Fix infinite search loop bug (#1016)

* Make sure the search loop in the editor cannot run infinitely
* Add test coverage of infinite search case
* Run GitHub actions against the patch branch

.github/workflows/syntax.yml

@@ -4,9 +4,11 @@ on:
   push:
     branches: 
       - main
+      - patch
   pull_request:
     branches:
       - main
+      - patch
 
 jobs:
   checkSyntax:

.github/workflows/test_linux.yml

@@ -4,9 +4,11 @@ on:
   push:
     branches: 
       - main
+      - patch
   pull_request:
     branches:
       - main
+      - patch
 
 jobs:
   testLinux:

.github/workflows/test_mac.yml

@@ -4,9 +4,11 @@ on:
   push:
     branches: 
       - main
+      - patch
   pull_request:
     branches:
       - main
+      - patch
 
 jobs:
   testMac:

.github/workflows/test_win.yml

@@ -4,9 +4,11 @@ on:
   push:
     branches: 
       - main
+      - patch
   pull_request:
     branches:
       - main
+      - patch
 
 jobs:
   testWin:

novelwriter/gui/doceditor.py

@@ -1436,10 +1436,16 @@ class GuiDocEditor(QTextEdit):
         theCursor.setPosition(0)
         self.setTextCursor(theCursor)
 
-        while self.find(searchFor, findOpt):
+        # Search up to a maximum of 1000, and make sure certain special
+        # searches like a regex search for .* turns into an infinite loop
+        while self.find(searchFor, findOpt) and len(resE) <= 1000:
             theCursor = self.textCursor()
-            resS.append(theCursor.selectionStart())
+            if theCursor.hasSelection():
-            resE.append(theCursor.selectionEnd())
+                resS.append(theCursor.selectionStart())
+                resE.append(theCursor.selectionEnd())
+            else:
+                logger.warning("The search returned an empty result")
+                break
 
         if hasSelection:
             theCursor.setPosition(origA, QTextCursor.MoveAnchor)
@@ -2410,7 +2416,7 @@ class GuiDocEditSearch(QFrame):
         """Set the count values for the current search.
         """
         currRes = "?" if currRes is None else currRes
-        resCount = "?" if resCount is None else resCount
+        resCount = "?" if resCount is None else "1000+" if resCount > 1000 else resCount
         minWidth = self.theTheme.getTextWidth(f"{resCount}//{resCount}", self.boxFont)
         self.resultLabel.setText(f"{currRes}/{resCount}")
         self.resultLabel.setMinimumWidth(minWidth)

tests/test_gui/test_gui_doceditor.py

@@ -1286,13 +1286,13 @@ def testGuiEditor_Search(qtbot, monkeypatch, nwGUI, nwLipsum):
     monkeypatch.setattr(GuiDocEditor, "hasFocus", lambda *a: True)
 
     nwGUI.theProject.projTree.setSeed(42)
-    assert nwGUI.openProject(nwLipsum)
+    assert nwGUI.openProject(nwLipsum) is True
-    assert nwGUI.openDocument("4c4f28287af27")
+    assert nwGUI.openDocument("4c4f28287af27") is True
     origText = nwGUI.docEditor.getText()
     qtbot.wait(stepDelay)
 
     # Select the Word "est"
-    assert nwGUI.docEditor.setCursorPosition(630)
+    nwGUI.docEditor.setCursorPosition(630)
     nwGUI.docEditor._makeSelection(QTextCursor.WordUnderCursor)
     theCursor = nwGUI.docEditor.textCursor()
     assert theCursor.selectedText() == "est"
@@ -1331,7 +1331,7 @@ def testGuiEditor_Search(qtbot, monkeypatch, nwGUI, nwLipsum):
     assert nwGUI.docEditor.docSearch.isVisible() is True
 
     # Search for non-existing
-    assert nwGUI.docEditor.setCursorPosition(0)
+    nwGUI.docEditor.setCursorPosition(0)
     assert nwGUI.docEditor.docSearch.setSearchText("abcdef")
     qtbot.mouseClick(nwGUI.docEditor.docSearch.searchButton, Qt.LeftButton, delay=keyDelay)
     assert nwGUI.docEditor.getCursorPosition() < 3  # No result
@@ -1342,11 +1342,18 @@ def testGuiEditor_Search(qtbot, monkeypatch, nwGUI, nwLipsum):
     assert nwGUI.docEditor.docSearch.isRegEx is True
 
     # Set invalid RegEx
-    assert nwGUI.docEditor.setCursorPosition(0)
+    nwGUI.docEditor.setCursorPosition(0)
     assert nwGUI.docEditor.docSearch.setSearchText(r"\bSus[")
     qtbot.mouseClick(nwGUI.docEditor.docSearch.searchButton, Qt.LeftButton, delay=keyDelay)
     assert nwGUI.docEditor.getCursorPosition() < 3  # No result
 
+    # Set dangerous RegEx (issue #1015)
+    # If this doesn't get caught, the app will hang
+    nwGUI.docEditor.setCursorPosition(0)
+    assert nwGUI.docEditor.docSearch.setSearchText(r".*")
+    qtbot.mouseClick(nwGUI.docEditor.docSearch.searchButton, Qt.LeftButton, delay=keyDelay)
+    assert abs(nwGUI.docEditor.getCursorPosition() - 14) < 3
+
     # Set valid RegEx
     assert nwGUI.docEditor.docSearch.setSearchText(r"\bSus")
     qtbot.mouseClick(nwGUI.docEditor.docSearch.searchButton, Qt.LeftButton, delay=keyDelay)