From 5253c7eb8b39a82d0232828b7b1cff4c5622ce0a Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Tue, 31 Mar 2020 18:26:54 +0200
Subject: [PATCH] Tweak error-dump (when session load fails)

When limiting the message count (e.g. for display in a dialog),
use reverse order, and only print errors.

When loading a session fails, the most recent error is
more likely the real cause.
---
 libs/gtkmm2ext/gtk_ui.cc | 32 ++++++++++++++++++++++++++++----
 1 file changed, 28 insertions(+), 4 deletions(-)

diff --git a/libs/gtkmm2ext/gtk_ui.cc b/libs/gtkmm2ext/gtk_ui.cc
index e38ba71d45..067f712198 100644
--- a/libs/gtkmm2ext/gtk_ui.cc
+++ b/libs/gtkmm2ext/gtk_ui.cc
@@ -514,16 +514,40 @@ void
 UI::dump_errors (std::ostream& ostr, size_t limit)
 {
 	Glib::Threads::Mutex::Lock lm (error_lock);
-	ostr << endl << X_("Errors/Messages:") << endl;
-	for (list<string>::const_iterator i = error_stack.begin(); i != error_stack.end(); ++i) {
-		ostr << *i << endl;
-		if (limit > 0) {
+	bool first = true;
+
+	if (limit > 0) {
+		/* reverse listing, Errors only */
+		for (list<string>::const_reverse_iterator i = error_stack.rbegin(); i != error_stack.rend(); ++i) {
+			if ((*i).substr (0, 9) == X_("WARNING: ") || (*i).substr (0, 6) == X_("INFO: ")) {
+				continue;
+			}
+			if (first) {
+				first = false;
+			}
+			ostr << *i << endl;
 			if (--limit == 0) {
 				ostr << "..." << endl;
 				break;
 			}
 		}
 	}
+
+	if (first) {
+		for (list<string>::const_iterator i = error_stack.begin(); i != error_stack.end(); ++i) {
+			if (first) {
+				ostr << endl << X_("Log Messages:") << endl;
+				first = false;
+			}
+			ostr << *i << endl;
+			if (limit > 0) {
+				if (--limit == 0) {
+					ostr << "..." << endl;
+					break;
+				}
+			}
+		}
+	}
 	ostr << endl;
 }