Fix escaping in snippets (#1362)

- Fixes #1323

## Checklist

- [x] I have added
[tests](https://www.cursorless.org/docs/contributing/test-case-recorder/)
- [ ] I have updated the
[docs](https://github.com/cursorless-dev/cursorless/tree/main/docs) and
[cheatsheet](https://github.com/cursorless-dev/cursorless/tree/main/cursorless-talon/src/cheatsheet)
- [ ] I have not broken the cheatsheet

Author: pokey

cursorless-talon-dev/src/cursorless_dev.talon

@@ -1,16 +1,23 @@
 tag: user.cursorless
 -
 
-{user.cursorless_homophone} record: user.run_rpc_command("cursorless.recordTestCase")
-{user.cursorless_homophone} pause: user.run_rpc_command("cursorless.pauseRecording")
-{user.cursorless_homophone} resume: user.run_rpc_command("cursorless.resumeRecording")
+{user.cursorless_homophone} record:
+    user.run_rpc_command("cursorless.recordTestCase")
+{user.cursorless_homophone} pause:
+    user.run_rpc_command("cursorless.pauseRecording")
+{user.cursorless_homophone} resume:
+    user.run_rpc_command("cursorless.resumeRecording")
 
 {user.cursorless_homophone} record navigation:
     user.cursorless_record_navigation_test()
 {user.cursorless_homophone} record error: user.cursorless_record_error_test()
 {user.cursorless_homophone} record highlights:
     user.cursorless_record_highlights_test()
 {user.cursorless_homophone} record that mark:
+    user.cursorless_record_that_mark_test()
 
 {user.cursorless_homophone} update cheatsheet:
-  user.cursorless_cheat_sheet_update_json()
+    user.cursorless_cheat_sheet_update_json()
+
+test snippet make <user.cursorless_target>:
+    user.cursorless_single_target_command_no_wait("generateSnippet", cursorless_target, "testSnippet")

packages/cursorless-engine/src/actions/GenerateSnippet/GenerateSnippet.ts

@@ -1,8 +1,9 @@
 import { FlashStyle, isTesting, Range } from "@cursorless/common";
 import { Offsets } from "../../processTargets/modifiers/surroundingPair/types";
 import { ide } from "../../singletons/ide.singleton";
-import { Target } from "../../typings/target.types";
 import { Graph } from "../../typings/Graph";
+import { Target } from "../../typings/target.types";
+import { matchAll } from "../../util/regex";
 import { ensureSingleTarget, flashTargets } from "../../util/targetUtils";
 import { Action, ActionReturnValue } from "../actions.types";
 import { constructSnippetBody } from "./constructSnippetBody";
@@ -114,10 +115,22 @@ export default class GenerateSnippet implements Action {
       ),
     );
 
-    /** The text of the snippet, with placeholders inserted for variables */
-    const snippetBodyText = editText(
-      editor.document.getText(target.contentRange),
-      variables.map(({ offsets, defaultName, placeholderIndex }) => ({
+    const originalText = editor.document.getText(target.contentRange);
+
+    /**
+     * The text of the snippet, with placeholders inserted for variables and
+     * special characters `$`, `\`, and `}` escaped twice to make it through
+     * both meta snippet and user snippet.
+     */
+    const snippetBodyText = editText(originalText, [
+      ...matchAll(originalText, /\$|\\/g, (match) => ({
+        offsets: {
+          start: match.index!,
+          end: match.index! + match[0].length,
+        },
+        text: match[0] === "\\" ? `\\${match[0]}` : `\\\\${match[0]}`,
+      })),
+      ...variables.map(({ offsets, defaultName, placeholderIndex }) => ({
         offsets,
         // Note that the reason we use the substituter here is primarily so
         // that the `\` below doesn't get escaped upon conversion to json.
@@ -140,7 +153,7 @@ export default class GenerateSnippet implements Action {
           ].join(""),
         ),
       })),
-    );
+    ]);
 
     const snippetLines = constructSnippetBody(snippetBodyText, linePrefix);
 

packages/cursorless-vscode-e2e/src/suite/fixtures/recorded/actions/snippets/testSnippetMakeLine.yml

@@ -0,0 +1,53 @@
+languageId: plaintext
+command:
+  version: 4
+  spokenForm: test snippet make line
+  action:
+    name: generateSnippet
+    args: [testSnippet]
+  targets:
+    - type: primitive
+      modifiers:
+        - type: containingScope
+          scopeType: {type: line}
+  usePrePhraseSnapshot: true
+initialState:
+  documentContents: \textbf{$foo}
+  selections:
+    - anchor: {line: 0, character: 9}
+      active: {line: 0, character: 12}
+  marks: {}
+finalState:
+  documentContents: |-
+    {
+      "testSnippet": {
+        "definitions": [
+          {
+            "scope": {
+              "langIds": [
+                "plaintext"
+              ]
+            },
+            "body": [
+              "\\textbf{\\$$variable1}"
+            ]
+          }
+        ],
+        "description": "",
+        "variables": {
+          "variable1": {}
+        }
+      }
+    }
+  selections:
+    - anchor: {line: 10, character: 24}
+      active: {line: 10, character: 33}
+    - anchor: {line: 16, character: 7}
+      active: {line: 16, character: 16}
+  thatMark:
+    - type: UntypedTarget
+      contentRange:
+        start: {line: 0, character: 0}
+        end: {line: 0, character: 13}
+      isReversed: false
+      hasExplicitRange: true