Merge pull request #378 from vkbo/exceptions

Exception Handling

nw/__init__.py

@@ -34,6 +34,7 @@ from os import path, remove, rename
 from PyQt5.QtGui import QIcon
 from PyQt5.QtWidgets import QApplication, QErrorMessage
 
+from nw.error import exceptionHandler
 from nw.config import Config
 
 __package__    = "nw"
@@ -249,11 +250,12 @@ def main(sysArgs=None):
     if errorData:
         errApp = QApplication([])
         errMsg = QErrorMessage()
-        errMsg.setMinimumWidth(500)
-        errMsg.setMinimumHeight(300)
+        errMsg.resize(500, 300)
         errMsg.showMessage((
-            "ERROR: novelWriter cannot start due to the following issues:<br><br>"
-            "&nbsp;-&nbsp;%s<br><br>Exiting."
+            "<h3>A critical error has been encountered</h3>"
+            "<p>novelWriter cannot start due to the following issues:<p>"
+            "<p>&nbsp;-&nbsp;%s</p>"
+            "<p>Shutting down ...</p>"
         ) % (
             "<br>&nbsp;-&nbsp;".join(errorData)
         ))
@@ -276,34 +278,44 @@ def main(sysArgs=None):
         nwApp.setWindowIcon(QIcon(CONFIG.appIcon))
         nwApp.setOrganizationDomain(__domain__)
 
+        # We try to catch critical errors while setting up the main GUI
+        # by wrapping the main GUI in a try/except structure. This will
+        # not catch all exceptions for other parts of the application.
+        # For all other unhandled exceptions, we use a custom exception
+        # handler that pops a dialog box with the error message.
+        sys.excepthook = exceptionHandler
+
         try:
             nwGUI = GuiMain()
             sys.exit(nwApp.exec_())
 
         except Exception:
-            # novelWriter has crashed!
-            from traceback import print_tb, format_tb
 
-            eInfo = sys.exc_info()
-            logger.critical("%s: %s" % (eInfo[0].__name__, eInfo[1]))
-            print_tb(eInfo[2])
+            from traceback import print_tb
+            from nw.error import formatHtmlErrMsg
 
-            del nwApp
+            exType, exValue, exTrace = sys.exc_info()
 
-            errApp = QApplication([])
-            errMsg = QErrorMessage()
-            errMsg.setWindowTitle("Critical Error")
-            errMsg.setMinimumWidth(500)
-            errMsg.setMinimumHeight(300)
-            errMsg.showMessage((
-                "<h3>novelWriter has encountered a critical error!</h3>"
-                "<p><b>%s:</b><br>%s</p>"
-                "<p><b>Traceback:</b><br>%s</p>"
-                "<p>Shutting down ...</p>"
-            ) % (eInfo[0].__name__, eInfo[1], "<br>".join(format_tb(eInfo[2]))))
-            errApp.exec_()
+            logger.critical("%s: %s" % (exType.__name__, str(exValue)))
+            print_tb(exTrace)
 
-            del eInfo
+            try:
+                del nwApp
+
+                errApp = QApplication([])
+                errMsg = QErrorMessage()
+                errMsg.setWindowTitle("Critical Error")
+                errMsg.resize(800, 400)
+                errMsg.showMessage((
+                    "<h3>A critical error has been encountered</h3>"
+                    "%s"
+                    "<p>Shutting down ...</p>"
+                ) % formatHtmlErrMsg(exType, exValue, exTrace))
+                errApp.exec_()
+
+            except Exception as e:
+                logger.critical("Could not create error message dialog.")
+                logger.critical(str(e))
 
             sys.exit(1)
 

