From c05d09044fb71bdea599c81bf0ae896a5503e76a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marco=20Trevisan=20=28Trevi=C3=B1o=29?= <mail@3v1n0.net>
Date: Fri, 15 Jul 2022 01:27:33 +0200
Subject: [PATCH] gregex: Ensure we translate the errcode without asserting on
 G_REGEX_ERROR_COMPILE

Since commit 8d5a44dc in order to ensure that we were setting the errcode in
translate_compile_error(), we did an assert checking whether it was a
valid value, but we assumed that 0 was not a valid error, while it is as
it's the generic G_REGEX_ERROR_COMPILE.

So, set errcode and errmsg to invalid values before translating and
ensure we've change them.

Fixes: #2694
---
 glib/gregex.c      |  8 ++++++--
 glib/tests/regex.c | 13 +++++++++++++
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/glib/gregex.c b/glib/gregex.c
index 5fc7b16bc..2a54929bf 100644
--- a/glib/gregex.c
+++ b/glib/gregex.c
@@ -476,8 +476,12 @@ translate_compile_error (gint *errcode, const gchar **errmsg)
    * Note that there can be more PCRE errors with the same GRegexError
    * and that some PCRE errors are useless for us.
    */
+  gint original_errcode = *errcode;
 
-  switch (*errcode)
+  *errcode = -1;
+  *errmsg = NULL;
+
+  switch (original_errcode)
     {
     case PCRE2_ERROR_END_BACKSLASH:
       *errcode = G_REGEX_ERROR_STRAY_BACKSLASH;
@@ -725,7 +729,7 @@ translate_compile_error (gint *errcode, const gchar **errmsg)
       break;
     }
 
-  g_assert (*errcode != 0);
+  g_assert (*errcode != -1);
   g_assert (*errmsg != NULL);
 }
 
diff --git a/glib/tests/regex.c b/glib/tests/regex.c
index 3355f64e5..9a1977b24 100644
--- a/glib/tests/regex.c
+++ b/glib/tests/regex.c
@@ -2187,6 +2187,18 @@ pcre2_ge (guint64 major, guint64 minor)
     return (pcre2_major > major) || (pcre2_major == major && pcre2_minor >= minor);
 }
 
+static void
+test_compile_errors (void)
+{
+  GRegex *regex;
+  GError *error = NULL;
+
+  regex = g_regex_new ("\\o{999}", G_REGEX_DEFAULT, G_REGEX_MATCH_DEFAULT, &error);
+  g_assert_null (regex);
+  g_assert_error (error, G_REGEX_ERROR, G_REGEX_ERROR_COMPILE);
+  g_clear_error (&error);
+}
+
 int
 main (int argc, char *argv[])
 {
@@ -2204,6 +2216,7 @@ main (int argc, char *argv[])
   g_test_add_func ("/regex/multiline", test_multiline);
   g_test_add_func ("/regex/explicit-crlf", test_explicit_crlf);
   g_test_add_func ("/regex/max-lookbehind", test_max_lookbehind);
+  g_test_add_func ("/regex/compile-errors", test_compile_errors);
 
   /* TEST_NEW(pattern, compile_opts, match_opts) */
 G_GNUC_BEGIN_IGNORE_DEPRECATIONS