config: use git_config_string() for core.checkRoundTripEncoding

Since this code path was recently converted to check for a NULL value,
it now behaves exactly like git_config_string(). We can shorten the code
a bit by using that helper.

Note that git_config_string() takes a const pointer, but our storage
variable is non-const. We're better off making this "const", though,
since the default value points to a string literal (and thus it would be
an error if anybody tried to write to it).

Signed-off-by: Jeff King <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: peff

config.c

@@ -1551,12 +1551,8 @@ static int git_default_core_config(const char *var, const char *value,
 		return 0;
 	}
 
-	if (!strcmp(var, "core.checkroundtripencoding")) {
-		if (!value)
-			return config_error_nonbool(var);
-		check_roundtrip_encoding = xstrdup(value);
-		return 0;
-	}
+	if (!strcmp(var, "core.checkroundtripencoding"))
+		return git_config_string(&check_roundtrip_encoding, var, value);
 
 	if (!strcmp(var, "core.notesref")) {
 		if (!value)

convert.h

@@ -92,7 +92,7 @@ void convert_attrs(struct index_state *istate,
 		   struct conv_attrs *ca, const char *path);
 
 extern enum eol core_eol;
-extern char *check_roundtrip_encoding;
+extern const char *check_roundtrip_encoding;
 const char *get_cached_convert_stats_ascii(struct index_state *istate,
 					   const char *path);
 const char *get_wt_convert_stats_ascii(const char *path);

environment.c

@@ -64,7 +64,7 @@ const char *excludes_file;
 enum auto_crlf auto_crlf = AUTO_CRLF_FALSE;
 enum eol core_eol = EOL_UNSET;
 int global_conv_flags_eol = CONV_EOL_RNDTRP_WARN;
-char *check_roundtrip_encoding = "SHIFT-JIS";
+const char *check_roundtrip_encoding = "SHIFT-JIS";
 enum branch_track git_branch_track = BRANCH_TRACK_REMOTE;
 enum rebase_setup_type autorebase = AUTOREBASE_NEVER;
 enum push_default_type push_default = PUSH_DEFAULT_UNSPECIFIED;