Merge branch 'kn/maintenance-is-needed'

"git maintenance" command learned "is-needed" subcommand to tell if
it is necessary to perform various maintenance tasks.

* kn/maintenance-is-needed:
  maintenance: add 'is-needed' subcommand
  maintenance: add checking logic in `pack_refs_condition()`
  refs: add a `optimize_required` field to `struct ref_storage_be`
  reftable/stack: add function to check if optimization is required
  reftable/stack: return stack segments directly

Documentation/git-maintenance.adoc

@@ -12,6 +12,7 @@ SYNOPSIS
 'git maintenance' run [<options>]
 'git maintenance' start [--scheduler=<scheduler>]
 'git maintenance' (stop|register|unregister) [<options>]
+'git maintenance' is-needed [<options>]
 
 
 DESCRIPTION
@@ -84,6 +85,16 @@ The `unregister` subcommand will report an error if the current repository
 is not already registered. Use the `--force` option to return success even
 when the current repository is not registered.
 
+is-needed::
+    Check whether maintenance needs to be run without actually running it.
+    Exits with a 0 status code if maintenance needs to be run, 1 otherwise.
+    Ideally used with the '--auto' flag.
++
+If one or more `--task` options are specified, then those tasks are checked
+in that order. Otherwise, the tasks are determined by which
+`maintenance.<task>.enabled` config options are true. By default, only
+`maintenance.gc.enabled` is true.
+
 TASKS
 -----
 
@@ -183,6 +194,8 @@ OPTIONS
 	in the `gc.auto` config setting, or when the number of pack-files
 	exceeds the `gc.autoPackLimit` config setting. Not compatible with
 	the `--schedule` option.
+	When combined with the `is-needed` subcommand, check if the required
+	thresholds are met without actually running maintenance.
 
 --schedule::
 	When combined with the `run` subcommand, run maintenance tasks

builtin/gc.c

@@ -36,6 +36,7 @@
 #include "reflog.h"
 #include "repack.h"
 #include "rerere.h"
+#include "revision.h"
 #include "blob.h"
 #include "tree.h"
 #include "promisor-remote.h"
@@ -286,12 +287,26 @@ static void maintenance_run_opts_release(struct maintenance_run_opts *opts)
 
 static int pack_refs_condition(UNUSED struct gc_config *cfg)
 {
-	/*
+	struct string_list included_refs = STRING_LIST_INIT_NODUP;
-	 * The auto-repacking logic for refs is handled by the ref backends and
+	struct ref_exclusions excludes = REF_EXCLUSIONS_INIT;
-	 * exposed via `git pack-refs --auto`. We thus always return truish
+	struct refs_optimize_opts optimize_opts = {
-	 * here and let the backend decide for us.
+		.exclusions = &excludes,
-	 */
+		.includes = &included_refs,
-	return 1;
+		.flags = REFS_OPTIMIZE_PRUNE | REFS_OPTIMIZE_AUTO,
+	};
+	bool required;
+
+	/* Check for all refs, similar to 'git refs optimize --all'. */
+	string_list_append(optimize_opts.includes, "*");
+
+	if (refs_optimize_required(get_main_ref_store(the_repository),
+				   &optimize_opts, &required))
+		return 0;
+
+	clear_ref_exclusions(&excludes);
+	string_list_clear(&included_refs, 0);
+
+	return required;
 }
 
 static int maintenance_task_pack_refs(struct maintenance_run_opts *opts,
@@ -1095,9 +1110,6 @@ static int maintenance_opt_schedule(const struct option *opt, const char *arg,
 	return 0;
 }
 
-/* Remember to update object flag allocation in object.h */
-#define SEEN		(1u<<0)
-
 struct cg_auto_data {
 	int num_not_in_graph;
 	int limit;
@@ -3444,6 +3456,66 @@ static int maintenance_stop(int argc, const char **argv, const char *prefix,
 	return update_background_schedule(NULL, 0);
 }
 
