Merge branch 'add-g-log-get-always-fatal' into 'main'

gmessages: Add 'g_log_get_always_fatal()' for use in custom log writers

Closes #2544

See merge request GNOME/glib!4546

glib/gbacktrace.c

@@ -140,7 +140,7 @@ volatile gboolean glib_on_error_halt = TRUE;
  * This function may cause different actions on non-UNIX platforms.
  *
  * On Windows consider using the `G_DEBUGGER` environment
- * variable (see [Running GLib Applications](glib-running.html)) and
+ * variable (see [Running GLib Applications](running.html)) and
  * calling g_on_error_stack_trace() instead.
  */
 void
@@ -243,7 +243,7 @@ g_on_error_query (const gchar *prg_name)
  * g_on_error_query(). If called directly, it will raise an
  * exception, which will crash the program. If the `G_DEBUGGER` environment
  * variable is set, a debugger will be invoked to attach and
- * handle that exception (see [Running GLib Applications](glib-running.html)).
+ * handle that exception (see [Running GLib Applications](running.html)).
  */
 void
 g_on_error_stack_trace (const gchar *prg_name)

glib/gmessages.c

@@ -219,7 +219,7 @@
  *
  * You can make warnings fatal at runtime by setting the `G_DEBUG`
  * environment variable (see
- * [Running GLib Applications](glib-running.html)):
+ * [Running GLib Applications](running.html)):
  *
  * ```
  * G_DEBUG=fatal-warnings gdb ./my-program
@@ -254,7 +254,7 @@
  *
  * You can make critical warnings fatal at runtime by
  * setting the `G_DEBUG` environment variable (see
- * [Running GLib Applications](glib-running.html)):
+ * [Running GLib Applications](running.html)):
  *
  * ```
  * G_DEBUG=fatal-warnings gdb ./my-program
@@ -557,6 +557,48 @@ g_log_domain_get_handler_L (GLogDomain	*domain,
   return default_log_func;
 }
 
+/**
+ * g_log_get_always_fatal:
+ *
+ * Gets the current fatal mask.
+ *
+ * This is mostly used by custom log writers to make fatal messages
+ * (`fatal-warnings`, `fatal-criticals`) work as expected, when using the
+ * `G_DEBUG` environment variable (see [Running GLib Applications](running.html)).
+ *
+ * An example usage is shown below:
+ *
+ * ```c
+ * static GLogWriterOutput
+ * my_custom_log_writer_fn (GLogLevelFlags log_level,
+ *                          const GLogField *fields,
+ *                          gsize n_fields,
+ *                          gpointer user_data)
+ * {
+ *
+ *    // abort if the message was fatal
+ *    if (log_level & g_log_get_always_fatal ())
+ *      g_abort ();
+ *
+ *    // custom log handling code
+ *    ...
+ *    ...
+ *
+ *    // success
+ *    return G_LOG_WRITER_HANDLED;
+ * }
+ * ```
+ *
+ * Returns: the current fatal mask
+ *
+ * Since: 2.86
+ */
+GLogLevelFlags
+g_log_get_always_fatal (void)
+{
+  return g_log_always_fatal;
+}
+
 /**
  * g_log_set_always_fatal:
  * @fatal_mask: the mask containing bits set for each level of error which is
@@ -570,7 +612,7 @@ g_log_domain_get_handler_L (GLogDomain	*domain,
  *
  * You can also make some message levels fatal at runtime by setting
  * the `G_DEBUG` environment variable (see
- * [Running GLib Applications](glib-running.html)).
+ * [Running GLib Applications](running.html)).
  *
  * Libraries should not call this function, as it affects all messages logged
  * by a process, including those from other libraries.

glib/gmessages.h

@@ -117,6 +117,9 @@ GLogLevelFlags  g_log_set_fatal_mask    (const gchar    *log_domain,
 GLIB_AVAILABLE_IN_ALL
 GLogLevelFlags  g_log_set_always_fatal  (GLogLevelFlags  fatal_mask);
 
+GLIB_AVAILABLE_IN_2_86
+GLogLevelFlags  g_log_get_always_fatal  (void);
+
 /* Structured logging mechanism. */
 
 /**
@@ -587,7 +590,7 @@ GPrintFunc      g_set_printerr_handler  (GPrintFunc      func);
  *
  * To debug failure of a g_return_if_fail() check, run the code under a debugger
  * with `G_DEBUG=fatal-criticals` or `G_DEBUG=fatal-warnings` defined in the
- * environment (see [Running GLib Applications](glib-running.html)):
+ * environment (see [Running GLib Applications](running.html)):
  *
  * |[
  *   G_DEBUG=fatal-warnings gdb ./my-program

glib/tests/logging.c

@@ -643,6 +643,17 @@ test_fatal_log_mask (void)
   g_test_trap_assert_stdout_unmatched ("*fatal*");
 }
 
+static void
+test_always_fatal (void)
+{
+  GLogLevelFlags log_level;
+
+  log_level = G_LOG_LEVEL_CRITICAL | G_LOG_LEVEL_WARNING;
+  g_log_set_always_fatal (log_level);
+
+  g_assert_cmpint (g_log_get_always_fatal (), ==, log_level | G_LOG_LEVEL_ERROR);
+}
+
 static gint my_print_count = 0;
 static void
 my_print_handler (const gchar *text)
@@ -1168,6 +1179,7 @@ main (int argc, char *argv[])
   g_test_add_func ("/logging/journald-handler", test_journald_handler);
   g_test_add_func ("/logging/warnings", test_warnings);
   g_test_add_func ("/logging/fatal-log-mask", test_fatal_log_mask);
+  g_test_add_func ("/logging/always-fatal", test_always_fatal);
   g_test_add_func ("/logging/set-handler", test_set_handler);
   g_test_add_func ("/logging/print-handler", test_print_handler);
   g_test_add_func ("/logging/printerr-handler", test_printerr_handler);