From cdbd70c43773d534aa81ea2c83905a45ff0e74e4 Mon Sep 17 00:00:00 2001
From: Derrick Stolee <dstolee@microsoft.com>
Date: Tue, 18 Jun 2019 13:25:26 -0700
Subject: fetch: add --[no-]show-forced-updates argument

After updating a set of remove refs during a 'git fetch', we walk the
commits in the new ref value and not in the old ref value to discover
if the update was a forced update. This results in two things happening
during the command:

 1. The line including the ref update has an additional "(forced-update)"
    marker at the end.

 2. The ref log for that remote branch includes a bit saying that update
    is a forced update.

For many situations, this forced-update message happens infrequently, or
is a small bit of information among many ref updates. Many users ignore
these messages, but the calculation required here slows down their fetches
significantly. Keep in mind that they do not have the opportunity to
calculate a commit-graph file containing the newly-fetched commits, so
these comparisons can be very slow.

Add a '--[no-]show-forced-updates' option that allows a user to skip this
calculation. The only permanent result is dropping the forced-update bit
in the reflog.

Include a new fetch.showForcedUpdates config setting that allows this
behavior without including the argument in every command. The config
setting is overridden by the command-line arguments.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/config/fetch.txt b/Documentation/config/fetch.txt
index cbfad6c..ba890b5 100644
--- a/Documentation/config/fetch.txt
+++ b/Documentation/config/fetch.txt
@@ -63,3 +63,8 @@ fetch.negotiationAlgorithm::
 	Unknown values will cause 'git fetch' to error out.
 +
 See also the `--negotiation-tip` option for linkgit:git-fetch[1].
+
+fetch.showForcedUpdates::
+	Set to false to enable `--no-show-forced-updates` in
+	linkgit:git-fetch[1] and linkgit:git-pull[1] commands.
+	Defaults to true.
diff --git a/Documentation/fetch-options.txt b/Documentation/fetch-options.txt
index 91c4775..5801d23 100644
--- a/Documentation/fetch-options.txt
+++ b/Documentation/fetch-options.txt
@@ -221,6 +221,19 @@ endif::git-pull[]
 	When multiple `--server-option=<option>` are given, they are all
 	sent to the other side in the order listed on the command line.
 
+--show-forced-updates::
+	By default, git checks if a branch is force-updated during
+	fetch. This can be disabled through fetch.showForcedUpdates, but
+	the --show-forced-updates option guarantees this check occurs.
+	See linkgit:git-config[1].
+
+--no-show-forced-updates::
+	By default, git checks if a branch is force-updated during
+	fetch. Pass --no-show-forced-updates or set fetch.showForcedUpdates
+	to false to skip this check for performance reasons. If used during
+	'git-pull' the --ff-only option will still check for forced updates
+	before attempting a fast-forward update. See linkgit:git-config[1].
+
 -4::
 --ipv4::
 	Use IPv4 addresses only, ignoring IPv6 addresses.
diff --git a/builtin/fetch.c b/builtin/fetch.c
index 4ba63d5..571c255 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -39,6 +39,7 @@ enum {
 };
 
 static int fetch_prune_config = -1; /* unspecified */
+static int fetch_show_forced_updates = 1;
 static int prune = -1; /* unspecified */
 #define PRUNE_BY_DEFAULT 0 /* do we prune by default? */
 
@@ -79,6 +80,11 @@ static int git_fetch_config(const char *k, const char *v, void *cb)
 		return 0;
 	}
 
+	if (!strcmp(k, "fetch.showforcedupdates")) {
+		fetch_show_forced_updates = git_config_bool(k, v);
+		return 0;
+	}
+
 	if (!strcmp(k, "submodule.recurse")) {
 		int r = git_config_bool(k, v) ?
 			RECURSE_SUBMODULES_ON : RECURSE_SUBMODULES_OFF;
@@ -169,6 +175,8 @@ static struct option builtin_fetch_options[] = {
 	OPT_STRING_LIST(0, "negotiation-tip", &negotiation_tip, N_("revision"),
 			N_("report that we have only objects reachable from this object")),
 	OPT_PARSE_LIST_OBJECTS_FILTER(&filter_options),
+	OPT_BOOL(0, "show-forced-updates", &fetch_show_forced_updates,
+		 N_("check for forced-updates on all updated branches")),
 	OPT_END()
 };
 
@@ -773,9 +781,10 @@ static int update_local_ref(struct ref *ref,
 		return r;
 	}
 
