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double curly brace can have incorrect syntax highlighting inside format within expression

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Assessment

Difficulty
3/5
Estimated time
1-2 days
Newbie friendliness
45/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Stale
Tech stack
typescript
Domain
tooling

Research direction

Start by reproducing the workflow in the VS Code editor and inspect how the extension highlights nested GitHub Actions expressions and format strings. Trace the syntax-highlighting entry point for expression parsing, then verify that the escaped double closing brace is not treated as the expression end while the final closing brace remains highlighted.

Written by the indexing model from the issue text.

Description

bug

Describe the bug
When a double closing curly brace (}} is used as an escape to represent a single closing curly brace (}) inside a format function that is within an expression, it gets incorrectly colored as the end of the expression.

To Reproduce
Steps to reproduce the behavior:

  1. With the workflow file below, open in vscode editor
  2. View the syntax highlighting as incorrect. The first double closing curly brace on line 19 should not be yellow.
name: Double Curly Brace Workflow

on:
  workflow_dispatch:
    inputs:
      something-to-print:
        description: Something to print in powershell.
        required: true
        type: string

jobs:
  double_curly_brace_job:
    runs-on:
      labels: windows

    steps:
    - name: Double Curly Brace Step
      env:
        VAR_WITH_DOUBLE_CURLY_BRACE: "${{ format('{{ {0} }}', inputs.something-to-print) }}"
      run: |
        echo "${{ env.VAR_WITH_DOUBLE_CURLY_BRACE }}"

Expected behavior
The last double closing curly brace should be yellow on line 19.

Screenshots
image

Extension Version
v0.26.5

Additional context
I am testing this on Mac OS Sonoma 14.5
code --version 1.91.1 f1e16e1e6214d7c44d078b1f0607b2388f29d729 x64

Dominant language
TypeScript
Stars
661
Forks
214
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