fix(workflow): handle }} inside strings in expression parser

[majiayu000]

Summary

• Fixes expression parser incorrectly identifying }} inside quoted strings as expression closing marker
• Adds string context tracking (single quotes, double quotes, backticks)
• Properly handles escape sequences inside strings

Test plan

• Added comprehensive unit tests for splitExpression and joinExpression
• Tests cover JMESPath expressions with nested braces
• Tests cover all quote types (single, double, backtick)
• Tests cover escaped quotes inside strings
• All existing expression tests pass
• TypeScript checks pass

Example

Before this fix, the expression:

{{ $jmespath($json, '{reviewers: values[*].{uuid: user.uuid}}') }}

Would fail with "invalid syntax" because }} inside the JMESPath string was interpreted as the expression end marker.

After this fix, the expression is correctly parsed and executed.

Fixes #22264

[cubic-dev-ai]

1 issue found across 2 files

Prompt for AI agents (all issues)

Check if these issues are valid — if so, understand the root cause of each and fix them.


<file name="packages/workflow/src/extensions/expression-parser.ts">

<violation number="1" location="packages/workflow/src/extensions/expression-parser.ts:38">
P1: Escape handling doesn&#39;t account for consecutive backslashes (`\\`). When `\\` appears before a quote, the quote should close the string (since the first `\` escapes the second `\`, not the quote). The current logic incorrectly skips the quote because it only checks if `prevChar === &#39;\\&#39;` without tracking whether that backslash was itself escaped.

Consider tracking escape state instead of just checking the previous character:</violation>
</file>

_{Reply to cubic to teach it or ask questions. Re-run a review with @cubic-dev-ai review this PR}

[cubic-dev-ai]

P1: Escape handling doesn't account for consecutive backslashes (\\). When \\ appears before a quote, the quote should close the string (since the first \ escapes the second \, not the quote). The current logic incorrectly skips the quote because it only checks if prevChar === '\\' without tracking whether that backslash was itself escaped.

Consider tracking escape state instead of just checking the previous character:

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At packages/workflow/src/extensions/expression-parser.ts, line 38:

<comment>Escape handling doesn&#39;t account for consecutive backslashes (`\\`). When `\\` appears before a quote, the quote should close the string (since the first `\` escapes the second `\`, not the quote). The current logic incorrectly skips the quote because it only checks if `prevChar === &#39;\\&#39;` without tracking whether that backslash was itself escaped.

Consider tracking escape state instead of just checking the previous character:</comment>

<file context>
@@ -21,6 +21,36 @@ export const escapeCode = (text: string): string =&gt; {
+		const prevChar = i &gt; 0 ? text[i - 1] : &#39;&#39;;
+
+		// Skip escaped characters
+		if (prevChar === &#39;\\&#39;) {
+			continue;
+		}
</file context>