log: flip the --mailmap default unconditionally

It turns out that being cautious to warn against upcoming default
change was an unpopular behaviour, and such a care can easily be
defeated by distro packagers to render it ineffective anyway.

Just flip the default, with only a mention in the release notes.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/Documentation/RelNotes/2.23.0.txt b/Documentation/RelNotes/2.23.0.txt
index 19e894a..6ef8f21 100644
--- a/Documentation/RelNotes/2.23.0.txt
+++ b/Documentation/RelNotes/2.23.0.txt
@@ -10,6 +10,9 @@
    prerequisite patches in an unstable way, which has been updated to
    compute in a way that is compatible with "git patch-id --stable".
 
+ * The "git log" command by default behaves as if the --mailmap option
+   was given.
+
 
 UI, Workflows & Features
 
@@ -91,11 +94,6 @@
    commit-graph files now, which allows the commit-graph files to be
    updated incrementally.
 
- * The "git log" command learns to issue a warning when log.mailmap
-   configuration is not set and --[no-]mailmap option is not used, to
-   prepare users for future versions of Git that uses the mailmap by
-   default.
-
  * "git range-diff" output has been tweaked for easier identification
    of which part of what file the patch shown is about.
 
diff --git a/builtin/log.c b/builtin/log.c
index 1cf9e37..40b4cbf 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -156,16 +156,6 @@
 		parse_date_format(default_date_mode, &rev->date_mode);
 }
 
-static char warn_unspecified_mailmap_msg[] =
-N_("log.mailmap is not set; its implicit value will change in an\n"
-   "upcoming release. To squelch this message and preserve current\n"
-   "behaviour, set the log.mailmap configuration value to false.\n"
-   "\n"
-   "To squelch this message and adopt the new behaviour now, set the\n"
-   "log.mailmap configuration value to true.\n"
-   "\n"
-   "See 'git help config' and search for 'log.mailmap' for further information.");
-
 static void cmd_log_init_finish(int argc, const char **argv, const char *prefix,
 			 struct rev_info *rev, struct setup_revision_opt *opt)
 {
@@ -214,12 +204,8 @@
 	memset(&w, 0, sizeof(w));
 	userformat_find_requirements(NULL, &w);
 
-	if (mailmap < 0) {
-		if (session_is_interactive() && !rev->pretty_given)
-			warning("%s\n", _(warn_unspecified_mailmap_msg));
-
+	if (mailmap < 0)
 		mailmap = 0;
-	}
 
 	if (!rev->show_notes_given && (!rev->pretty_given || w.notes))
 		rev->show_notes = 1;
diff --git a/t/t7006-pager.sh b/t/t7006-pager.sh
index 7976fa7..00e09a3 100755
--- a/t/t7006-pager.sh
+++ b/t/t7006-pager.sh
@@ -7,8 +7,6 @@
 . "$TEST_DIRECTORY"/lib-terminal.sh
 
 test_expect_success 'setup' '
-	: squelch advice messages during the transition &&
-	git config --global log.mailmap false &&
 	sane_unset GIT_PAGER GIT_PAGER_IN_USE &&
 	test_unconfig core.pager &&