-	if (in_merge_bases(current, updated)) {
+	if (!fetch_show_forced_updates || in_merge_bases(current, updated)) {
 		struct strbuf quickref = STRBUF_INIT;
 		int r;
+
 		strbuf_add_unique_abbrev(&quickref, &current->object.oid, DEFAULT_ABBREV);
 		strbuf_addstr(&quickref, "..");
 		strbuf_add_unique_abbrev(&quickref, &ref->new_oid, DEFAULT_ABBREV);
diff --git a/t/t5510-fetch.sh b/t/t5510-fetch.sh
index e98d90d..139f710 100755
--- a/t/t5510-fetch.sh
+++ b/t/t5510-fetch.sh
@@ -978,4 +978,27 @@ test_expect_success '--negotiation-tip limits "have" lines sent with HTTP protoc
 	check_negotiation_tip
 '
 
+test_expect_success '--no-show-forced-updates' '
+	mkdir forced-updates &&
+	(
+		cd forced-updates &&
+		git init &&
+		test_commit 1 &&
+		test_commit 2
+	) &&
+	git clone forced-updates forced-update-clone &&
+	git clone forced-updates no-forced-update-clone &&
+	git -C forced-updates reset --hard HEAD~1 &&
+	(
+		cd forced-update-clone &&
+		git fetch --show-forced-updates origin 2>output &&
+		test_i18ngrep "(forced update)" output
+	) &&
+	(
+		cd no-forced-update-clone &&
+		git fetch --no-show-forced-updates origin 2>output &&
+		! test_i18ngrep "(forced update)" output
+	)
+'
+
 test_done
-- 
cgit v0.10.2-6-g49f6


From 377444b440eab3b6ef636df092f7f8299acf75bb Mon Sep 17 00:00:00 2001
From: Derrick Stolee <dstolee@microsoft.com>
Date: Tue, 18 Jun 2019 13:25:27 -0700
Subject: fetch: warn about forced updates in branch listing

The --[no-]show-forced-updates option in 'git fetch' can be confusing
for some users, especially if it is enabled via config setting and not
by argument. Add advice to warn the user that the (forced update)
messages were not listed.

Additionally, warn users when the forced update check takes longer
than ten seconds, and recommend that they disable the check. These
messages can be disabled by the advice.fetchShowForcedUpdates config
setting.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/config/advice.txt b/Documentation/config/advice.txt
index ec4f6ae..1f1e847 100644
--- a/Documentation/config/advice.txt
+++ b/Documentation/config/advice.txt
@@ -4,6 +4,10 @@ advice.*::
 	can tell Git that you do not need help by setting these to 'false':
 +
 --
+	fetchShowForcedUpdates::
+		Advice shown when linkgit:git-fetch[1] takes a long time
+		to calculate forced updates after ref updates, or to warn
+		that the check is disabled.
 	pushUpdateRejected::
 		Set this variable to 'false' if you want to disable
 		'pushNonFFCurrent',
diff --git a/advice.c b/advice.c
index ce5f374..4b283be 100644
--- a/advice.c
+++ b/advice.c
@@ -3,6 +3,7 @@
 #include "color.h"
 #include "help.h"
 
+int advice_fetch_show_forced_updates = 1;
 int advice_push_update_rejected = 1;
 int advice_push_non_ff_current = 1;
 int advice_push_non_ff_matching = 1;
@@ -59,6 +60,7 @@ static struct {
 	const char *name;
 	int *preference;
 } advice_config[] = {
+	{ "fetchShowForcedUpdates", &advice_fetch_show_forced_updates },
 	{ "pushUpdateRejected", &advice_push_update_rejected },
 	{ "pushNonFFCurrent", &advice_push_non_ff_current },
 	{ "pushNonFFMatching", &advice_push_non_ff_matching },
diff --git a/advice.h b/advice.h
index e50f02c..495e532 100644
--- a/advice.h
+++ b/advice.h
@@ -3,6 +3,7 @@
 
 #include "git-compat-util.h"
 
+extern int advice_fetch_show_forced_updates;
 extern int advice_push_update_rejected;
 extern int advice_push_non_ff_current;
 extern int advice_push_non_ff_matching;
diff --git a/builtin/fetch.c b/builtin/fetch.c
index 571c255..cf7eb0d 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -24,6 +24,8 @@
 #include "list-objects-filter-options.h"
 #include "commit-reach.h"
 
