fix: stop $ sequences in selected text corrupting the prompt

test/build-url.test.js

@@ -133,3 +133,43 @@ test("a query needing no truncation is left byte-identical", () => {
   const raw = "a modest question about thermodynamics";
   assert.equal(queryOf(buildChatGptUrl(DEFAULT_SETTINGS, raw)), raw);
 });
+
+// String.prototype.replaceAll gives $&, $`, $', and $$ special meaning in the
+// REPLACEMENT string, and `query` (arbitrary page-selected text) is exactly
+// that argument. These selections are ordinary shell one-liners, not
+// adversarial input, and must round-trip byte-identically into `q`.
+test("a selection containing $& survives the default {query} template byte-identically", () => {
+  const raw = "awk print $& here";
+  const url = buildChatGptUrl(DEFAULT_SETTINGS, raw);
+  assert.equal(queryOf(url), raw);
+});
+
+test("a selection containing $& survives a prefix template byte-identically", () => {
+  const raw = "awk print $& here";
+  const url = buildChatGptUrl(withSettings({ promptTemplate: "Explain: {query}" }), raw);
+  assert.equal(queryOf(url), `Explain: ${raw}`);
+});
+
+test("a selection containing $` and $' survives the default {query} template byte-identically", () => {
+  const raw = "shell $` and $' here";
+  const url = buildChatGptUrl(DEFAULT_SETTINGS, raw);
+  assert.equal(queryOf(url), raw);
+});
+
+test("a selection containing $` and $' survives a prefix template byte-identically", () => {
+  const raw = "shell $` and $' here";
+  const url = buildChatGptUrl(withSettings({ promptTemplate: "Explain: {query}" }), raw);
+  assert.equal(queryOf(url), `Explain: ${raw}`);
+});
+
+test("a selection containing $$ survives the default {query} template byte-identically", () => {
+  const raw = "PID is $$ in bash";
+  const url = buildChatGptUrl(DEFAULT_SETTINGS, raw);
+  assert.equal(queryOf(url), raw);
+});
+
+test("a selection containing $$ survives a prefix template byte-identically", () => {
+  const raw = "PID is $$ in bash";
+  const url = buildChatGptUrl(withSettings({ promptTemplate: "Explain: {query}" }), raw);
+  assert.equal(queryOf(url), `Explain: ${raw}`);
+});