fetch: warn about forced updates in branch listing

diff --git a/builtin/fetch.c b/builtin/fetch.c
index 571c2552181d485f73731538712508fc119dbbd0..cf7eb0dd8d48456e5ebfb61b9ebe7c5ff43fd470 100644 (file)
--- 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);