nw/error.py

@@ -0,0 +1,111 @@
+# -*- coding: utf-8 -*-
+"""novelWriter Init
+
+ novelWriter – Exception Handling
+==================================
+ Error handling functions
+
+ File History:
+ Created: 2020-08-02 [0.10.2]
+
+ This file is a part of novelWriter
+ Copyright 2020, Veronica Berglyd Olsen
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <https://www.gnu.org/licenses/>.
+"""
+
+def formatHtmlErrMsg(exType, exValue, exTrace):
+    """Generates a HTML version of an exception.
+    """
+    try:
+        import sys
+        from traceback import format_tb
+        from nw import __issuesurl__, __version__
+        from PyQt5.Qt import PYQT_VERSION_STR
+        from PyQt5.QtCore import QT_VERSION_STR, QSysInfo
+
+        fmtTrace = ""
+        for trEntry in format_tb(exTrace):
+            for trLine in trEntry.split("\n"):
+                stripLine = trLine.lstrip(" ")
+                nIndent = len(trLine) - len(stripLine)
+                fmtTrace += "&nbsp;"*nIndent + stripLine + "<br>"
+
+        theMessage = (
+            "<p>Please report this error by submitting an issue report on "
+            "GitHub, providing a description and this error message. "
+            "URL: &lt;{issueUrl}&gt;.</p>"
+            "<p><b>Environment</b><br>Version: {nwVersion}, OS: {osType} ({osKernel}),"
+            "Python: {pyVersion} ({pyHexVer:#x}), Qt: {qtVers}, PyQt: {pyqtVers}</p>"
+            "<p><b>Error Type</b><br>{exType}: {exMessage}</p>"
+            "<p><b>Traceback</b><br>{exTrace}</p>"
+        ).format(
+            nwVersion = __version__,
+            osType    = sys.platform,
+            osKernel  = QSysInfo.kernelVersion(),
+            pyVersion = sys.version.split()[0],
+            pyHexVer  = sys.hexversion,
+            qtVers    = QT_VERSION_STR,
+            pyqtVers  = PYQT_VERSION_STR,
+            issueUrl  = __issuesurl__,
+            exType    = exType.__name__,
+            exMessage = str(exValue),
+            exTrace   = fmtTrace
+        )
+
+        return theMessage
+
+    except Exception as e:
+        return "Could not generate error message.<br>%s" % str(e)
+
+    return "Could not generate error message."
+
+
+def exceptionHandler(exType, exValue, exTrace):
+    """Function to catch unhandled global exceptions.
+    """
+    import logging
+    from traceback import print_tb, format_tb
+    from nw import CONFIG
+    from PyQt5.QtWidgets import qApp, QApplication, QErrorMessage, QMessageBox
+
+    logger = logging.getLogger(__name__)
+    logger.error("%s: %s" % (exType.__name__, str(exValue)))
+    print_tb(exTrace)
+
+    if not CONFIG.showGUI:
+        return
+
+    try:
+        nwGUI = None
+        for qWin in qApp.topLevelWidgets():
+            if qWin.objectName() == "GuiMain":
+                nwGUI = qWin
+                break
+
+        if nwGUI is None:
+            logger.warning("Could not find main GUI window so cannot open error dialog")
+            return
+
+        errMsg = QErrorMessage(nwGUI)
+        errMsg.setWindowTitle("Unhandled Error")
+        errMsg.resize(800, 400)
+        errMsg.showMessage((
+            "<h3>An unhandled error has been encountered</h3>%s"
+        ) % formatHtmlErrMsg(exType, exValue, exTrace))
+
+    except Exception as e:
+        logger.error(str(e))
+
+    return

nw/gui/build.py

@@ -432,7 +432,6 @@ class GuiBuildNovel(QDialog):
     def _buildPreview(self):
         """Build a preview of the project in the document viewer.
         """
-
         # Get Settings
         fmtTitle      = self.fmtTitle.text().strip()
         fmtChapter    = self.fmtChapter.text().strip()

nw/guimain.py

@@ -56,6 +56,7 @@ class GuiMain(QMainWindow):
         QMainWindow.__init__(self)
 
         logger.debug("Initialising GUI ...")
+        self.setObjectName("GuiMain")
         self.mainConf = nw.CONFIG
 
         # Some runtime info useful for debugging