From 466a3a1afdd82bb2b0e24e5cbed1ff3b35c19abd Mon Sep 17 00:00:00 2001
From: Karthik Nayak <karthik.188@gmail.com>
Date: Tue, 7 Oct 2025 14:11:31 +0200
Subject: refs/reftable: add fsck check for checking the table name

Add glue code in 'refs/reftable-backend.c' which calls the reftable
library to perform the fsck checks. Here we also map the reftable errors
to Git' fsck errors.

Introduce a check to validate table names for a given reftable stack.
Also add 'badReftableTableName' as a corresponding error within Git. The
reftable specification mentions:

  It suggested to use
  ${min_update_index}-${max_update_index}-${random}.ref as a naming
  convention.

So treat non-conformant file names as warnings.

While adding the fsck header to 'refs/reftable-backend.c', modify the
list to maintain lexicographical ordering.

Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 t/meson.build            |  1 +
 t/t0614-reftable-fsck.sh | 58 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 59 insertions(+)
 create mode 100755 t/t0614-reftable-fsck.sh

(limited to 't')

diff --git a/t/meson.build b/t/meson.build
index bbeba1a8d5..834e0f1b0a 100644
--- a/t/meson.build
+++ b/t/meson.build
@@ -145,6 +145,7 @@ integration_tests = [
   't0611-reftable-httpd.sh',
   't0612-reftable-jgit-compatibility.sh',
   't0613-reftable-write-options.sh',
+  't0614-reftable-fsck.sh',
   't1000-read-tree-m-3way.sh',
   't1001-read-tree-m-2way.sh',
   't1002-read-tree-m-u-2way.sh',
diff --git a/t/t0614-reftable-fsck.sh b/t/t0614-reftable-fsck.sh
new file mode 100755
index 0000000000..85cc47d67e
--- /dev/null
+++ b/t/t0614-reftable-fsck.sh
@@ -0,0 +1,58 @@
+#!/bin/sh
+
+test_description='Test reftable backend consistency check'
+
+GIT_TEST_DEFAULT_REF_FORMAT=reftable
+export GIT_TEST_DEFAULT_REF_FORMAT
+
+. ./test-lib.sh
+
+test_expect_success "no errors reported on a well formed repository" '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+		git commit --allow-empty -m initial &&
+
+		for i in $(test_seq 20)
+		do
+			git update-ref refs/heads/branch-$i HEAD || return 1
+		done &&
+
+		# The repository should end up with multiple tables.
+		test_line_count ">" 1 .git/reftable/tables.list &&
+
+		git refs verify 2>err &&
+		test_must_be_empty err
+	)
+'
+
+for TABLE_NAME in "foo-bar-e4d12d59.ref" \
+	"0x00000000zzzz-0x00000000zzzz-e4d12d59.ref" \
+	"0x000000000001-0x000000000002-e4d12d59.abc" \
+	"0x000000000001-0x000000000002-e4d12d59.refabc"; do
+	test_expect_success "table name $TABLE_NAME should be checked" '
+		test_when_finished "rm -rf repo" &&
+		git init repo &&
+		(
+			cd repo &&
+			git commit --allow-empty -m initial &&
+
+			git refs verify 2>err &&
+			test_must_be_empty err &&
+
+			EXISTING_TABLE=$(head -n1 .git/reftable/tables.list) &&
+			mv ".git/reftable/$EXISTING_TABLE" ".git/reftable/$TABLE_NAME" &&
+			sed "s/${EXISTING_TABLE}/${TABLE_NAME}/g" .git/reftable/tables.list > tables.list &&
+			mv tables.list .git/reftable/tables.list &&
+
+			git refs verify 2>err &&
+			cat >expect <<-EOF &&
+			warning: ${TABLE_NAME}: badReftableTableName: invalid reftable table name
+			EOF
+			test_cmp expect err
+		)
+	'
+done
+
+test_done
-- 
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