+static const char *const builtin_maintenance_is_needed_usage[] = {
+	"git maintenance is-needed [--task=<task>] [--schedule]",
+	NULL
+};
+
+static int maintenance_is_needed(int argc, const char **argv, const char *prefix,
+				 struct repository *repo UNUSED)
+{
+	struct maintenance_run_opts opts = MAINTENANCE_RUN_OPTS_INIT;
+	struct string_list selected_tasks = STRING_LIST_INIT_DUP;
+	struct gc_config cfg = GC_CONFIG_INIT;
+	struct option options[] = {
+		OPT_BOOL(0, "auto", &opts.auto_flag,
+			 N_("run tasks based on the state of the repository")),
+		OPT_CALLBACK_F(0, "task", &selected_tasks, N_("task"),
+			       N_("check a specific task"),
+			       PARSE_OPT_NONEG, task_option_parse),
+		OPT_END()
+	};
+	bool is_needed = false;
+
+	argc = parse_options(argc, argv, prefix, options,
+			     builtin_maintenance_is_needed_usage,
+			     PARSE_OPT_STOP_AT_NON_OPTION);
+	if (argc)
+		usage_with_options(builtin_maintenance_is_needed_usage, options);
+
+	gc_config(&cfg);
+	initialize_task_config(&opts, &selected_tasks);
+
+	if (opts.auto_flag) {
+		for (size_t i = 0; i < opts.tasks_nr; i++) {
+			if (tasks[opts.tasks[i]].auto_condition &&
+			    tasks[opts.tasks[i]].auto_condition(&cfg)) {
+				is_needed = true;
+				break;
+			}
+		}
+	} else {
+		/*
+		 * When not using --auto we always require maintenance right now.
+		 *
+		 * TODO: this certainly is too eager, as some maintenance tasks may
+		 * decide to not do anything because the data structures are already
+		 * fully optimized. We may eventually want to extend the auto
+		 * condition to also cover non-auto runs so that we can detect such
+		 * cases.
+		 */
+		is_needed = true;
+	}
+
+	string_list_clear(&selected_tasks, 0);
+	maintenance_run_opts_release(&opts);
+	gc_config_release(&cfg);
+
+	if (is_needed)
+		return 0;
+	return 1;
+}
+
 static const char *const builtin_maintenance_usage[] = {
 	N_("git maintenance <subcommand> [<options>]"),
 	NULL,
@@ -3461,6 +3533,7 @@ int cmd_maintenance(int argc,
 		OPT_SUBCOMMAND("stop", &fn, maintenance_stop),
 		OPT_SUBCOMMAND("register", &fn, maintenance_register),
 		OPT_SUBCOMMAND("unregister", &fn, maintenance_unregister),
+		OPT_SUBCOMMAND("is-needed", &fn, maintenance_is_needed),
 		OPT_END(),
 	};
 

object.h

@@ -80,7 +80,6 @@ void object_array_init(struct object_array *array);
  * list-objects-filter.c:                                      21
  * bloom.c:                                                    2122
  * builtin/fsck.c:           0--3
- * builtin/gc.c:             0
  * builtin/index-pack.c:                                     2021
  * reflog.c:                           10--12
  * builtin/show-branch.c:    0-------------------------------------------26

refs.c

@@ -2318,6 +2318,13 @@ int refs_optimize(struct ref_store *refs, struct refs_optimize_opts *opts)
 	return refs->be->optimize(refs, opts);
 }
 
+int refs_optimize_required(struct ref_store *refs,
+			   struct refs_optimize_opts *opts,
+			   bool *required)
+{
+	return refs->be->optimize_required(refs, opts, required);
+}
+
 int reference_get_peeled_oid(struct repository *repo,
 			     const struct reference *ref,
 			     struct object_id *peeled_oid)

refs.h

@@ -520,6 +520,13 @@ struct refs_optimize_opts {
  */
 int refs_optimize(struct ref_store *refs, struct refs_optimize_opts *opts);
 
+/*
+ * Check if refs backend can be optimized by calling 'refs_optimize'.
+ */
+int refs_optimize_required(struct ref_store *ref_store,
+			   struct refs_optimize_opts *opts,
+			   bool *required);
+
 /*
  * Setup reflog before using. Fill in err and return -1 on failure.
  */

refs/debug.c

@@ -132,6 +132,17 @@ static int debug_optimize(struct ref_store *ref_store, struct refs_optimize_opts
 	return res;
 }
 
