signature: add git_signature_default_from_env

People who are doing a commit expect a unified timestamp between
author and committer information when we're using the current timestamp.
Provide a single function that returns both author and committer
information so that they can have an identical timestamp when none is
specified in the environment.

examples/commit.c

@@ -63,10 +63,8 @@ int lg2_commit(git_repository *repo, int argc, char **argv)
 
 	check_lg2(git_tree_lookup(&tree, repo, &tree_oid), "Error looking up tree", NULL);
 
-	check_lg2(git_signature_default_author(&author_signature, repo),
-			"Error creating author signature", NULL);
-	check_lg2(git_signature_default_committer(&committer_signature, repo),
-			"Error creating committer signature", NULL);
+	check_lg2(git_signature_default_from_env(&author_signature, &committer_signature, repo),
+			"Error creating signature", NULL);
 
 	check_lg2(git_commit_create_v(
 		&commit_oid,

examples/init.c

@@ -130,8 +130,7 @@ static void create_initial_commit(git_repository *repo)
 
 	/** First use the config to initialize a commit signature for the user. */
 
-	if ((git_signature_default_author(&author_sig, repo) < 0) ||
-			(git_signature_default_committer(&committer_sig, repo) < 0))
+	if ((git_signature_default_from_env(&author_sig, &committer_sig, repo) < 0))
 		fatal("Unable to create a commit signature.",
 		      "Perhaps 'user.name' and 'user.email' are not set");
 

examples/stash.c

@@ -108,7 +108,7 @@ static int cmd_push(git_repository *repo, struct opts *opts)
 	if (opts->argc)
 		usage("push does not accept any parameters");
 
-	check_lg2(git_signature_default_author(&signature, repo),
+	check_lg2(git_signature_default_from_env(&signature, NULL, repo),
 		  "Unable to get signature", NULL);
 	check_lg2(git_stash_save(&stashid, repo, signature, NULL, GIT_STASH_DEFAULT),
 		  "Unable to save stash", NULL);

examples/tag.c

@@ -226,7 +226,7 @@ static void action_create_tag(tag_state *state)
 	check_lg2(git_revparse_single(&target, repo, opts->target),
 			"Unable to resolve spec", opts->target);
 
-	check_lg2(git_signature_default_author(&tagger, repo),
+	check_lg2(git_signature_default_from_env(&tagger, NULL, repo),
 			"Unable to create signature", NULL);
 
 	check_lg2(git_tag_create(&oid, repo, opts->tag_name,

include/git2/signature.h

@@ -49,65 +49,53 @@ GIT_EXTERN(int) git_signature_new(git_signature **out, const char *name, const c
 GIT_EXTERN(int) git_signature_now(git_signature **out, const char *name, const char *email);
 
 /**
- * Create a new author action signature with default information based on the
- * configuration and environment variables.
+ * Create a new author and/or committer signatures with default
+ * information based on the configuration and environment variables.
  *
- * If GIT_AUTHOR_NAME environment variable is set it uses that over the
- * user.name value from the configuration.
+ * If `author_out` is set, it will be populated with the author
+ * information. The `GIT_AUTHOR_NAME` and `GIT_AUTHOR_EMAIL`
+ * environment variables will be honored, and `user.name` and
+ * `user.email` configuration options will be honored if the
+ * environment variables are unset. For timestamps, `GIT_AUTHOR_DATE`
+ * will be used, otherwise the current time will be used.
  *
- * If GIT_AUTHOR_EMAIL environment variable is set it uses that over the
- * user.email value from the configuration.  The EMAIL environment variable is
- * the fallback email address in case the user.email configuration value isn't
- * set.
+ * If `committer_out` is set, it will be populated with the
+ * committer information. The `GIT_COMMITTER_NAME` and
+ * `GIT_COMMITTER_EMAIL` environment variables will be honored,
+ * and `user.name` and `user.email` configuration options will
+ * be honored if the environment variables are unset. For timestamps,
+ * `GIT_COMMITTER_DATE` will be used, otherwise the current time will
+ * be used.
  *
- * If GIT_AUTHOR_DATE is set it uses that, otherwise it uses the current time
- * as the timestamp.
+ * If neither `GIT_AUTHOR_DATE` nor `GIT_COMMITTER_DATE` are set,
+ * both timestamps will be set to the same time.
  *
- * It will return GIT_ENOTFOUND if either the user.name or user.email are not
- * set and there is no fallback from an environment variable.
+ * It will return `GIT_ENOTFOUND` if either the `user.name` or
+ * `user.email` are not set and there is no fallback from an environment
+ * variable. One of `author_out` or `committer_out` must be set.
  *
- * @param out new signature
+ * @param author_out pointer to set the author signature, or NULL
+ * @param committer_out pointer to set the committer signature, or NULL
  * @param repo repository pointer
  * @return 0 on success, GIT_ENOTFOUND if config is missing, or error code
  */
-GIT_EXTERN(int) git_signature_default_author(git_signature **out, git_repository *repo);
-
-/**
- * Create a new committer action signature with default information based on
- * the configuration and environment variables.
- *
- * If GIT_COMMITTER_NAME environment variable is set it uses that over the
- * user.name value from the configuration.
- *
- * If GIT_COMMITTER_EMAIL environment variable is set it uses that over the
- * user.email value from the configuration.  The EMAIL environment variable is
- * the fallback email address in case the user.email configuration value isn't
- * set.
- *
- * If GIT_COMMITTER_DATE is set it uses that, otherwise it uses the current
- * time as the timestamp.
- *
- * It will return GIT_ENOTFOUND if either the user.name or user.email are not
- * set and there is no fallback from an environment variable.
- *
- * @param out new signature
- * @param repo repository pointer
- * @return 0 on success, GIT_ENOTFOUND if config is missing, or error code
- */
-GIT_EXTERN(int) git_signature_default_committer(git_signature **out, git_repository *repo);
+GIT_EXTERN(int) git_signature_default_from_env(
+	git_signature **author_out,
+	git_signature **committer_out,
+	git_repository *repo);
 
