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

1 files changed, 6 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);
 }