[PATCH 11/12] gc + reflog: emit progress output from "reflog expire --all"

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

Emit progress output on "git reflog expire --all", which is what "git
gc" runs. On my git.git checkout I'll now get:

    $ time GIT_PROGRESS_DELAY=0 ~/g/git/git reflog expire --all --dry-run
    Enumerating reflogs: 23782, done.
    Expiring reflogs: 100% (23782/23782), done.

    real    0m3.264s
    user    0m2.308s
    sys     0m0.941s

The "Enumerating reflogs" is too fast to appear for me except with
GIT_PROGRESS_DELAY=0. We'll also emit this at the top of "git gc"
output:

    $ ~/g/git/git --exec-path=$PWD gc
    Expiring reflogs: 100% (23782/23782), done.
    Enumerating objects: [...]

This goes a long way (but not quite, a subsequent commit will) to
addressing the seeming halting of "git gc" on startup. That usually
happens because of the "HEAD" case in "reflog expire --all" and
unreachable().

Note that this code isn't going to be affected by the sort of bug we
had to fix in 6b89a34c89f (gc: fix regression in 7b0f229222 impacting
--quiet, 2018-09-19).

This is because "git gc" even with "--auto" won't detach until after
it runs "git reflog -expire", so whatever output we emit will never
end up in the gc.log. We should still obey its --quiet to mean our
--no-progress, but we don't need a special-case for "daemonized" as
write_commit_graph_reachable() does.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 builtin/gc.c     |  4 +++-
 builtin/reflog.c | 19 ++++++++++++++++++-
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/builtin/gc.c b/builtin/gc.c
index bcef6a4c8da..872209e083e 100644
--- a/builtin/gc.c
+++ b/builtin/gc.c
@@ -593,8 +593,10 @@ int cmd_gc(int argc, const char **argv, const char *prefix)
 		if (aggressive_window > 0)
 			strvec_pushf(&repack, "--window=%d", aggressive_window);
 	}
-	if (quiet)
+	if (quiet) {
+		strvec_push(&reflog, "--no-progress");
 		strvec_push(&repack, "-q");
+	}
 
 	if (auto_gc) {
 		/*
diff --git a/builtin/reflog.c b/builtin/reflog.c
index cf0ef68d82d..1a2a210ecf1 100644
--- a/builtin/reflog.c
+++ b/builtin/reflog.c
@@ -53,6 +53,7 @@ struct expire_reflog_policy_cb {
 struct worktree_reflogs {
 	struct worktree *worktree;
 	struct string_list reflogs;
+	struct progress *progress;
 };
 
 /* Remember to update object flag allocation in object.h */
@@ -324,7 +325,7 @@ static int should_expire_reflog_ent(struct object_id *ooid, struct object_id *no
 
 	return 0;
 expire:
-	if (cb->dry_run)
+	if (cb->verbose && cb->dry_run)
 		printf("would prune %s", message);
 	else if (cb->verbose)
 		printf("prune %s", message);
@@ -426,6 +427,7 @@ static int collect_reflog(const char *ref, const struct object_id *oid, int unus
 	if (!worktree->is_current && ref_type(ref) == REF_TYPE_NORMAL)
 		return 0;
 
+	display_progress(cb->progress, cb->reflogs.nr + 1);
 	strbuf_worktree_ref(worktree, &newref, ref);
 	string_list_append(&cb->reflogs, strbuf_detach(&newref, NULL));
 
@@ -627,11 +629,17 @@ static int cmd_reflog_expire(int argc, const char **argv, const char *prefix)
 	}
 
 	if (do_all) {
+		struct progress *progress = NULL;
 		struct worktree_reflogs collected = {
 			.reflogs = STRING_LIST_INIT_NODUP,
 		};
 		struct string_list_item *item;
 		struct worktree **worktrees, **p;
+		uint64_t progress_cnt;
+
+		if (show_progress)
+			collected.progress = start_delayed_progress(_("Enumerating reflogs"),
+								    0);
 
 		worktrees = get_worktrees();
 		for (p = worktrees; *p; p++) {
@@ -642,6 +650,13 @@ static int cmd_reflog_expire(int argc, const char **argv, const char *prefix)
 					     collect_reflog, &collected);
 		}
 		free_worktrees(worktrees);
+		stop_progress(&collected.progress);
+
+		if (show_progress) {
+			progress_cnt = 0;
+			progress = start_delayed_progress(_("Expiring reflogs"),
+							  collected.reflogs.nr);
+		}
 
 		for_each_string_list_item(item, &collected.reflogs) {
 			struct expire_reflog_policy_cb cb = {
@@ -650,6 +665,7 @@ static int cmd_reflog_expire(int argc, const char **argv, const char *prefix)
 				.verbose = verbose,
 			};
 
+			display_progress(progress, ++progress_cnt);
 			set_reflog_expiry_param(&cb.cmd, explicit_expiry, item->string);
 			status |= reflog_expire(item->string, flags,
 						reflog_expiry_prepare,
@@ -657,6 +673,7 @@ static int cmd_reflog_expire(int argc, const char **argv, const char *prefix)
 						reflog_expiry_cleanup,
 						&cb);
 		}
+		stop_progress(&progress);
 		collected.reflogs.strdup_strings = 1;
 		string_list_clear(&collected.reflogs, 0);
 	}
-- 
2.34.1.877.g7d5b0a3b8a6