 /**
  * Create a new action signature with default user and now timestamp.
  *
- * Warning: This function may be deprecated in the future.  Use one of
- * git_signature_default_author or git_signature_default_committer instead.
- * These are more compliant with how git constructs default signatures.
- *
  * This looks up the user.name and user.email from the configuration and
  * uses the current time as the timestamp, and creates a new signature
  * based on that information.  It will return GIT_ENOTFOUND if either the
  * user.name or user.email are not set.
  *
+ * Note that these do not examine environment variables, only the
+ * configuration files. Use `git_signature_default_from_env` to
+ * consider the environment variables.
+ *
  * @param out new signature
  * @param repo repository pointer
  * @return 0 on success, GIT_ENOTFOUND if config is missing, or error code

src/libgit2/signature.c

@@ -153,15 +153,10 @@ int git_signature__pdup(git_signature **dest, const git_signature *source, git_p
 	return 0;
 }
 
-int git_signature_now(git_signature **sig_out, const char *name, const char *email)
+static void current_time(time_t *now_out, int *offset_out)
 {
-	time_t now;
 	time_t offset;
-	struct tm *utc_tm;
-	git_signature *sig;
-	struct tm _utc;
-
-	*sig_out = NULL;
+	struct tm _utc, *utc_tm;
 
 	/*
 	 * Get the current time as seconds since the epoch and
@@ -171,21 +166,28 @@ int git_signature_now(git_signature **sig_out, const char *name, const char *ema
 	 * us that time as seconds since the epoch. The difference
 	 * between its return value and 'now' is our offset to UTC.
 	 */
-	time(&now);
-	utc_tm = p_gmtime_r(&now, &_utc);
+	time(now_out);
+	utc_tm = p_gmtime_r(now_out, &_utc);
 	utc_tm->tm_isdst = -1;
-	offset = (time_t)difftime(now, mktime(utc_tm));
+	offset = (time_t)difftime(*now_out, mktime(utc_tm));
 	offset /= 60;
 
-	if (git_signature_new(&sig, name, email, now, (int)offset) < 0)
-		return -1;
-
-	*sig_out = sig;
-
-	return 0;
+	*offset_out = (int)offset;
+}
+
+int git_signature_now(
+	git_signature **sig_out,
+	const char *name,
+	const char *email)
+{
+	time_t now;
+	int offset;
+
+	current_time(&now, &offset);
+
+	return git_signature_new(sig_out, name, email, now, offset);
 }
 
-#ifndef GIT_DEPRECATE_HARD
 int git_signature_default(git_signature **out, git_repository *repo)
 {
 	int error;
@@ -202,10 +204,15 @@ int git_signature_default(git_signature **out, git_repository *repo)
 	git_config_free(cfg);
 	return error;
 }
-#endif
 
