x/y$Q exists; cannot create $Q$prefix/c$Q"
+
+'
+
+test_expect_success 'new ref is a deeper prefix of existing packed' '
+
+ prefix=refs/4p &&
+ test_update_rejected $prefix "a c/x/y e" true "b c d" \
+ "$Q$prefix/c/x/y$Q exists; cannot create $Q$prefix/c$Q"
+
+'
+
+test_expect_success 'one new ref is a simple prefix of another' '
+
+ prefix=refs/5 &&
+ test_update_rejected $prefix "a e" false "b c c/x d" \
+ "cannot process $Q$prefix/c$Q and $Q$prefix/c/x$Q at the same time"
+
+'
+
+test_done