advice: revamp advise API

Currently it's very easy for the advice library's callers to miss
checking the visibility step before printing an advice. Also, it makes
more sense for this step to be handled by the advice library.

Add a new advise_if_enabled function that checks the visibility of
advice messages before printing.

Add a new helper advise_enabled to check the visibility of the advice
if the caller needs to carry out complicated processing based on that
value.

A list of advice_settings is added to cache the config variables names
and values, it's intended to replace advice_config[] and the global
variables once we migrate all the callers to use the new APIs.

Signed-off-by: Heba Waly <heba.waly@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

7 files changed, 188 insertions, 4 deletions

diff --git a/Makefile b/Makefile
index 09f98b777c..ed923a3e81 100644
--- a/Makefile
+++ b/Makefile
@@ -695,6 +695,7 @@ X =
 
 PROGRAMS += $(patsubst %.o,git-%$X,$(PROGRAM_OBJS))
 
+TEST_BUILTINS_OBJS += test-advise.o
 TEST_BUILTINS_OBJS += test-chmtime.o
 TEST_BUILTINS_OBJS += test-config.o
 TEST_BUILTINS_OBJS += test-ctype.o
diff --git a/advice.c b/advice.c
index 258cc9ba7a..9814d6cdfd 100644
--- a/advice.c
+++ b/advice.c
@@ -96,13 +96,59 @@ static struct {
 	{ "pushNonFastForward", &advice_push_update_rejected }
 };
 
-static void vadvise(const char *advice, va_list params)
+static struct {
+	const char *key;
+	int enabled;
+} advice_setting[] = {
+	[ADVICE_ADD_EMBEDDED_REPO]			= { "addEmbeddedRepo", 1 },
+	[ADVICE_AM_WORK_DIR] 				= { "amWorkDir", 1 },
+	[ADVICE_CHECKOUT_AMBIGUOUS_REMOTE_BRANCH_NAME] 	= { "checkoutAmbiguousRemoteBranchName", 1 },
+	[ADVICE_COMMIT_BEFORE_MERGE]			= { "commitBeforeMerge", 1 },
+	[ADVICE_DETACHED_HEAD]				= { "detachedHead", 1 },
+	[ADVICE_FETCH_SHOW_FORCED_UPDATES]		= { "fetchShowForcedUpdates", 1 },
+	[ADVICE_GRAFT_FILE_DEPRECATED]			= { "graftFileDeprecated", 1 },
+	[ADVICE_IGNORED_HOOK]				= { "ignoredHook", 1 },
+	[ADVICE_IMPLICIT_IDENTITY]			= { "implicitIdentity", 1 },
+	[ADVICE_NESTED_TAG]				= { "nestedTag", 1 },
+	[ADVICE_OBJECT_NAME_WARNING]			= { "objectNameWarning", 1 },
+	[ADVICE_PUSH_ALREADY_EXISTS]			= { "pushAlreadyExists", 1 },
+	[ADVICE_PUSH_FETCH_FIRST]			= { "pushFetchFirst", 1 },
+	[ADVICE_PUSH_NEEDS_FORCE]			= { "pushNeedsForce", 1 },
+
+	/* make this an alias for backward compatibility */
+	[ADVICE_PUSH_UPDATE_REJECTED_ALIAS]		= { "pushNonFastForward", 1 },
+
+	[ADVICE_PUSH_NON_FF_CURRENT]			= { "pushNonFFCurrent", 1 },
+	[ADVICE_PUSH_NON_FF_MATCHING]			= { "pushNonFFMatching", 1 },
+	[ADVICE_PUSH_UNQUALIFIED_REF_NAME]		= { "pushUnqualifiedRefName", 1 },
+	[ADVICE_PUSH_UPDATE_REJECTED]			= { "pushUpdateRejected", 1 },
+	[ADVICE_RESET_QUIET_WARNING]			= { "resetQuiet", 1 },
+	[ADVICE_RESOLVE_CONFLICT]			= { "resolveConflict", 1 },
+	[ADVICE_RM_HINTS]				= { "rmHints", 1 },
+	[ADVICE_SEQUENCER_IN_USE]			= { "sequencerInUse", 1 },
+	[ADVICE_SET_UPSTREAM_FAILURE]			= { "setUpstreamFailure", 1 },
+	[ADVICE_STATUS_AHEAD_BEHIND_WARNING]		= { "statusAheadBehindWarning", 1 },
+	[ADVICE_STATUS_HINTS]				= { "statusHints", 1 },
+	[ADVICE_STATUS_U_OPTION]			= { "statusUoption", 1 },
+	[ADVICE_SUBMODULE_ALTERNATE_ERROR_STRATEGY_DIE] = { "submoduleAlternateErrorStrategyDie", 1 },
+	[ADVICE_WAITING_FOR_EDITOR]			= { "waitingForEditor", 1 },
+};
+
+static const char turn_off_instructions[] =
+N_("\n"
+   "Disable this message with \"git config advice.%s false\"");
+
+static void vadvise(const char *advice, int display_instructions,
+		    const char *key, va_list params)
 {
 	struct strbuf buf = STRBUF_INIT;
 	const char *cp, *np;
 
 	strbuf_vaddf(&buf, advice, params);
 