-static int git_signature__default_from_env(const char *name_env_var, const char *email_env_var,
-		const char *date_env_var, git_signature **out, git_repository *repo)
+static int user_from_env(
+	git_signature **out,
+	git_repository *repo,
+	const char *name_env_var,
+	const char *email_env_var,
+	const char *date_env_var,
+	time_t default_time,
+	int default_offset)
 {
 	int error;
 	git_config *cfg;
@@ -215,46 +222,53 @@ static int git_signature__default_from_env(const char *name_env_var, const char
 	git_str name_env = GIT_STR_INIT;
 	git_str email_env = GIT_STR_INIT;
 	git_str date_env = GIT_STR_INIT;
-	int have_email_env = -1;
 
 	if ((error = git_repository_config_snapshot(&cfg, repo)) < 0)
 		return error;
 
 	/* Check if the environment variable for the name is set */
-	if (!(git__getenv(&name_env, name_env_var)))
+	if (!(git__getenv(&name_env, name_env_var))) {
 		name = git_str_cstr(&name_env);
-	else
+	} else {
 		/* or else read the configuration value. */
 		if ((error = git_config_get_string(&name, cfg, "user.name")) < 0)
 			goto done;
+	}
 
 	/* Check if the environment variable for the email is set. */
-	if (!(git__getenv(&email_env, email_env_var)))
+	if (!(git__getenv(&email_env, email_env_var))) {
 		email = git_str_cstr(&email_env);
-	else {
-		/* Check if the fallback EMAIL environment variable is set
-		 * before we check the configuration so that we preserve the
-		 * error message if the configuration value is missing. */
-		git_str_dispose(&email_env);
-		have_email_env = !git__getenv(&email_env, "EMAIL");
-		if ((error = git_config_get_string(&email, cfg, "user.email")) < 0) {
-			if (have_email_env) {
-				email = git_str_cstr(&email_env);
-				error = 0;
-			} else
+	} else {
+		if ((error = git_config_get_string(&email, cfg, "user.email")) == GIT_ENOTFOUND) {
+			git_error *last_error;
+
+			git_error_save(&last_error);
+
+			if ((error = git__getenv(&email_env, "EMAIL")) < 0) {
+				git_error_restore(last_error);
+				error = GIT_ENOTFOUND;
 				goto done;
+			}
+
+			email = git_str_cstr(&email_env);
+			git_error_free(last_error);
+		} else if (error < 0) {
+			goto done;
 		}
 	}
 
 	/* Check if the environment variable for the timestamp is set */
 	if (!(git__getenv(&date_env, date_env_var))) {
 		date = git_str_cstr(&date_env);
+
 		if ((error = git_date_offset_parse(&timestamp, &offset, date)) < 0)
 			goto done;
-		error = git_signature_new(out, name, email, timestamp, offset);
-	} else
-		/* or else default to the current timestamp. */
-		error = git_signature_now(out, name, email);
+	} else {
+		timestamp = default_time;
+		offset = default_offset;
+	}
+
+	error = git_signature_new(out, name, email, timestamp, offset);
 
 done:
 	git_config_free(cfg);
@@ -264,16 +278,45 @@ done:
 	return error;
 }
 
-int git_signature_default_author(git_signature **out, git_repository *repo)
+int git_signature_default_from_env(
+	git_signature **author_out,
+	git_signature **committer_out,
+	git_repository *repo)
 {
-	return git_signature__default_from_env("GIT_AUTHOR_NAME", "GIT_AUTHOR_EMAIL",
-			"GIT_AUTHOR_DATE", out, repo);
-}
+	git_signature *author = NULL, *committer = NULL;
+	time_t now;
+	int offset;
+	int error;
 
-int git_signature_default_committer(git_signature **out, git_repository *repo)
-{
-	return git_signature__default_from_env("GIT_COMMITTER_NAME", "GIT_COMMITTER_EMAIL",
-			"GIT_COMMITTER_DATE", out, repo);
+	GIT_ASSERT_ARG(author_out || committer_out);
+	GIT_ASSERT_ARG(repo);
+
+	current_time(&now, &offset);
+
+	if (author_out &&
+	    (error = user_from_env(&author, repo, "GIT_AUTHOR_NAME",
+			"GIT_AUTHOR_EMAIL", "GIT_AUTHOR_DATE",
+			now, offset)) < 0)
+		goto on_error;
+
+	if (committer_out &&
+	    (error = user_from_env(&committer, repo, "GIT_COMMITTER_NAME",
+			"GIT_COMMITTER_EMAIL", "GIT_COMMITTER_DATE",
+			now, offset)) < 0)
+		goto on_error;
+
+	if (author_out)
+		*author_out = author;
+
+	if (committer_out)
+		*committer_out = committer;
+
+	return 0;
+
+on_error:
+	git__free(author);
+	git__free(committer);
+	return error;
 }
 
 int git_signature__parse(git_signature *sig, const char **buffer_out,

tests/libgit2/commit/signature.c

@@ -167,7 +167,7 @@ void test_commit_signature__cleanup(void)
 	g_repo = NULL;
 }
 
