There are two major ways to check for the existence of a reference in
our tests:
- `git rev-parse --verify` can be used to check for existence of a
reference. This only works in the case where the reference is well
formed though and resolves to an actual object ID. This does not
work with malformed reference names or invalid contents.
- `test_path_is_file` can be used to check for existence of a loose
reference if it is known to not resolve to an actual object ID. It
by necessity reaches into implementation details of the reference
backend though.
Similarly, there are two equivalent ways to check for the absence of a
reference:
- `test_must_fail git rev-parse` can be used to check for the
absence of a reference. It could fail due to a number of reasons
though, and all of these reasons will be thrown into the same bag
as an absent reference.
- `test_path_is_missing` can be used to check explicitly for the
absence of a loose reference, but again reaches into internal
implementation details of the reference backend.
So both our tooling to check for the presence and for the absence of
references in tests is lacking as either failure cases are thrown into
the same bag or we need to reach into internal implementation details of
the respective reference backend.
Introduce a new subcommand for our ref-store test helper that explicitly
checks only for the presence or absence of a reference. This addresses
these limitations:
- We can check for the presence of references with malformed names.
- We can check for the presence of references that don't resolve.
- We can explicitly handle the case where a reference is missing by
special-casing ENOENT errors.
- We don't need to reach into implementation details of the backend,
which would allow us to use this helper for the future reftable
backend.
Next to this subcommand we also provide two wrappers `test_ref_exists`
and `test_ref_missing` that make the helper easier to use.
Signed-off-by: Patrick Steinhardt <ps@xxxxxx>
---
t/README | 9 ++++++
t/helper/test-ref-store.c | 27 +++++++++++++++-
t/test-lib-functions.sh | 66 +++++++++++++++++++++++++++++++++++++++
3 files changed, 101 insertions(+), 1 deletion(-)
diff --git a/t/README b/t/README
index 61080859899..779f7e7dd86 100644
--- a/t/README
+++ b/t/README
@@ -928,6 +928,15 @@ see test-lib-functions.sh for the full list and their options.
committer times to defined state. Subsequent calls will
advance the times by a fixed amount.
+ - test_ref_exists <ref>, test_ref_missing <ref>
+
+ Check whether a reference exists or is missing. In contrast to
+ git-rev-parse(1), these helpers also work with invalid reference
+ names and references whose contents are unresolvable. The latter
+ function also distinguishes generic errors from the case where a
+ reference explicitly doesn't exist and is thus safer to use than
+ `test_must_fail git rev-parse`.
+
- test_commit <message> [<filename> [<contents>]]
Creates a commit with the given message, committing the given
diff --git a/t/helper/test-ref-store.c b/t/helper/test-ref-store.c
index 48552e6a9e0..7400f560ab6 100644
--- a/t/helper/test-ref-store.c
+++ b/t/helper/test-ref-store.c
@@ -1,6 +1,6 @@
#include "test-tool.h"
#include "hex.h"
-#include "refs.h"
+#include "refs/refs-internal.h"
#include "setup.h"
#include "worktree.h"
#include "object-store-ll.h"
@@ -221,6 +221,30 @@ static int cmd_verify_ref(struct ref_store *refs, const char **argv)
return ret;
}
+static int cmd_ref_exists(struct ref_store *refs, const char **argv)
+{
+ const char *refname = notnull(*argv++, "refname");
+ struct strbuf unused_referent = STRBUF_INIT;
+ struct object_id unused_oid;
+ unsigned int unused_type;
+ int failure_errno;
+
+ if (refs_read_raw_ref(refs, refname, &unused_oid, &unused_referent,
+ &unused_type, &failure_errno)) {
+ /*
+ * We handle ENOENT separately here such that it is possible to
+ * distinguish actually-missing references from any kind of
+ * generic error.
+ */
+ if (failure_errno == ENOENT)
+ return 17;
+ return -1;
+ }
+
+ strbuf_release(&unused_referent);
+ return 0;
+}
+
static int cmd_for_each_reflog(struct ref_store *refs,
const char **argv UNUSED)
{
@@ -325,6 +349,7 @@ static struct command commands[] = {
{ "for-each-ref--exclude", cmd_for_each_ref__exclude },
{ "resolve-ref", cmd_resolve_ref },
{ "verify-ref", cmd_verify_ref },
+ { "ref-exists", cmd_ref_exists },
{ "for-each-reflog", cmd_for_each_reflog },
{ "for-each-reflog-ent", cmd_for_each_reflog_ent },
{ "for-each-reflog-ent-reverse", cmd_for_each_reflog_ent_reverse },
diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh
index 2f8868caa17..212fddffa96 100644
--- a/t/test-lib-functions.sh
+++ b/t/test-lib-functions.sh
@@ -251,6 +251,72 @@ debug () {
done
}
+# Usage: test_ref_exists [options] <ref>
+# -C <dir>:
+# Run all git commands in directory <dir>
+# --refdb <refdb>:
+# The reference database to run in. One of:
+# - "main", the main reference database (default).
+# - "submodule:<submodule>", the reference database of a
+# submodule.
+# - "worktree:<worktree>", the reference database for a
+# worktree's per-worktree references.
+#
+# This helper function checks whether a reference exists. Symrefs will not be
+# resolved. Can be used to check references with bad names.
+test_ref_exists () {
+ local indir=
+ local refdb=main
+
+ while test $# != 0
+ do
+ case "$1" in
+ -C)
+ indir="$2"
+ shift
+ ;;
+ --refdb)
+ refdb="$2"
+ shift
+ ;;
+ *)
+ break
+ ;;
+ esac
+ shift
+ done &&
+
+ indir=${indir:+"$indir"/} &&
+
+ if test "$#" != 1
+ then
+ BUG "expected exactly one reference"
+ fi &&
+
+ test-tool ${indir:+ -C "$indir"} ref-store "${refdb}" ref-exists "$1"
+}
+
+# Behaves the same as test_ref_exists, except that it checks for the absence of
+# a reference. This is preferable to `! test_ref_exists` as this function is
+# able to distinguish actually-missing references from other, generic errors.
+test_ref_missing () {
+ test_ref_exists "$@"
+ case "$?" in
+ 17)
+ # This is the good case.
+ return 0
+ ;;
+ 0)
+ echo >&4 "test_ref_missing: reference exists"
+ return 1
+ ;;
+ *)
+ echo >&4 "test_ref_missing: generic error"
+ return 1
+ ;;
+ esac
+}
+
# Usage: test_commit [options] <message> [<file> [<contents> [<tag>]]]
# -C <dir>:
# Run all git commands in directory <dir>
--
2.42.0
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