fix(extension-api): reject key chords with empty + segments

.changeset/reject-empty-keychord-segments.md

@@ -0,0 +1,5 @@
+---
+"hunkdiff": patch
+---
+
+Reject malformed configured and extension key chords instead of silently rebinding them after empty `+` segments.

src/extension-api/keys.test.ts

@@ -87,6 +87,28 @@ describe("parseKeyChord", () => {
     expect(parseKeyChord("")).toHaveProperty("error");
   });
 
+  test("refuses chords with an empty segment around +", () => {
+    expect(parseKeyChord("s+")).toHaveProperty("error");
+    expect(parseKeyChord("+s")).toHaveProperty("error");
+    expect(parseKeyChord("ctrl++s")).toHaveProperty("error");
+    expect(parseKeyChord("ctrl+s+")).toHaveProperty("error");
+  });
+
+  test("keeps the literal plus key valid, with or without surrounding whitespace", () => {
+    expect(parsed("+")).toEqual({
+      base: "+",
+      ctrl: false,
+      meta: false,
+      option: false,
+      shift: false,
+    });
+    expect(parsed(" + ")).toEqual(parsed("+"));
+  });
+
+  test("tolerates whitespace around otherwise valid chord components", () => {
+    expect(parsed("ctrl + s")).toEqual(parsed("ctrl+s"));
+  });
+
   test("refuses shift on symbols and digits, keeps it for letters and named keys", () => {
     // Shifted symbols have no layout-independent identity; the binding must
     // name the character shift produces instead.

src/extension-api/keys.ts

@@ -70,15 +70,19 @@ const MODIFIER_TOKENS: Record<string, keyof Omit<ParsedKeyChord, "base">> = {
  * registration instead of silently never firing.
  */
 export function parseKeyChord(chord: string): ParsedKeyChord | { error: string } {
-  const tokens = chord
-    .split("+")
-    .map((token) => token.trim())
-    .filter((token) => token.length > 0);
-  // A literal "+" binding arrives as empty tokens; treat the lone "+" specially.
-  if (tokens.length === 0) {
-    return chord.trim() === "+"
-      ? { base: "+", ctrl: false, meta: false, option: false, shift: false }
-      : { error: `Empty key chord "${chord}"` };
+  // The literal "+" binding (optionally whitespace-padded) splits into two
+  // empty segments; recognize it before empty segments are rejected below.
+  if (chord.trim() === "+") {
+    return { base: "+", ctrl: false, meta: false, option: false, shift: false };
+  }
+
+  if (chord.trim().length === 0) {
+    return { error: `Empty key chord "${chord}"` };
+  }
+
+  const tokens = chord.split("+").map((token) => token.trim());
+  if (tokens.some((token) => token.length === 0)) {
+    return { error: `Key chord "${chord}" has an empty segment around "+"` };
   }
 
   const parsed: ParsedKeyChord = {

src/ui/lib/keymap.test.ts

@@ -106,6 +106,16 @@ describe("resolveCommandKeys", () => {
     expect(issues[0]?.message).toContain("not a usable key chord");
   });
 
+  test("a malformed chord with an empty + segment does not claim another command's shortcut", () => {
+    const { keys, issues } = resolve({ "hunk.app.quit": ["s+", "ctrl+q"] });
+
+    expect(keys.get("hunk.app.quit")).toEqual(["ctrl+q"]);
+    // "s+" must not be normalized into "s" and steal it from its default owner.
+    expect(keys.get("hunk.view.toggleFilesPane")).toEqual(["s"]);
+    expect(issues).toHaveLength(1);
+    expect(issues[0]?.message).toContain("not a usable key chord");
+  });
+
   test("unknown ids are reported, softly when they look like extension commands", () => {
     const { keys, issues } = resolve({ "hunk.app.quti": "x", "ghost.command": "z" });