-void test_commit_signature__signature_default(void)
+void test_commit_signature__from_env(void)
 {
 	git_signature *author_sign, *committer_sign;
 	git_config *cfg, *local;
@@ -179,14 +179,12 @@ void test_commit_signature__signature_default(void)
 	cl_setenv("GIT_AUTHOR_EMAIL", NULL);
 	cl_setenv("GIT_COMMITTER_NAME", NULL);
 	cl_setenv("GIT_COMMITTER_EMAIL", NULL);
-	cl_git_fail(git_signature_default_author(&author_sign, g_repo));
-	cl_git_fail(git_signature_default_committer(&committer_sign, g_repo));
+	cl_git_fail(git_signature_default_from_env(&author_sign, &committer_sign, g_repo));
 	/* Name is read from configuration and email is read from fallback EMAIL
 	 * environment variable */
 	cl_git_pass(git_config_set_string(local, "user.name", "Name (config)"));
 	cl_setenv("EMAIL", "email-envvar@example.com");
-	cl_git_pass(git_signature_default_author(&author_sign, g_repo));
-	cl_git_pass(git_signature_default_committer(&committer_sign, g_repo));
+	cl_git_pass(git_signature_default_from_env(&author_sign, &committer_sign, g_repo));
 	cl_assert_equal_s("Name (config)", author_sign->name);
 	cl_assert_equal_s("email-envvar@example.com", author_sign->email);
 	cl_assert_equal_s("Name (config)", committer_sign->name);
@@ -200,8 +198,7 @@ void test_commit_signature__signature_default(void)
 	cl_setenv("GIT_AUTHOR_EMAIL", "author-envvar@example.com");
 	cl_setenv("GIT_COMMITTER_NAME", "Committer (envvar)");
 	cl_setenv("GIT_COMMITTER_EMAIL", "committer-envvar@example.com");
-	cl_git_pass(git_signature_default_author(&author_sign, g_repo));
-	cl_git_pass(git_signature_default_committer(&committer_sign, g_repo));
+	cl_git_pass(git_signature_default_from_env(&author_sign, &committer_sign, g_repo));
 	cl_assert_equal_s("Author (envvar)", author_sign->name);
 	cl_assert_equal_s("author-envvar@example.com", author_sign->email);
 	cl_assert_equal_s("Committer (envvar)", committer_sign->name);
@@ -214,8 +211,7 @@ void test_commit_signature__signature_default(void)
 	cl_setenv("GIT_AUTHOR_EMAIL", NULL);
 	cl_setenv("GIT_COMMITTER_NAME", NULL);
 	cl_setenv("GIT_COMMITTER_EMAIL", NULL);
-	cl_git_pass(git_signature_default_author(&author_sign, g_repo));
-	cl_git_pass(git_signature_default_committer(&committer_sign, g_repo));
+	cl_git_pass(git_signature_default_from_env(&author_sign, &committer_sign, g_repo));
 	cl_assert_equal_s("Name (config)", author_sign->name);
 	cl_assert_equal_s("config@example.com", author_sign->email);
 	cl_assert_equal_s("Name (config)", committer_sign->name);
@@ -225,8 +221,7 @@ void test_commit_signature__signature_default(void)
 	/* We can also override the timestamp with an environment variable */
 	cl_setenv("GIT_AUTHOR_DATE", "1971-02-03 04:05:06+01");
 	cl_setenv("GIT_COMMITTER_DATE", "1988-09-10 11:12:13-01");
-	cl_git_pass(git_signature_default_author(&author_sign, g_repo));
-	cl_git_pass(git_signature_default_committer(&committer_sign, g_repo));
+	cl_git_pass(git_signature_default_from_env(&author_sign, &committer_sign, g_repo));
 	cl_assert_equal_i(34398306, author_sign->when.time);  /* 1971-02-03 03:05:06 UTC */
 	cl_assert_equal_i(60, author_sign->when.offset);
 	cl_assert_equal_i(589896733, committer_sign->when.time);  /* 1988-09-10 12:12:13 UTC */