+#define FORCED_UPDATES_DELAY_WARNING_IN_MS (10 * 1000)
+
 static const char * const builtin_fetch_usage[] = {
 	N_("git fetch [<options>] [<repository> [<refspec>...]]"),
 	N_("git fetch [<options>] <group>"),
@@ -40,6 +42,7 @@ enum {
 
 static int fetch_prune_config = -1; /* unspecified */
 static int fetch_show_forced_updates = 1;
+static uint64_t forced_updates_ms = 0;
 static int prune = -1; /* unspecified */
 #define PRUNE_BY_DEFAULT 0 /* do we prune by default? */
 
@@ -707,6 +710,7 @@ static int update_local_ref(struct ref *ref,
 	enum object_type type;
 	struct branch *current_branch = branch_get(NULL);
 	const char *pretty_ref = prettify_refname(ref->name);
+	int fast_forward = 0;
 
 	type = oid_object_info(the_repository, &ref->new_oid, NULL);
 	if (type < 0)
@@ -781,7 +785,15 @@ static int update_local_ref(struct ref *ref,
 		return r;
 	}
 
-	if (!fetch_show_forced_updates || in_merge_bases(current, updated)) {
+	if (fetch_show_forced_updates) {
+		uint64_t t_before = getnanotime();
+		fast_forward = in_merge_bases(current, updated);
+		forced_updates_ms += (getnanotime() - t_before) / 1000000;
+	} else {
+		fast_forward = 1;
+	}
+
+	if (fast_forward) {
 		struct strbuf quickref = STRBUF_INIT;
 		int r;
 
@@ -980,6 +992,17 @@ static int store_updated_refs(const char *raw_url, const char *remote_name,
 		      " 'git remote prune %s' to remove any old, conflicting "
 		      "branches"), remote_name);
 
+	if (advice_fetch_show_forced_updates) {
+		if (!fetch_show_forced_updates) {
+			warning(_("Fetch normally indicates which branches had a forced update, but that check has been disabled."));
+			warning(_("To re-enable, use '--show-forced-updates' flag or run 'git config fetch.showForcedUpdates true'."));
+		} else if (forced_updates_ms > FORCED_UPDATES_DELAY_WARNING_IN_MS) {
+			warning(_("It took %.2f seconds to check forced updates. You can use '--no-show-forced-updates'\n"),
+				forced_updates_ms / 1000.0);
+			warning(_("or run 'git config fetch.showForcedUpdates false' to avoid this check.\n"));
+		}
+	}
+
  abort:
 	strbuf_release(&note);
 	free(url);
-- 
cgit v0.10.2-6-g49f6


From 3883c55138dcfbe2d9a24e3f93a2a4b1d376dde6 Mon Sep 17 00:00:00 2001
From: Derrick Stolee <dstolee@microsoft.com>
Date: Tue, 18 Jun 2019 13:25:28 -0700
Subject: pull: add --[no-]show-forced-updates passthrough

The 'git fetch' command can avoid calculating forced updates, so
allow users of 'git pull' to provide that option. This is particularly
necessary when the advice to use '--no-show-forced-updates' is given
at the end of the command.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/pull.c b/builtin/pull.c
index 9dd32a1..f1eaf6e 100644
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -128,6 +128,7 @@ static char *opt_update_shallow;
 static char *opt_refmap;
 static char *opt_ipv4;
 static char *opt_ipv6;
+static int opt_show_forced_updates = -1;
 
 static struct option pull_options[] = {
 	/* Shared options */
@@ -240,6 +241,8 @@ static struct option pull_options[] = {
 	OPT_PASSTHRU('6',  "ipv6", &opt_ipv6, NULL,
 		N_("use IPv6 addresses only"),
 		PARSE_OPT_NOARG),
+	OPT_BOOL(0, "show-forced-updates", &opt_show_forced_updates,
+		 N_("check for forced-updates on all updated branches")),
 
 	OPT_END()
 };
@@ -549,6 +552,10 @@ static int run_fetch(const char *repo, const char **refspecs)
 		argv_array_push(&args, opt_ipv4);
 	if (opt_ipv6)
 		argv_array_push(&args, opt_ipv6);
+	if (opt_show_forced_updates > 0)
+		argv_array_push(&args, "--show-forced-updates");
+	else if (opt_show_forced_updates == 0)
+		argv_array_push(&args, "--no-show-forced-updates");
 
 	if (repo) {
 		argv_array_push(&args, repo);
-- 
cgit v0.10.2-6-g49f6