Mypy config changes & enable a few more checks

.github/workflows/tests.yml

@@ -65,7 +65,7 @@ jobs:
     - run: ruff check
 
     - name: Run mypy (only PyQt6 + recent Python)
-      run: mypy gitfourchette
+      run: mypy
       if: ${{ matrix.qt == 'pyqt6' && matrix.py >= '3.13' }}
 
     - name: Unit tests

gitfourchette/filelists/filelistmodel.py

@@ -306,7 +306,7 @@ def matchPathspec(self, pattern: str) -> str:
             return next(d.new.path for d in self.deltas if d.new.matchPathspec(pattern))
 
         # Try old side (but return path from *new* side)
-        with suppress(StopIteration):
+        with suppress(StopIteration):  # type: ignore[unreachable]
             return next(d.new.path for d in self.deltas if d.old.matchPathspec(pattern))
 
         return ""

gitfourchette/gitdriver/gitdriver.py

@@ -323,7 +323,7 @@ def diffFormattingArgs() -> list[str]:
             return ["--ignore-all-space"]
         if m == WhitespaceMode.IgnoreCrAtEol:
             return ["--ignore-cr-at-eol"]
-        return []
+        raise NotImplementedError(f"unsupported WhitespaceMode {m}")
 
     @classmethod
     def buildDiffCommand(
@@ -367,7 +367,7 @@ def buildDiffCommand(
             tokens.append(str(b))
 
         else:
-            assert delta is None
+            assert delta is None  # type: ignore[unreachable]
 
         return tokens
 

gitfourchette/graph/graphbuilder.py

@@ -276,7 +276,7 @@ def _stabilizeTrickle(trickle: GraphTrickle, startRow: int, newCommitSequence: l
 
             # See if finished (not too often - expensive)
             if ((row & 0xFF) == 0) and trickle.done:
-                return row
+                return row  # type: ignore[unreachable]
 
     @property
     def hiddenCommits(self):