pathspec: factor out magic-to-name function

When we have unsupported magic in a pathspec (because a command or code
path does not support particular items), we list the unsupported ones in
an error message.

Let's factor out the code here that converts the bits back into their
human-readable names, so that it can be used from other callers, which
may want to provide more flexible error messages.

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

Author: peff

pathspec.c

@@ -525,24 +525,29 @@ static int pathspec_item_cmp(const void *a_, const void *b_)
 	return strcmp(a->match, b->match);
 }
 
-static void NORETURN unsupported_magic(const char *pattern,
-				       unsigned magic)
+void pathspec_magic_names(unsigned magic, struct strbuf *out)
 {
-	struct strbuf sb = STRBUF_INIT;
 	int i;
 	for (i = 0; i < ARRAY_SIZE(pathspec_magic); i++) {
 		const struct pathspec_magic *m = pathspec_magic + i;
 		if (!(magic & m->bit))
 			continue;
-		if (sb.len)
-			strbuf_addstr(&sb, ", ");
+		if (out->len)
+			strbuf_addstr(out, ", ");
 
 		if (m->mnemonic)
-			strbuf_addf(&sb, _("'%s' (mnemonic: '%c')"),
+			strbuf_addf(out, _("'%s' (mnemonic: '%c')"),
 				    m->name, m->mnemonic);
 		else
-			strbuf_addf(&sb, "'%s'", m->name);
+			strbuf_addf(out, "'%s'", m->name);
 	}
+}
+
+static void NORETURN unsupported_magic(const char *pattern,
+				       unsigned magic)
+{
+	struct strbuf sb = STRBUF_INIT;
+	pathspec_magic_names(magic, &sb);
 	/*
 	 * We may want to substitute "this command" with a command
 	 * name. E.g. when "git add -p" or "git add -i" dies when running

pathspec.h

@@ -130,6 +130,14 @@ void parse_pathspec_file(struct pathspec *pathspec,
 void copy_pathspec(struct pathspec *dst, const struct pathspec *src);
 void clear_pathspec(struct pathspec *);
 
+/*
+ * Add a human-readable string to "out" representing the PATHSPEC_* flags set
+ * in "magic". The result is suitable for error messages, but not for
+ * parsing as pathspec magic itself (you get 'icase' with quotes, not
+ * :(icase)).
+ */
+void pathspec_magic_names(unsigned magic, struct strbuf *out);
+
 static inline int ps_strncmp(const struct pathspec_item *item,
 			     const char *s1, const char *s2, size_t n)
 {