ident.c: check explicit identity for name and email separately

bb1ae3f (commit: Show committer if automatic, 2008-05-04) added a logic to
check both name and email were given explicitly by the end user, but it
assumed that fmt_ident() is never called before git_default_user_config()
is called, which was fragile.  The former calls setup_ident() and fills
the "default" name and email, so the check in the config parser would have
mistakenly said both are given even if only user.name was provided.

Make the logic more robust by keeping track of name and email separately.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Acked-by: Santi Béjar <santi@agolina.net>

builtin-commit.c

@@ -624,7 +624,7 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 				author_ident);
 		free(author_ident);
 
-		if (!user_ident_explicitly_given)
+		if (user_ident_explicitly_given != IDENT_ALL_GIVEN)
 			fprintf(fp,
 				"%s"
 				"# Committer: %s\n",

cache.h

@@ -925,6 +925,9 @@ extern const char *config_exclusive_filename;
 #define MAX_GITNAME (1000)
 extern char git_default_email[MAX_GITNAME];
 extern char git_default_name[MAX_GITNAME];
+#define IDENT_NAME_GIVEN 01
+#define IDENT_MAIL_GIVEN 02
+#define IDENT_ALL_GIVEN (IDENT_NAME_GIVEN|IDENT_MAIL_GIVEN)
 extern int user_ident_explicitly_given;
 
 extern const char *git_commit_encoding;

config.c

@@ -528,17 +528,15 @@ static int git_default_user_config(const char *var, const char *value)
 		if (!value)
 			return config_error_nonbool(var);
 		strlcpy(git_default_name, value, sizeof(git_default_name));
-		if (git_default_email[0])
-			user_ident_explicitly_given = 1;
+		user_ident_explicitly_given |= IDENT_NAME_GIVEN;
 		return 0;
 	}
 
 	if (!strcmp(var, "user.email")) {
 		if (!value)
 			return config_error_nonbool(var);
 		strlcpy(git_default_email, value, sizeof(git_default_email));
-		if (git_default_name[0])
-			user_ident_explicitly_given = 1;
+		user_ident_explicitly_given |= IDENT_MAIL_GIVEN;
 		return 0;
 	}
 

ident.c

@@ -249,9 +249,10 @@ const char *git_author_info(int flag)
 
 const char *git_committer_info(int flag)
 {
-	if (getenv("GIT_COMMITTER_NAME") &&
-	    getenv("GIT_COMMITTER_EMAIL"))
-		user_ident_explicitly_given = 1;
+	if (getenv("GIT_COMMITTER_NAME"))
+		user_ident_explicitly_given |= IDENT_NAME_GIVEN;
+	if (getenv("GIT_COMMITTER_EMAIL"))
+		user_ident_explicitly_given |= IDENT_MAIL_GIVEN;
 	return fmt_ident(getenv("GIT_COMMITTER_NAME"),
 			 getenv("GIT_COMMITTER_EMAIL"),
 			 getenv("GIT_COMMITTER_DATE"),