+static int debug_optimize_required(struct ref_store *ref_store,
+				   struct refs_optimize_opts *opts,
+				   bool *required)
+{
+	struct debug_ref_store *drefs = (struct debug_ref_store *)ref_store;
+	int res = drefs->refs->be->optimize_required(drefs->refs, opts, required);
+	trace_printf_key(&trace_refs, "optimize_required: %s, res: %d\n",
+			 required ? "yes" : "no", res);
+	return res;
+}
+
 static int debug_rename_ref(struct ref_store *ref_store, const char *oldref,
 			    const char *newref, const char *logmsg)
 {
@@ -440,6 +451,8 @@ struct ref_storage_be refs_be_debug = {
 	.transaction_abort = debug_transaction_abort,
 
 	.optimize = debug_optimize,
+	.optimize_required = debug_optimize_required,
+
 	.rename_ref = debug_rename_ref,
 	.copy_ref = debug_copy_ref,
 

refs/files-backend.c

@@ -1512,6 +1512,16 @@ static int files_optimize(struct ref_store *ref_store,
 	return 0;
 }
 
+static int files_optimize_required(struct ref_store *ref_store,
+				   struct refs_optimize_opts *opts,
+				   bool *required)
+{
+	struct files_ref_store *refs = files_downcast(ref_store, REF_STORE_READ,
+						      "optimize_required");
+	*required = should_pack_refs(refs, opts);
+	return 0;
+}
+
 /*
  * People using contrib's git-new-workdir have .git/logs/refs ->
  * /some/other/path/.git/logs/refs, and that may live on another device.
@@ -3982,6 +3992,7 @@ struct ref_storage_be refs_be_files = {
 	.transaction_abort = files_transaction_abort,
 
 	.optimize = files_optimize,
+	.optimize_required = files_optimize_required,
 	.rename_ref = files_rename_ref,
 	.copy_ref = files_copy_ref,
 

refs/packed-backend.c

@@ -1784,6 +1784,17 @@ static int packed_optimize(struct ref_store *ref_store UNUSED,
 	return 0;
 }
 
+static int packed_optimize_required(struct ref_store *ref_store UNUSED,
+				    struct refs_optimize_opts *opts UNUSED,
+				    bool *required)
+{
+	/*
+	 * Packed refs are already optimized.
+	 */
+	*required = false;
+	return 0;
+}
+
 static struct ref_iterator *packed_reflog_iterator_begin(struct ref_store *ref_store UNUSED)
 {
 	return empty_ref_iterator_begin();
@@ -2130,6 +2141,8 @@ struct ref_storage_be refs_be_packed = {
 	.transaction_abort = packed_transaction_abort,
 
 	.optimize = packed_optimize,
+	.optimize_required = packed_optimize_required,
+
 	.rename_ref = NULL,
 	.copy_ref = NULL,
 

refs/refs-internal.h

@@ -424,6 +424,11 @@ typedef int ref_transaction_commit_fn(struct ref_store *refs,
 
 typedef int optimize_fn(struct ref_store *ref_store,
 			struct refs_optimize_opts *opts);
+
+typedef int optimize_required_fn(struct ref_store *ref_store,
+				 struct refs_optimize_opts *opts,
+				 bool *required);
+
 typedef int rename_ref_fn(struct ref_store *ref_store,
 			  const char *oldref, const char *newref,
 			  const char *logmsg);
@@ -549,6 +554,7 @@ struct ref_storage_be {
 	ref_transaction_abort_fn *transaction_abort;
 
 	optimize_fn *optimize;
+	optimize_required_fn *optimize_required;
 	rename_ref_fn *rename_ref;
 	copy_ref_fn *copy_ref;
 

refs/reftable-backend.c

@@ -1733,6 +1733,29 @@ out:
 	return ret;
 }
 
+static int reftable_be_optimize_required(struct ref_store *ref_store,
+					 struct refs_optimize_opts *opts,
+					 bool *required)
+{
+	struct reftable_ref_store *refs = reftable_be_downcast(ref_store, REF_STORE_READ,
+							       "optimize_refs_required");
+	struct reftable_stack *stack;
+	bool use_heuristics = false;
+
+	if (refs->err)
+		return refs->err;
+
+	stack = refs->worktree_backend.stack;
+	if (!stack)
+		stack = refs->main_backend.stack;
+
+	if (opts->flags & REFS_OPTIMIZE_AUTO)
+		use_heuristics = true;
+
+	return reftable_stack_compaction_required(stack, use_heuristics,
+						  required);
+}
+
 struct write_create_symref_arg {
 	struct reftable_ref_store *refs;
 	struct reftable_stack *stack;
@@ -2756,6 +2779,8 @@ struct ref_storage_be refs_be_reftable = {
 	.transaction_abort = reftable_be_transaction_abort,
 
