+/*
+ * Unlike prefix_path, this should be used if the named file does
+ * not have to interact with index entry; i.e. name of a random file
+ * on the filesystem.
+ */
+const char *prefix_filename(const char *pfx, int pfx_len, const char *arg)
+{
+ static char path[PATH_MAX];
+ if (!pfx || !*pfx || arg[0] == '/')
+ return arg;
+ memcpy(path, pfx, pfx_len);
+ strcpy(path + pfx_len, arg);
+ return path;
+}
+
+/*
+ * Verify a filename that we got as an argument for a pathspec
+ * entry. Note that a filename that begins with "-" never verifies
+ * as true, because even if such a filename were to exist, we want
+ * it to be preceded by the "--" marker (or we want the user to
+ * use a format like "./-filename")
+ */
+void verify_filename(const char *prefix, const char *arg)
+{
+ const char *name;
+ struct stat st;
+
+ if (*arg == '-')
+ die("bad flag '%s' used after filename", arg);
+ name = prefix ? prefix_filename(prefix, strlen(prefix), arg) : arg;
+ if (!lstat(name, &st))
+ return;
+ if (errno == ENOENT)
+ die("ambiguous argument '%s': unknown revision or path not in the working tree.\n"
+ "Use '--' to separate paths from revisions", arg);
+ die("'%s': %s", arg, strerror(errno));
+}
+
+/*
+ * Opposite of the above: the command line did not have -- marker
+ * and we parsed the arg as a refname. It should not be interpretable
+ * as a filename.
+ */
+void verify_non_filename(const char *prefix, const char *arg)