reset: remove 'reset.refresh' config option

Remove the 'reset.refresh' option, requiring that users explicitly specify
'--no-refresh' if they want to skip refreshing the index.

The 'reset.refresh' option was introduced in 101cee42dd (reset: introduce
--[no-]refresh option to --mixed, 2022-03-11) as a replacement for the
refresh-skipping behavior originally controlled by 'reset.quiet'.

Although 'reset.refresh=false' functionally served the same purpose as
'reset.quiet=true', it exposed [1] the fact that the existence of a global
"skip refresh" option could potentially cause problems for users. Allowing a
global config option to avoid refreshing the index forces scripts using 'git
reset --mixed' to defensively use '--refresh' if index refresh is expected;
if that option is missing, behavior of a script could vary from user-to-user
without explanation.

Furthermore, globally disabling index refresh in 'reset --mixed' was
initially devised as a passive performance improvement; since the
introduction of the option, other changes have been made to Git (e.g., the
sparse index) with a greater potential performance impact without
sacrificing index correctness. Therefore, we can more aggressively err on
the side of correctness and limit the cases of skipping index refresh to
only when a user specifies the '--no-refresh' option.

[1] https://lore.kernel.org/git/xmqqy2179o3c.fsf@gitster.g/

Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-reset.txt

@@ -109,9 +109,7 @@ OPTIONS
 
 --refresh::
 --no-refresh::
-	Proactively refresh the index after a mixed reset. If unspecified, the
-	behavior falls back on the `reset.refresh` config option. If neither
-	`--[no-]refresh` nor `reset.refresh` are set, refresh is enabled.
+	Refresh the index after a mixed reset. Enabled by default.
 
 --pathspec-from-file=<file>::
 	Pathspec is passed in `<file>` instead of commandline args. If

builtin/reset.c

@@ -423,7 +423,6 @@ int cmd_reset(int argc, const char **argv, const char *prefix)
 	};
 
 	git_config(git_reset_config, NULL);
-	git_config_get_bool("reset.refresh", &refresh);
 
 	argc = parse_options(argc, argv, prefix, options, git_reset_usage,
 						PARSE_OPT_KEEP_DASHDASH);
@@ -529,8 +528,7 @@ int cmd_reset(int argc, const char **argv, const char *prefix)
 				t_delta_in_ms = (getnanotime() - t_begin) / 1000000;
 				if (!quiet && advice_enabled(ADVICE_RESET_NO_REFRESH_WARNING) && t_delta_in_ms > REFRESH_INDEX_DELAY_WARNING_IN_MS) {
 					advise(_("It took %.2f seconds to refresh the index after reset.  You can use\n"
-						 "'--no-refresh' to avoid this.  Set the config setting reset.refresh to false\n"
-						 "to make this the default."), t_delta_in_ms / 1000.0);
+						 "'--no-refresh' to avoid this."), t_delta_in_ms / 1000.0);
 				}
 			}
 		} else {

t/t7102-reset.sh

@@ -493,19 +493,9 @@ test_expect_success '--mixed refreshes the index' '
 '
 
 test_expect_success '--mixed --[no-]refresh sets refresh behavior' '
-	# Verify that --[no-]refresh and `reset.refresh` control index refresh
-
-	# Config setting
-	test_reset_refreshes_index "-c reset.refresh=true" &&
-	! test_reset_refreshes_index "-c reset.refresh=false" &&
-
-	# Command line option
+	# Verify that --[no-]refresh controls index refresh
 	test_reset_refreshes_index "" --refresh &&
-	! test_reset_refreshes_index "" --no-refresh &&
-
-	# Command line option overrides config setting
-	test_reset_refreshes_index "-c reset.refresh=false" --refresh &&
-	! test_reset_refreshes_index "-c reset.refresh=true" --no-refresh
+	! test_reset_refreshes_index "" --no-refresh
 '
 
 test_expect_success '--mixed preserves skip-worktree' '