 	.optimize = reftable_be_optimize,
+	.optimize_required = reftable_be_optimize_required,
+
 	.rename_ref = reftable_be_rename_ref,
 	.copy_ref = reftable_be_copy_ref,
 

reftable/reftable-stack.h

@@ -123,6 +123,17 @@ struct reftable_log_expiry_config {
 int reftable_stack_compact_all(struct reftable_stack *st,
 			       struct reftable_log_expiry_config *config);
 
+/*
+ * Check if compaction is required.
+ *
+ * When `use_heuristics` is false, check if all tables can be compacted to a
+ * single table. If true, use heuristics to determine if the tables need to be
+ * compacted to maintain geometric progression.
+ */
+int reftable_stack_compaction_required(struct reftable_stack *st,
+				       bool use_heuristics,
+				       bool *required);
+
 /* heuristically compact unbalanced table stack. */
 int reftable_stack_auto_compact(struct reftable_stack *st);
 

reftable/stack.c

@@ -1626,7 +1626,8 @@ struct segment suggest_compaction_segment(uint64_t *sizes, size_t n,
 	return seg;
 }
 
-static uint64_t *stack_table_sizes_for_compaction(struct reftable_stack *st)
+static int stack_segments_for_compaction(struct reftable_stack *st,
+					 struct segment *seg)
 {
 	int version = (st->opts.hash_id == REFTABLE_HASH_SHA1) ? 1 : 2;
 	int overhead = header_size(version) - 1;
@@ -1634,31 +1635,63 @@ static uint64_t *stack_table_sizes_for_compaction(struct reftable_stack *st)
 
 	REFTABLE_CALLOC_ARRAY(sizes, st->merged->tables_len);
 	if (!sizes)
-		return NULL;
+		return REFTABLE_OUT_OF_MEMORY_ERROR;
 
 	for (size_t i = 0; i < st->merged->tables_len; i++)
 		sizes[i] = st->tables[i]->size - overhead;
 
-	return sizes;
+	*seg = suggest_compaction_segment(sizes, st->merged->tables_len,
+					  st->opts.auto_compaction_factor);
+	reftable_free(sizes);
+
+	return 0;
+}
+
+static int update_segment_if_compaction_required(struct reftable_stack *st,
+						 struct segment *seg,
+						 bool use_geometric,
+						 bool *required)
+{
+	int err;
+
+	if (st->merged->tables_len < 2) {
+		*required = false;
+		return 0;
+	}
+
+	if (!use_geometric) {
+		*required = true;
+		return 0;
+	}
+
+	err = stack_segments_for_compaction(st, seg);
+	if (err)
+		return err;
+
+	*required = segment_size(seg) > 0;
+	return 0;
+}
+
+int reftable_stack_compaction_required(struct reftable_stack *st,
+				       bool use_heuristics,
+				       bool *required)
+{
+	struct segment seg;
+	return update_segment_if_compaction_required(st, &seg, use_heuristics,
+						     required);
 }
 
 int reftable_stack_auto_compact(struct reftable_stack *st)
 {
 	struct segment seg;
-	uint64_t *sizes;
+	bool required;
+	int err;
 
-	if (st->merged->tables_len < 2)
+	err = update_segment_if_compaction_required(st, &seg, true, &required);
-		return 0;
+	if (err)
+		return err;
 
