[PATCH v3 15/20] maintenance: use pointers to check --auto

["Derrick Stolee via GitGitGadget" <gitgitgadget@gmail.com>]

From: Derrick Stolee <dstolee@microsoft.com>

The 'git maintenance run' command has an '--auto' option. This is used
by other Git commands such as 'git commit' or 'git fetch' to check if
maintenance should be run after adding data to the repository.

Previously, this --auto option was only used to add the argument to the
'git gc' command as part of the 'gc' task. We will be expanding the
other tasks to perform a check to see if they should do work as part of
the --auto flag, when they are enabled by config.

First, update the 'gc' task to perform the auto check inside the
maintenance process. This prevents running an extra 'git gc --auto'
command when not needed. It also shows a model for other tasks.

Second, use the 'auto_condition' function pointer as a signal for
whether we enable the maintenance task under '--auto'. For instance, we
do not want to enable the 'fetch' task in '--auto' mode, so that
function pointer will remain NULL.

Now that we are not automatically calling 'git gc', a test in
t5514-fetch-multiple.sh must be changed to watch for 'git maintenance'
instead.

We continue to pass the '--auto' option to the 'git gc' command when
necessary, because of the gc.autoDetach config option changes behavior.
Likely, we will want to absorb the daemonizing behavior implied by
gc.autoDetach as a maintenance.autoDetach config option.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
---
 builtin/gc.c              | 16 ++++++++++++++++
 t/t5514-fetch-multiple.sh |  2 +-
 t/t7900-maintenance.sh    |  2 +-
 3 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/builtin/gc.c b/builtin/gc.c
index c599690591..1c449b3776 100644
--- a/builtin/gc.c
+++ b/builtin/gc.c
@@ -1074,9 +1074,17 @@ static int maintenance_task_incremental_repack(void)
 
 typedef int maintenance_task_fn(void);
 
+/*
+ * An auto condition function returns 1 if the task should run
+ * and 0 if the task should NOT run. See needs_to_gc() for an
+ * example.
+ */
+typedef int maintenance_auto_fn(void);
+
 struct maintenance_task {
 	const char *name;
 	maintenance_task_fn *fn;
+	maintenance_auto_fn *auto_condition;
 	unsigned enabled:1,
 		 selected:1;
 	int selected_order;
@@ -1109,6 +1117,7 @@ static struct maintenance_task tasks[] = {
 	[TASK_GC] = {
 		"gc",
 		maintenance_task_gc,
+		need_to_gc,
 		1,
 	},
 	[TASK_COMMIT_GRAPH] = {
@@ -1161,6 +1170,11 @@ static int maintenance_run(void)
 		if (!opts.tasks_selected && !tasks[i].enabled)
 			continue;
 
+		if (opts.auto_flag &&
+		    (!tasks[i].auto_condition ||
+		     !tasks[i].auto_condition()))
+			continue;
+
 		if (tasks[i].fn()) {
 			error(_("task '%s' failed"), tasks[i].name);
 			result = 1;
@@ -1175,6 +1189,8 @@ static void initialize_task_config(void)
 {
 	int i;
 	struct strbuf config_name = STRBUF_INIT;
+	gc_config();
+
 	for (i = 0; i < TASK__COUNT; i++) {
 		int config_value;
 
diff --git a/t/t5514-fetch-multiple.sh b/t/t5514-fetch-multiple.sh
index de8e2f1531..bd202ec6f3 100755
--- a/t/t5514-fetch-multiple.sh
+++ b/t/t5514-fetch-multiple.sh
@@ -108,7 +108,7 @@ test_expect_success 'git fetch --multiple (two remotes)' '
 	 GIT_TRACE=1 git fetch --multiple one two 2>trace &&
 	 git branch -r > output &&
 	 test_cmp ../expect output &&
-	 grep "built-in: git gc" trace >gc &&
+	 grep "built-in: git maintenance" trace >gc &&
 	 test_line_count = 1 gc
 	)
 '
diff --git a/t/t7900-maintenance.sh b/t/t7900-maintenance.sh
index affa268dec..19494e6c43 100755
--- a/t/t7900-maintenance.sh
+++ b/t/t7900-maintenance.sh
@@ -17,7 +17,7 @@ test_expect_success 'run [--auto|--quiet]' '
 	GIT_TRACE2_EVENT="$(pwd)/run-auto.txt" git maintenance run --auto &&
 	GIT_TRACE2_EVENT="$(pwd)/run-quiet.txt" git maintenance run --quiet &&
 	grep ",\"gc\"]" run-no-auto.txt  &&
-	grep ",\"gc\",\"--auto\"" run-auto.txt &&
+	! grep ",\"gc\",\"--auto\"" run-auto.txt &&
 	grep ",\"gc\",\"--quiet\"" run-quiet.txt
 '
 
-- 
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