Fix internal error handling in non-main threads.

doc/changelog.txt

@@ -10,6 +10,8 @@ Fixes:
 - logging: Correctly encode CSV output.
   Closes: SF bug #3263848
 - logging: Don't print empty country information.
+- gui: Don't crash while handling internal error in threads other than
+  the main thread.
 
 Changes:
 - gui: Improved display of internal errors.

linkcheck/gui/__init__.py

@@ -51,6 +51,7 @@ class LinkCheckerMain (QtGui.QMainWindow, Ui_MainWindow):
 
     log_url_signal = QtCore.pyqtSignal(object)
     log_stats_signal = QtCore.pyqtSignal(object)
+    error_signal = QtCore.pyqtSignal(str)
 
     def __init__(self, parent=None, url=None):
         """Initialize UI."""
@@ -119,6 +120,7 @@ class LinkCheckerMain (QtGui.QMainWindow, Ui_MainWindow):
         self.checker.terminated.connect(set_idle)
         self.log_url_signal.connect(self.model.log_url)
         self.log_stats_signal.connect(self.log_stats)
+        self.error_signal.connect(self.internal_error)
 
     def init_treeview (self):
         """Set treeview model and layout."""
@@ -376,3 +378,7 @@ Version 2 or later.
     def log_stats (self, statistics):
         """Set statistic information for selected URL."""
         set_statistics(self, statistics)
+
+    def internal_error (self, msg):
+        """Display internal error message. Triggered by sys.excepthook()."""
+        QtGui.QMessageBox.warning(self, _(u"LinkChecker internal error"), msg)

linkchecker-gui

@@ -19,7 +19,7 @@
 Check HTML pages for broken links. This is the GUI client.
 """
 import sys
-from PyQt4.QtGui import QApplication, QStyleFactory, QMessageBox
+from PyQt4.QtGui import QApplication, QStyleFactory
 from linkcheck.gui import LinkCheckerMain
 from linkcheck import configuration, drop_privileges, i18n
 
@@ -29,8 +29,7 @@ def excepthook (parent, etype, evalue, tb):
     from linkcheck.director.console import internal_error
     out = i18n.get_encoded_writer(out=StringIO(), encoding="utf-8")
     internal_error(out=out, etype=etype, evalue=evalue, tb=tb)
-    QMessageBox.warning(parent, _(u"LinkChecker internal error"),
-        out.getvalue())
+    parent.error_signal.emit(out.getvalue())
 
 ## Look and feel with stylesheets
 # In Cleanlooks the progress bar text is outside the bar.