+	if (display_instructions)
+		strbuf_addf(&buf, turn_off_instructions, key);
+
 	for (cp = buf.buf; *cp; cp = np) {
 		np = strchrnul(cp, '\n');
 		fprintf(stderr,	_("%shint: %.*s%s\n"),
@@ -119,7 +165,30 @@ void advise(const char *advice, ...)
 {
 	va_list params;
 	va_start(params, advice);
-	vadvise(advice, params);
+	vadvise(advice, 0, "", params);
+	va_end(params);
+}
+
+int advice_enabled(enum advice_type type)
+{
+	switch(type) {
+	case ADVICE_PUSH_UPDATE_REJECTED:
+		return advice_setting[ADVICE_PUSH_UPDATE_REJECTED].enabled &&
+		       advice_setting[ADVICE_PUSH_UPDATE_REJECTED_ALIAS].enabled;
+	default:
+		return advice_setting[type].enabled;
+	}
+}
+
+void advise_if_enabled(enum advice_type type, const char *advice, ...)
+{
+	va_list params;
+
+	if (!advice_enabled(type))
+		return;
+
+	va_start(params, advice);
+	vadvise(advice, 1, advice_setting[type].key, params);
 	va_end(params);
 }
 
@@ -149,6 +218,13 @@ int git_default_advice_config(const char *var, const char *value)
 		if (strcasecmp(k, advice_config[i].name))
 			continue;
 		*advice_config[i].preference = git_config_bool(var, value);
+		break;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(advice_setting); i++) {
+		if (strcasecmp(k, advice_setting[i].key))
+			continue;
+		advice_setting[i].enabled = git_config_bool(var, value);
 		return 0;
 	}
 
@@ -159,8 +235,8 @@ void list_config_advices(struct string_list *list, const char *prefix)
 {
 	int i;
 
-	for (i = 0; i < ARRAY_SIZE(advice_config); i++)
-		list_config_item(list, prefix, advice_config[i].name);
+	for (i = 0; i < ARRAY_SIZE(advice_setting); i++)
+		list_config_item(list, prefix, advice_setting[i].key);
 }
 
 int error_resolve_conflict(const char *me)
diff --git a/advice.h b/advice.h
index b706780614..d72ab4a06c 100644
--- a/advice.h
+++ b/advice.h
@@ -32,9 +32,60 @@ extern int advice_checkout_ambiguous_remote_branch_name;
 extern int advice_nested_tag;
 extern int advice_submodule_alternate_error_strategy_die;
 
