advice: allow disabling default branch name advice

The default branch name advice message is displayed when
`repo_default_branch_name()` is invoked and the `init.defaultBranch`
config is not set. In this scenario, the advice message is always shown
even if the `--no-advice` option is used.

Adapt `repo_default_branch_name()` to allow the default branch name
advice message to be disabled with the `--no-advice` option and
corresponding configuration.

Signed-off-by: Justin Tobler <jltobler@gmail.com>
Acked-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: jltobler

advice.c

@@ -51,6 +51,7 @@ static struct {
 	[ADVICE_AM_WORK_DIR] 				= { "amWorkDir" },
 	[ADVICE_CHECKOUT_AMBIGUOUS_REMOTE_BRANCH_NAME] 	= { "checkoutAmbiguousRemoteBranchName" },
 	[ADVICE_COMMIT_BEFORE_MERGE]			= { "commitBeforeMerge" },
+	[ADVICE_DEFAULT_BRANCH_NAME]			= { "defaultBranchName" },
 	[ADVICE_DETACHED_HEAD]				= { "detachedHead" },
 	[ADVICE_DIVERGING]				= { "diverging" },
 	[ADVICE_FETCH_SET_HEAD_WARN]			= { "fetchRemoteHEADWarn" },

advice.h

@@ -18,6 +18,7 @@ enum advice_type {
 	ADVICE_AM_WORK_DIR,
 	ADVICE_CHECKOUT_AMBIGUOUS_REMOTE_BRANCH_NAME,
 	ADVICE_COMMIT_BEFORE_MERGE,
+	ADVICE_DEFAULT_BRANCH_NAME,
 	ADVICE_DETACHED_HEAD,
 	ADVICE_DIVERGING,
 	ADVICE_FETCH_SET_HEAD_WARN,

refs.c

@@ -664,7 +664,8 @@ char *repo_default_branch_name(struct repository *r, int quiet)
 	if (!ret) {
 		ret = xstrdup("master");
 		if (!quiet)
-			advise(_(default_branch_name_advice), ret);
+			advise_if_enabled(ADVICE_DEFAULT_BRANCH_NAME,
+					  _(default_branch_name_advice), ret);
 	}
 
 	full_ref = xstrfmt("refs/heads/%s", ret);

t/t0001-init.sh

@@ -830,6 +830,14 @@ test_expect_success 'advice on unconfigured init.defaultBranch' '
 	test_grep "<YELLOW>hint: " decoded
 '
 
+test_expect_success 'advice on unconfigured init.defaultBranch disabled' '
+	test_when_finished "rm -rf no-advice" &&
+
+	GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME= \
+		git -c advice.defaultBranchName=false init no-advice 2>err &&
+	test_grep ! "hint: " err
+'
+
 test_expect_success 'overridden default main branch name (env)' '
 	test_config_global init.defaultBranch nmb &&
 	GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=env git init main-branch-env &&