1 files changed, 113 insertions, 2 deletions

diff --git a/config.c b/config.c
index 97ffef4270..18b4219709 100644
--- a/config.c
+++ b/config.c
@@ -11,6 +11,7 @@
 #include "date.h"
 #include "branch.h"
 #include "config.h"
+#include "dir.h"
 #include "parse.h"
 #include "convert.h"
 #include "environment.h"
@@ -1951,10 +1952,110 @@ int git_configset_get_pathname(struct config_set *set, const char *key, char **d
 		return 1;
 }
 
+struct comment_char_config {
+	unsigned last_key_id;
+	bool auto_set;
+};
+
+#define COMMENT_CHAR_CFG_INIT { 0 }
+
+static const char *comment_key_name(unsigned id)
+{
+	static const char *name[] = {
+		"core.commentChar",
+		"core.commentString",
+	};
+
+	if (id >= ARRAY_SIZE(name))
+		BUG("invalid comment key id");
+
+	return name[id];
+}
+
+static void comment_char_callback(const char *key, const char *value,
+				  const struct config_context *ctx UNUSED,
+				  void *data)
+{
+	struct comment_char_config *config = data;
+	unsigned key_id;
+
+	if (!strcmp(key, "core.commentchar"))
+		key_id = 0;
+	else if (!strcmp(key, "core.commentstring"))
+		key_id = 1;
+	else
+		return;
+
+	config->last_key_id = key_id;
+	config->auto_set = value && !strcmp(value, "auto");
+}
+
+struct repo_config {
+	struct repository *repo;
+	struct comment_char_config comment_char_config;
+};
+
+#define REPO_CONFIG_INIT(repo_) {				\
+		.comment_char_config = COMMENT_CHAR_CFG_INIT,	\
+		.repo = repo_,					\
+	};
+
+#ifdef WITH_BREAKING_CHANGES
+static void check_auto_comment_char_config(struct comment_char_config *config)
+{
+	if (!config->auto_set)
+		return;
+
+	die_message(_("Support for '%s=auto' has been removed in Git 3.0"),
+		    comment_key_name(config->last_key_id));
+	die(NULL);
+}
+#else
+static void check_auto_comment_char_config(struct comment_char_config *config)
+{
+	extern bool warn_on_auto_comment_char;
+	const char *DEPRECATED_CONFIG_ENV =
+				"GIT_AUTO_COMMENT_CHAR_CONFIG_WARNING_GIVEN";
+
+	if (!config->auto_set || !warn_on_auto_comment_char)
+		return;
+
+	/*
+	 * Use an environment variable to ensure that subprocesses do not repeat
+	 * the warning.
+	 */
+	if (git_env_bool(DEPRECATED_CONFIG_ENV, false))
+		return;
+
+	setenv(DEPRECATED_CONFIG_ENV, "true", true);
+
+	warning(_("Support for '%s=auto' is deprecated and will be removed in "
+		  "Git 3.0"), comment_key_name(config->last_key_id));
+}
+#endif /* WITH_BREAKING_CHANGES */
+
+static void check_deprecated_config(struct repo_config *config)
+{
+	if (!config->repo->check_deprecated_config)
+			return;
+
+	check_auto_comment_char_config(&config->comment_char_config);
+}
+
+static int repo_config_callback(const char *key, const char *value,
+				const struct config_context *ctx, void *data)
+{
+	struct repo_config *config = data;
+
+	comment_char_callback(key, value, ctx, &config->comment_char_config);
+	return config_set_callback(key, value, ctx, config->repo->config);
+}
+
 /* Functions use to read configuration from a repository */
 static void repo_read_config(struct repository *repo)
 {
 	struct config_options opts = { 0 };
+	struct repo_config config = REPO_CONFIG_INIT(repo);
 
 	opts.respect_includes = 1;
 	opts.commondir = repo->commondir;
@@ -1966,8 +2067,8 @@ static void repo_read_config(struct repository *repo)
 		git_configset_clear(repo->config);
 
 	git_configset_init(repo->config);
-	if (config_with_options(config_set_callback, repo->config, NULL,
-				repo, &opts) < 0)
+	if (config_with_options(repo_config_callback, &config, NULL, repo,
+				&opts) < 0)
 		/*
 		 * config_with_options() normally returns only
 		 * zero, as most errors are fatal, and
@@ -1980,6 +2081,7 @@ static void repo_read_config(struct repository *repo)
 		 * immediately.
 		 */
 		die(_("unknown error occurred while reading the configuration files"));
+	check_deprecated_config(&config);
 }
 
 static void git_config_check_init(struct repository *repo)
@@ -2667,6 +2769,14 @@ int repo_config_set_multivar_in_file_gently(struct repository *r,
 	char *contents = NULL;
 	size_t contents_sz;
 	struct config_store_data store = CONFIG_STORE_INIT;
+	bool saved_check_deprecated_config = r->check_deprecated_config;
+
+	/*
+	 * Do not warn or die if there are deprecated config settings as
+	 * we want the user to be able to change those settings by running
+	 * "git config".
+	 */
+	r->check_deprecated_config = false;
 
 	validate_comment_string(comment);
 
@@ -2898,6 +3008,7 @@ out_free:
 	if (in_fd >= 0)
 		close(in_fd);
 	config_store_data_clear(&store);
+	r->check_deprecated_config = saved_check_deprecated_config;
 	return ret;
 
 write_err_out: