prompts: avoid wrapping file attachments in code fences (#569)

* prompts: avoid wrapping file attachments in code fences

We previously included attached files like this

```
<attachment id="test.js" filePath="/home/jola/test.js">
\```javascript
bar

asd (
\```
</attachment>
```

Which, very reasonably, caused the model to get confused and think that
the file actually contained those backticks. This change removes that
so that it's just

```
<attachment id="test.js" filePath="/home/jola/test.js">
bar

asd (
</attachment>
```

Refs microsoft/vscode#260772 (comment)

Busted all the caches with associated baseline noise.

* fixup

Author: connor4312

src/extension/prompts/node/agent/test/__snapshots__/agentPrompt.spec.tsx.snap

@@ -345,13 +345,11 @@ copilot_cache_control: { type: 'ephemeral' }
 ~~~md
 <attachments>
 <attachment id="file" filePath="/workspace/file.ts">
-\`\`\`ts
 line 1
 line 2
 
 line 4
 line 5
-\`\`\`
 </attachment>
 
 </attachments>
@@ -829,13 +827,11 @@ copilot_cache_control: { type: 'ephemeral' }
 ~~~md
 <attachments>
 <attachment id="file" filePath="/workspace/file.ts">
-\`\`\`ts
 line 1
 line 2
 
 line 4
 line 5
-\`\`\`
 </attachment>
 
 </attachments>
@@ -1021,13 +1017,11 @@ copilot_cache_control: { type: 'ephemeral' }
 ~~~md
 <attachments>
 <attachment id="file" filePath="/workspace/file.ts">
-\`\`\`ts
 line 1
 line 2
 
 line 4
 line 5
-\`\`\`
 </attachment>
 
 </attachments>

src/extension/prompts/node/agent/test/__snapshots__/summarization-duringToolCalling-FullSumm.spec.snap

@@ -2,13 +2,11 @@
 ~~~md
 <attachments>
 <attachment id="file" filePath="/workspace/file.ts">
-```ts
 line 1
 line 2
 
 line 4
 line 5
-```
 </attachment>
 
 </attachments>

src/extension/prompts/node/agent/test/__snapshots__/summarization-previousTurnMultiple-Agent.spec.snap

@@ -52,13 +52,11 @@ copilot_cache_control: { type: 'ephemeral' }
 ~~~md
 <attachments>
 <attachment id="file" filePath="/workspace/file.ts">
-```ts
 line 1
 line 2
 
 line 4
 line 5
-```
 </attachment>
 
 </attachments>

src/extension/prompts/node/agent/test/__snapshots__/summarization-previousTurnNoRounds-Agent.spec.snap

@@ -69,13 +69,11 @@ copilot_cache_control: { type: 'ephemeral' }
 ~~~md
 <attachments>
 <attachment id="file" filePath="/workspace/file.ts">
-```ts
 line 1
 line 2
 
 line 4
 line 5
-```
 </attachment>
 
 </attachments>

src/extension/prompts/node/panel/fileVariable.tsx

@@ -262,7 +262,7 @@ class CodeSummary extends PromptElement<CodeSummaryProps, unknown> {
 		return (
 			<Tag name='attachment' attrs={attrs} >
 				{this.props.description ? this.props.description + ':\n' : ''}
-				<CodeBlock includeFilepath={this.props.filePathMode === FilePathMode.AsComment} languageId={document.languageId} uri={uri} references={references} code={code} />
+				<CodeBlock includeFilepath={this.props.filePathMode === FilePathMode.AsComment} languageId={document.languageId} uri={uri} references={references} code={code} fence='' />
 			</Tag>
 		);
 	}

src/extension/prompts/node/panel/safeElements.tsx

@@ -67,6 +67,11 @@ export type CodeBlockProps = PromptElementProps<{
 	 * @default true
 	 */
 	readonly shouldTrim?: boolean;
+
+	/**
+	 * Fence style, defaults to '```'. An empty string omits the fence.
+	 */
+	readonly fence?: string;
 }>;
 
 export class CodeBlock extends SafePromptElement<CodeBlockProps> {
@@ -87,7 +92,7 @@ export class CodeBlock extends SafePromptElement<CodeBlockProps> {
 			return this._handleFoulPrompt();
 		}
 		const filePath = this.props.includeFilepath ? this._promptPathRepresentationService.getFilePath(this.props.uri) : undefined;
-		const code = createFencedCodeBlock(this.props.languageId ?? '', this.props.code, this.props.shouldTrim ?? true, filePath);
+		const code = createFencedCodeBlock(this.props.languageId ?? '', this.props.code, this.props.shouldTrim ?? true, filePath, this.props.fence);
 		const reference = this.props.references && <references value={this.props.references} />;
 
 		if (this.props.lineBasedPriority) {

src/extension/prompts/node/panel/test/__snapshots__/fileVariable.spec.ts.snap

@@ -57,7 +57,7 @@ exports[`FileVariable > does include known untitled file 1`] = `
                           {
                             "type": 2,
                             "priority": 9007199254740991,
-                            "text": "\`\`\`python\\ntest!\\n\`\`\`",
+                            "text": "test!",
                             "references": [
                               {
                                 "anchor": {

src/util/common/markdown.ts

@@ -44,15 +44,17 @@ export function createFilepathRegexp(languageId?: string): RegExp {
  * Create a markdown code block with an optional language id and an optional file path.
  * @param filePath The file path to include in the code block. To create the file path use the {@link IPromptPathRepresentationService}
  */
-export function createFencedCodeBlock(languageId: string, code: string, shouldTrim = true, filePath?: string, minNumberOfBackticks = 3): string {
-	const fence = getFenceForCodeBlock(code, minNumberOfBackticks);
+export function createFencedCodeBlock(languageId: string, code: string, shouldTrim = true, filePath?: string, minNumberOfBackticksOrStyle: string | number = 3): string {
+	const fence = typeof minNumberOfBackticksOrStyle === 'number'
+		? getFenceForCodeBlock(code, minNumberOfBackticksOrStyle)
+		: minNumberOfBackticksOrStyle;
 
 	let filepathComment = '';
 	if (filePath) {
 		filepathComment = getFilepathComment(languageId, filePath);
 	}
 
-	return `${fence}${languageIdToMDCodeBlockLang(languageId)}\n${filepathComment}${shouldTrim ? code.trim() : code}\n${fence}`;
+	return `${fence}${fence && (languageIdToMDCodeBlockLang(languageId) + '\n')}${filepathComment}${shouldTrim ? code.trim() : code}${fence && ('\n' + fence)}`;
 }
 
 export function getFilepathComment(languageId: string, filePath: string): string {

test/outcome/-doc-inline.json

@@ -110,7 +110,7 @@
 	{
 		"name": "/doc [inline] [typescript] - supports chat variables",
 		"requests": [
-			"6cedff5109b6ec584c5c8c677d6ab534fbfe771bde11ab4a1f392fcd0d6309cf"
+			"2c7eaaa330d710106d2cacb58b7fcb5e01598d15f75c5f2af08089b543f1b2b1"
 		]
 	}
 ]

test/outcome/-tests-inline.json

@@ -129,7 +129,7 @@
 	{
 		"name": "/tests [inline] [typescript] - supports chat variables",
 		"requests": [
-			"591150e19e6ccfc73da99c993bed686a4992bf1c16ac743cfd963621eb156000"
+			"1c6d4cb42ef1e2b49c136000de18ff4273d4c01297f97850ef4aad0ac1098940"
 		]
 	},
 	{