-	sizes = stack_table_sizes_for_compaction(st);
+	if (required)
-	if (!sizes)
-		return REFTABLE_OUT_OF_MEMORY_ERROR;
-
-	seg = suggest_compaction_segment(sizes, st->merged->tables_len,
-					 st->opts.auto_compaction_factor);
-	reftable_free(sizes);
-
-	if (segment_size(&seg) > 0)
 		return stack_compact_range(st, seg.start, seg.end - 1,
 					   NULL, STACK_COMPACT_RANGE_BEST_EFFORT);
 

t/t7900-maintenance.sh

@@ -49,7 +49,9 @@ test_expect_success 'run [--auto|--quiet]' '
 		git maintenance run --auto 2>/dev/null &&
 	GIT_TRACE2_EVENT="$(pwd)/run-no-quiet.txt" \
 		git maintenance run --no-quiet 2>/dev/null &&
+	git maintenance is-needed &&
 	test_subcommand git gc --quiet --no-detach --skip-foreground-tasks <run-no-auto.txt &&
+	! git maintenance is-needed --auto &&
 	test_subcommand ! git gc --auto --quiet --no-detach --skip-foreground-tasks <run-auto.txt &&
 	test_subcommand git gc --no-quiet --no-detach --skip-foreground-tasks <run-no-quiet.txt
 '
@@ -180,6 +182,11 @@ test_expect_success 'commit-graph auto condition' '
 
 	test_commit first &&
 
+	! git -c maintenance.commit-graph.auto=0 \
+		maintenance is-needed --auto --task=commit-graph &&
+	git -c maintenance.commit-graph.auto=1 \
+		maintenance is-needed --auto --task=commit-graph &&
+
 	GIT_TRACE2_EVENT="$(pwd)/cg-zero-means-no.txt" \
 		git -c maintenance.commit-graph.auto=0 $COMMAND &&
 	GIT_TRACE2_EVENT="$(pwd)/cg-one-satisfied.txt" \
@@ -290,16 +297,23 @@ test_expect_success 'maintenance.loose-objects.auto' '
 		git -c maintenance.loose-objects.auto=1 maintenance \
 		run --auto --task=loose-objects 2>/dev/null &&
 	test_subcommand ! git prune-packed --quiet <trace-lo1.txt &&
+
 	printf data-A | git hash-object -t blob --stdin -w &&
+	! git -c maintenance.loose-objects.auto=2 \
+		maintenance is-needed --auto --task=loose-objects &&
 	GIT_TRACE2_EVENT="$(pwd)/trace-loA" \
 		git -c maintenance.loose-objects.auto=2 \
 		maintenance run --auto --task=loose-objects 2>/dev/null &&
 	test_subcommand ! git prune-packed --quiet <trace-loA &&
+
 	printf data-B | git hash-object -t blob --stdin -w &&
+	git -c maintenance.loose-objects.auto=2 \
+		maintenance is-needed --auto --task=loose-objects &&
 	GIT_TRACE2_EVENT="$(pwd)/trace-loB" \
 		git -c maintenance.loose-objects.auto=2 \
 		maintenance run --auto --task=loose-objects 2>/dev/null &&
 	test_subcommand git prune-packed --quiet <trace-loB &&
+
 	GIT_TRACE2_EVENT="$(pwd)/trace-loC" \
 		git -c maintenance.loose-objects.auto=2 \
 		maintenance run --auto --task=loose-objects 2>/dev/null &&
@@ -421,10 +435,13 @@ run_incremental_repack_and_verify () {
 	test_commit A &&
 	git repack -adk &&
 	git multi-pack-index write &&
+	! git -c maintenance.incremental-repack.auto=1 \
+		maintenance is-needed --auto --task=incremental-repack &&
 	GIT_TRACE2_EVENT="$(pwd)/midx-init.txt" git \
 		-c maintenance.incremental-repack.auto=1 \
 		maintenance run --auto --task=incremental-repack 2>/dev/null &&
 	test_subcommand ! git multi-pack-index write --no-progress <midx-init.txt &&
+
 	test_commit B &&
 	git pack-objects --revs .git/objects/pack/pack <<-\EOF &&
 	HEAD
@@ -434,11 +451,14 @@ run_incremental_repack_and_verify () {
 		-c maintenance.incremental-repack.auto=2 \
 		maintenance run --auto --task=incremental-repack 2>/dev/null &&
 	test_subcommand ! git multi-pack-index write --no-progress <trace-A &&
+
 	test_commit C &&
 	git pack-objects --revs .git/objects/pack/pack <<-\EOF &&
 	HEAD
 	^HEAD~1
 	EOF
+	git -c maintenance.incremental-repack.auto=2 \
+		maintenance is-needed --auto --task=incremental-repack &&
 	GIT_TRACE2_EVENT=$(pwd)/trace-B git \
 		-c maintenance.incremental-repack.auto=2 \
 		maintenance run --auto --task=incremental-repack 2>/dev/null &&
@@ -655,9 +675,15 @@ test_expect_success 'reflog-expire task --auto only packs when exceeding limits'
 	git reflog expire --all --expire=now &&
 	test_commit reflog-one &&
 	test_commit reflog-two &&
+
+	! git -c maintenance.reflog-expire.auto=3 \
+		maintenance is-needed --auto --task=reflog-expire &&
 	GIT_TRACE2_EVENT="$(pwd)/reflog-expire-auto.txt" \
 		git -c maintenance.reflog-expire.auto=3 maintenance run --auto --task=reflog-expire &&
 	test_subcommand ! git reflog expire --all <reflog-expire-auto.txt &&
+
+	git -c maintenance.reflog-expire.auto=2 \
+		maintenance is-needed --auto --task=reflog-expire &&
 	GIT_TRACE2_EVENT="$(pwd)/reflog-expire-auto.txt" \
 		git -c maintenance.reflog-expire.auto=2 maintenance run --auto --task=reflog-expire &&
 	test_subcommand git reflog expire --all <reflog-expire-auto.txt
@@ -684,6 +710,7 @@ test_expect_success 'worktree-prune task --auto only prunes with prunable worktr
 	test_expect_worktree_prune ! git maintenance run --auto --task=worktree-prune &&
 	mkdir .git/worktrees &&
 	: >.git/worktrees/abc &&
+	git maintenance is-needed --auto --task=worktree-prune &&
 	test_expect_worktree_prune git maintenance run --auto --task=worktree-prune
 '
 
