[PATCH v2 3/5] refs/reftable: add fsck check for number of tables

From

Karthik Nayak <karthik.188@gmail.com>

Date

Sep 2, 2025, 07:05 UTC

Message-ID

<20250902-228-reftable-introduce-consistency-checks-v2-3-4f96b3834779@gmail.com>

In-Reply-To

<20250902-228-reftable-introduce-consistency-checks-v2-0-4f96b3834779@gmail.com>

Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
---
 Documentation/fsck-msgids.adoc |  3 +++
 fsck.h                         |  1 +
 refs/reftable-backend.c        |  3 +++
 reftable/fsck.c                | 34 ++++++++++++++++++++++++++++++++++
 reftable/reftable-fsck.h       |  2 ++
 t/t0614-reftable-fsck.sh       | 20 ++++++++++++++++++++
 6 files changed, 63 insertions(+)

diff --git a/Documentation/fsck-msgids.adoc b/Documentation/fsck-msgids.adoc
index 784ddc0df5..707e2fc50a 100644
--- a/Documentation/fsck-msgids.adoc
+++ b/Documentation/fsck-msgids.adoc
@@ -38,6 +38,9 @@
 `badReferentName`::
 	(ERROR) The referent name of a symref is invalid.
 
+`badReftableStackCount`::
+	(ERROR) Mismatch in number of tables.
+
 `badReftableTableName`::
 	(ERROR) A reftable table has an invalid name.
 
diff --git a/fsck.h b/fsck.h
index 5901f944a1..256effc4f8 100644
--- a/fsck.h
+++ b/fsck.h
@@ -34,6 +34,7 @@ enum fsck_msg_type {
 	FUNC(BAD_PACKED_REF_HEADER, ERROR)                         \
 	FUNC(BAD_PARENT_SHA1, ERROR)                               \
 	FUNC(BAD_REFERENT_NAME, ERROR)                             \
+	FUNC(BAD_REFTABLE_STACK_COUNT, ERROR)                      \
 	FUNC(BAD_REFTABLE_TABLE_NAME, ERROR)                       \
 	FUNC(BAD_REF_CONTENT, ERROR)                               \
 	FUNC(BAD_REF_FILETYPE, ERROR)                              \
diff --git a/refs/reftable-backend.c b/refs/reftable-backend.c
index c38c6422f8..59c39f9b52 100644
--- a/refs/reftable-backend.c
+++ b/refs/reftable-backend.c
@@ -2695,6 +2695,9 @@ static int reftable_fsck_error_handler(struct reftable_fsck_info *info,
 	case REFTABLE_FSCK_ERROR_TABLE_NAME:
 		msg_id = FSCK_MSG_BAD_REFTABLE_TABLE_NAME;
 		break;
+	case REFTABLE_FSCK_ERROR_STACK_COUNT:
+		msg_id = FSCK_MSG_BAD_REFTABLE_STACK_COUNT;
+		break;
 	default:
 		BUG("unknown fsck error: %d", info->error);
 	}
diff --git a/reftable/fsck.c b/reftable/fsck.c
index 4282b1413e..20e6bfb0f1 100644
--- a/reftable/fsck.c
+++ b/reftable/fsck.c
@@ -2,6 +2,28 @@
 #include "reftable-fsck.h"
 #include "stack.h"
 
+static int reftable_fsck_valid_stack_count(struct reftable_stack *st)
+{
+	DIR *dir = opendir(st->reftable_dir);
+	struct dirent *d = NULL;
+	unsigned int count = 0;
+
+	if (!dir)
+		return 0;
+
+	while ((d = readdir(dir))) {
+		if (!strcmp(d->d_name, "tables.list"))
+			continue;
+
+		if (d->d_type == DT_REG)
+			count++;
+	}
+
+	closedir(dir);
+
+	return count == st->tables_len;
+}
+
 int reftable_fsck_check(struct reftable_stack *stack,
 			reftable_fsck_report_fn report_fn,
 			reftable_fsck_verbose_fn verbose_fn,
@@ -47,6 +69,18 @@ int reftable_fsck_check(struct reftable_stack *stack,
 		}
 	}
 
+	verbose_fn("Checking reftable tables count", cb_data);
+
+	if (!reftable_fsck_valid_stack_count(stack)) {
+		struct reftable_fsck_info info = {
+			.error = REFTABLE_FSCK_ERROR_STACK_COUNT,
+			.path = "reftable/tables.list",
+			.msg = "mismatch in number of tables"
+		};
+
+		err = report_fn(&info, cb_data);
+	}
+
 out:
 	free_names(names);
 	return err;
diff --git a/reftable/reftable-fsck.h b/reftable/reftable-fsck.h
index 4cf0053234..beba1bdd1a 100644
--- a/reftable/reftable-fsck.h
+++ b/reftable/reftable-fsck.h
@@ -6,6 +6,8 @@
 enum reftable_fsck_error {
 	/* Invalid table name */
 	REFTABLE_FSCK_ERROR_TABLE_NAME = -1,
+	/* Incorrect number of tables present */
+	REFTABLE_FSCK_ERROR_STACK_COUNT = -2,
 };
 
 /* Represents an individual error encountered during the FSCK checks. */
diff --git a/t/t0614-reftable-fsck.sh b/t/t0614-reftable-fsck.sh
index 81d30df2d7..3a34a31890 100755
--- a/t/t0614-reftable-fsck.sh
+++ b/t/t0614-reftable-fsck.sh
@@ -55,4 +55,24 @@ test_expect_success 'table name should be checked' '
 	)
 '
 
+test_expect_success 'table count should be checked' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+		git commit --allow-empty -m initial &&
+
+		git refs verify 2>err &&
+		test_must_be_empty err &&
+
+		touch .git/reftable/0x000000002812-0x000000002813-c830a596.ref &&
+
+		test_must_fail git refs verify 2>err &&
+		cat >expect <<-EOF &&
+		error: reftable/tables.list: badReftableStackCount: mismatch in number of tables
+		EOF
+		test_cmp expect err
+	)
+'
+
 test_done

-- 
2.50.1