+/*
+ * To add a new advice, you need to:
+ * Define a new advice_type.
+ * Add a new entry to advice_setting array.
+ * Add the new config variable to Documentation/config/advice.txt.
+ * Call advise_if_enabled to print your advice.
+ */
+ enum advice_type {
+	ADVICE_ADD_EMBEDDED_REPO,
+	ADVICE_AM_WORK_DIR,
+	ADVICE_CHECKOUT_AMBIGUOUS_REMOTE_BRANCH_NAME,
+	ADVICE_COMMIT_BEFORE_MERGE,
+	ADVICE_DETACHED_HEAD,
+	ADVICE_FETCH_SHOW_FORCED_UPDATES,
+	ADVICE_GRAFT_FILE_DEPRECATED,
+	ADVICE_IGNORED_HOOK,
+	ADVICE_IMPLICIT_IDENTITY,
+	ADVICE_NESTED_TAG,
+	ADVICE_OBJECT_NAME_WARNING,
+	ADVICE_PUSH_ALREADY_EXISTS,
+	ADVICE_PUSH_FETCH_FIRST,
+	ADVICE_PUSH_NEEDS_FORCE,
+	ADVICE_PUSH_NON_FF_CURRENT,
+	ADVICE_PUSH_NON_FF_MATCHING,
+	ADVICE_PUSH_UNQUALIFIED_REF_NAME,
+	ADVICE_PUSH_UPDATE_REJECTED_ALIAS,
+	ADVICE_PUSH_UPDATE_REJECTED,
+	ADVICE_RESET_QUIET_WARNING,
+	ADVICE_RESOLVE_CONFLICT,
+	ADVICE_RM_HINTS,
+	ADVICE_SEQUENCER_IN_USE,
+	ADVICE_SET_UPSTREAM_FAILURE,
+	ADVICE_STATUS_AHEAD_BEHIND_WARNING,
+	ADVICE_STATUS_HINTS,
+	ADVICE_STATUS_U_OPTION,
+	ADVICE_SUBMODULE_ALTERNATE_ERROR_STRATEGY_DIE,
+	ADVICE_WAITING_FOR_EDITOR,
+};
+
 int git_default_advice_config(const char *var, const char *value);
 __attribute__((format (printf, 1, 2)))
 void advise(const char *advice, ...);
+
+/**
+ * Checks if advice type is enabled (can be printed to the user).
+ * Should be called before advise().
+ */
+int advice_enabled(enum advice_type type);
+
+/**
+ * Checks the visibility of the advice before printing.
+ */
+void advise_if_enabled(enum advice_type type, const char *advice, ...);
+
 int error_resolve_conflict(const char *me);
 void NORETURN die_resolve_conflict(const char *me);
 void NORETURN die_conclude_merge(void);
diff --git a/t/helper/test-advise.c b/t/helper/test-advise.c
new file mode 100644
index 0000000000..38cdc2884e
--- /dev/null
+++ b/t/helper/test-advise.c
@@ -0,0 +1,22 @@
+#include "test-tool.h"
+#include "cache.h"
+#include "advice.h"
+#include "config.h"
+
+int cmd__advise_if_enabled(int argc, const char **argv)
+{
+	if (!argv[1])
+	die("usage: %s <advice>", argv[0]);
+
+	setup_git_directory();
+	git_config(git_default_config, NULL);
+
+	/*
+	 * Any advice type can be used for testing, but NESTED_TAG was
+	 * selected here and in t0018 where this command is being
+	 * executed.
+	 */
+	advise_if_enabled(ADVICE_NESTED_TAG, argv[1]);
+
+	return 0;
+}
diff --git a/t/helper/test-tool.c b/t/helper/test-tool.c
index f20989d449..6977badc69 100644
--- a/t/helper/test-tool.c
+++ b/t/helper/test-tool.c
@@ -14,6 +14,7 @@ struct test_cmd {
 };
 
 static struct test_cmd cmds[] = {
+	{ "advise", cmd__advise_if_enabled },
 	{ "chmtime", cmd__chmtime },
 	{ "config", cmd__config },
 	{ "ctype", cmd__ctype },
diff --git a/t/helper/test-tool.h b/t/helper/test-tool.h
index 8ed2af71d1..ca5e33b842 100644
--- a/t/helper/test-tool.h
+++ b/t/helper/test-tool.h
@@ -4,6 +4,7 @@
 #define USE_THE_INDEX_COMPATIBILITY_MACROS
 #include "git-compat-util.h"
 
+int cmd__advise_if_enabled(int argc, const char **argv);
 int cmd__chmtime(int argc, const char **argv);
 int cmd__config(int argc, const char **argv);
 int cmd__ctype(int argc, const char **argv);
diff --git a/t/t0018-advice.sh b/t/t0018-advice.sh
new file mode 100755
index 0000000000..e03554d2f3
--- /dev/null
+++ b/t/t0018-advice.sh
@@ -0,0 +1,32 @@
+#!/bin/sh
+
+test_description='Test advise_if_enabled functionality'
+
+. ./test-lib.sh
+
+test_expect_success 'advice should be printed when config variable is unset' '
+	cat >expect <<-\EOF &&
+	hint: This is a piece of advice
+	hint: Disable this message with "git config advice.nestedTag false"
+	EOF
+	test-tool advise "This is a piece of advice" 2>actual &&
+	test_i18ncmp expect actual
+'
+
+test_expect_success 'advice should be printed when config variable is set to true' '
+	cat >expect <<-\EOF &&
+	hint: This is a piece of advice
+	hint: Disable this message with "git config advice.nestedTag false"
+	EOF
+	test_config advice.nestedTag true &&
+	test-tool advise "This is a piece of advice" 2>actual &&
+	test_i18ncmp expect actual
+'
+
+test_expect_success 'advice should not be printed when config variable is set to false' '
+	test_config advice.nestedTag false &&
+	test-tool advise "This is a piece of advice" 2>actual &&
+	test_must_be_empty actual
+'
+
+test_done