@@ -700,22 +727,7 @@ test_expect_success 'worktree-prune task with --auto honors maintenance.worktree
 	test_expect_worktree_prune ! git -c maintenance.worktree-prune.auto=0 maintenance run --auto --task=worktree-prune &&
 	# A positive value should require at least this many prunable worktrees.
 	test_expect_worktree_prune ! git -c maintenance.worktree-prune.auto=4 maintenance run --auto --task=worktree-prune &&
-	test_expect_worktree_prune git -c maintenance.worktree-prune.auto=3 maintenance run --auto --task=worktree-prune
+	git -c maintenance.worktree-prune.auto=3 maintenance is-needed --auto --task=worktree-prune &&
-'
-
-test_expect_success 'worktree-prune task with --auto honors maintenance.worktree-prune.auto' '
-	# A negative value should always prune.
-	test_expect_worktree_prune git -c maintenance.worktree-prune.auto=-1 maintenance run --auto --task=worktree-prune &&
-
-	mkdir .git/worktrees &&
-	: >.git/worktrees/first &&
-	: >.git/worktrees/second &&
-	: >.git/worktrees/third &&
-
-	# Zero should never prune.
-	test_expect_worktree_prune ! git -c maintenance.worktree-prune.auto=0 maintenance run --auto --task=worktree-prune &&
-	# A positive value should require at least this many prunable worktrees.
-	test_expect_worktree_prune ! git -c maintenance.worktree-prune.auto=4 maintenance run --auto --task=worktree-prune &&
 	test_expect_worktree_prune git -c maintenance.worktree-prune.auto=3 maintenance run --auto --task=worktree-prune
 '
 
