Re: [PATCH] teach fast-export an --anonymize option

Jeff King [off-list ref] writes:

+/*
+ * We anonymize each component of a path individually,
+ * so that paths a/b and a/c will share a common root.
+ * The paths are cached via anonymize_mem so that repeated
+ * lookups for "a" will yield the same value.
+ */
+static void anonymize_path(struct strbuf *out, const char *path,
+			   struct hashmap *map,
+			   char *(*generate)(const char *, size_t *))
+{
+	while (*path) {
+		const char *end_of_component = strchrnul(path, '/');
+		size_t len = end_of_component - path;
+		const char *c = anonymize_mem(map, generate, path, &len);
+		strbuf_add(out, c, len);
+		path = end_of_component;
+		if (*path)
+			strbuf_addch(out, *path++);
+	}
+}

Do two paths sort the same way before and after anonymisation?  For
example, if generate() works as a simple substitution, it should map
a character that sorts before (or after) '/' with another that also
sorts before (or after) '/' for us to be able to diagnose an error
that comes from D/F sort order confusion.