Verify client shortcuts are unique

If you have two shortcuts that point to the same key combo, you'll get
"QAction::event: Ambiguous shortcut overload: <sequence>" in the logs
and neither action will be taken.

Add a test that scans the whole codebase to verify the argument to
setShortcut() is globally unique.

To make the test simple to write, standardize on a single way of writing
shortcuts, by adding Qt constants. A semgrep rule tries to guide people
into writing shortcuts in the same style, so the test can match them.

client/.semgrep/custom-rules.yml

@@ -180,3 +180,10 @@ rules:
     # Forbid any other use of assert
     - pattern-regex: |
         assert.*
+
+- id: enforce-setshortcut-style
+  patterns:
+    - pattern-regex: setShortcut\(QKeySequence(.*?)\)
+  message: "Use `Qt.* + Qt.*` style for setShortcut calls instead of QKeySequence (for test_shortcuts_are_unique test)"
+  languages: [python]
+  severity: WARNING

client/securedrop_client/gui/main.py

@@ -22,7 +22,7 @@
 from gettext import gettext as _
 
 from PyQt5.QtCore import Qt
-from PyQt5.QtGui import QClipboard, QGuiApplication, QIcon, QKeySequence
+from PyQt5.QtGui import QClipboard, QGuiApplication, QIcon
 from PyQt5.QtWidgets import QAction, QApplication, QHBoxLayout, QMainWindow, QVBoxLayout, QWidget
 
 from securedrop_client import __version__, state
@@ -93,7 +93,7 @@ def __init__(
         # Actions
         quit = QAction(_("Quit"), self)
         quit.setIcon(QIcon.fromTheme("application-exit"))
-        quit.setShortcut(QKeySequence.Quit)
+        quit.setShortcut(Qt.CTRL + Qt.Key_Q)
         quit.triggered.connect(self.close)
         self.addAction(quit)
 

client/securedrop_client/gui/widgets.py

@@ -36,7 +36,6 @@
     QFocusEvent,
     QFont,
     QIcon,
-    QKeySequence,
     QLinearGradient,
     QMouseEvent,
     QPalette,
@@ -3149,7 +3148,7 @@ def __init__(self, source: Source, controller: Controller) -> None:
         send_button_icon.addPixmap(load_image("send-disabled.svg"), QIcon.Disabled)
         self.send_button.setIcon(send_button_icon)
         self.send_button.setIconSize(QSize(56, 47))
-        self.send_button.setShortcut(QKeySequence("Ctrl+Return"))
+        self.send_button.setShortcut(Qt.CTRL + Qt.Key_Return)
         self.send_button.setDefault(True)
 
         # Set cursor.

client/tests/gui/test_shortcuts.py

@@ -0,0 +1,24 @@
+import re
+from collections import defaultdict
+from pathlib import Path
+
+
+def test_shortcuts_are_unique(mocker):
+    """
+    Look through the codebase for setShortcut() calls,
+    verify the argument passed is unique
+
+    The `enforce-setshortcut-style` semgrep rule enforces a consistent style
+    """
+    root = Path(__file__).parent.parent.parent / "securedrop_client"
+    shortcuts = defaultdict(int)
+    for path in root.glob("**/*.py"):
+        for match_ in re.findall(r"setShortcut\((.*)\)", path.read_text()):
+            shortcuts[match_] += 1
+
+    # Verify that the parsing actually found stuff
+    assert "Qt.CTRL + Qt.Key_Q" in shortcuts
+    # Look for duplicates
+    for shortcut, instances in shortcuts.items():
+        if instances > 1:
+            raise AssertionError(f"Shortcut {shortcut} is used {instances} times")