@@ -724,11 +736,13 @@ test_expect_success 'worktree-prune task honors gc.worktreePruneExpire' '
 	rm -rf worktree &&
 
 	rm -f worktree-prune.txt &&
+	! git -c gc.worktreePruneExpire=1.week.ago maintenance is-needed --auto --task=worktree-prune &&
 	GIT_TRACE2_EVENT="$(pwd)/worktree-prune.txt" git -c gc.worktreePruneExpire=1.week.ago maintenance run --auto --task=worktree-prune &&
 	test_subcommand ! git worktree prune --expire 1.week.ago <worktree-prune.txt &&
 	test_path_is_dir .git/worktrees/worktree &&
 
 	rm -f worktree-prune.txt &&
+	git -c gc.worktreePruneExpire=now maintenance is-needed --auto --task=worktree-prune &&
 	GIT_TRACE2_EVENT="$(pwd)/worktree-prune.txt" git -c gc.worktreePruneExpire=now maintenance run --auto --task=worktree-prune &&
 	test_subcommand git worktree prune --expire now <worktree-prune.txt &&
 	test_path_is_missing .git/worktrees/worktree
@@ -753,10 +767,13 @@ test_expect_success 'rerere-gc task without --auto always collects garbage' '
 
 test_expect_success 'rerere-gc task with --auto only prunes with prunable entries' '
 	test_when_finished "rm -rf .git/rr-cache" &&
+	! git maintenance is-needed --auto --task=rerere-gc &&
 	test_expect_rerere_gc ! git maintenance run --auto --task=rerere-gc &&
 	mkdir .git/rr-cache &&
+	! git maintenance is-needed --auto --task=rerere-gc &&
 	test_expect_rerere_gc ! git maintenance run --auto --task=rerere-gc &&
 	: >.git/rr-cache/entry &&
+	git maintenance is-needed --auto --task=rerere-gc &&
 	test_expect_rerere_gc git maintenance run --auto --task=rerere-gc
 '
 
@@ -764,17 +781,22 @@ test_expect_success 'rerere-gc task with --auto honors maintenance.rerere-gc.aut
 	test_when_finished "rm -rf .git/rr-cache" &&
 
 	# A negative value should always prune.
+	git -c maintenance.rerere-gc.auto=-1 maintenance is-needed --auto --task=rerere-gc &&
 	test_expect_rerere_gc git -c maintenance.rerere-gc.auto=-1 maintenance run --auto --task=rerere-gc &&
 
 	# A positive value prunes when there is at least one entry.
+	! git -c maintenance.rerere-gc.auto=9000 maintenance is-needed --auto --task=rerere-gc &&
 	test_expect_rerere_gc ! git -c maintenance.rerere-gc.auto=9000 maintenance run --auto --task=rerere-gc &&
 	mkdir .git/rr-cache &&
+	! git -c maintenance.rerere-gc.auto=9000 maintenance is-needed --auto --task=rerere-gc &&
 	test_expect_rerere_gc ! git -c maintenance.rerere-gc.auto=9000 maintenance run --auto --task=rerere-gc &&
 	: >.git/rr-cache/entry-1 &&
+	git -c maintenance.rerere-gc.auto=9000 maintenance is-needed --auto --task=rerere-gc &&
 	test_expect_rerere_gc git -c maintenance.rerere-gc.auto=9000 maintenance run --auto --task=rerere-gc &&
 
 	# Zero should never prune.
 	: >.git/rr-cache/entry-1 &&
+	! git -c maintenance.rerere-gc.auto=0 maintenance is-needed --auto --task=rerere-gc &&
 	test_expect_rerere_gc ! git -c maintenance.rerere-gc.auto=0 maintenance run --auto --task=rerere-gc
 '
 

t/unit-tests/u-reftable-stack.c

@@ -1067,6 +1067,7 @@ void test_reftable_stack__add_performs_auto_compaction(void)
 			.value_type = REFTABLE_REF_SYMREF,
 			.value.symref = (char *) "master",
 		};
+		bool required = false;
 		char buf[128];
 
 		/*
@@ -1087,10 +1088,17 @@ void test_reftable_stack__add_performs_auto_compaction(void)
 		 * auto compaction is disabled. When enabled, we should merge
 		 * all tables in the stack.
 		 */
-		if (i != n)
+		cl_assert_equal_i(reftable_stack_compaction_required(st, true, &required), 0);
+		if (i != n) {
 			cl_assert_equal_i(st->merged->tables_len, i + 1);
+			if (i < 1)
+				cl_assert_equal_b(required, false);
 			else
+				cl_assert_equal_b(required, true);
+		} else {
 			cl_assert_equal_i(st->merged->tables_len, 1);
+			cl_assert_equal_b(required, false);
+		}
 	}
 
 	reftable_stack_destroy(st);