Fix environment variable placeholder format in prompt rendering

[Copilot]

Fix Environment Variable Placeholder Format in Prompt Rendering

Issue: Environment variable placeholders in prompt text were not being replaced at runtime, resulting in literal placeholders appearing in the final prompt instead of actual values.

Root Cause:

• expression_extraction.go: Created placeholders as __VAR__ format
• interpolate_prompt.cjs: Expected different format for variable interpolation AND was filtering variables incorrectly
• Format mismatch and incorrect variable filtering prevented variable interpolation from working

Changes Made:

• Changed placeholder format to @@VAR@@ to avoid interfering with bash heredoc variable expansion syntax
• Updated expression_extraction.go to use @@VAR@@ format
• Updated interpolate_prompt.cjs to recognize and replace @@VAR@@ placeholders
• Fixed interpolate_prompt.cjs to include all GH_AW_ prefixed variables (not just GH_AW_EXPR_) - the compiler generates both GH_AW_GITHUB_ACTOR for simple expressions and GH_AW_EXPR_12345678 for complex expressions
• Added unresolved placeholder detection in print_prompt_summary.sh - warns about any @@VAR@@ placeholders that weren't replaced, helping catch interpolation issues early
• Updated template.go to recognize @@ prefix and skip wrapping
• Updated test files to expect new @@VAR@@ format:
  • expression_extraction_test.go
  • template_rendering_test.go
  • template_expression_integration_test.go
  • interpolate_prompt.test.cjs
• All expression extraction and interpolation tests pass
• Code formatted with make fmt
• Merged main branch (resolved conflicts in campaign-generator.lock.yml)
• Recompiled all workflows with make recompile (126 workflows compiled successfully)

Key Fix:
The interpolate_prompt.cjs script was only looking for environment variables starting with GH_AW_EXPR_, but the compiler generates two types of variable names:

1. Simple expressions (e.g., github.actor) → GH_AW_GITHUB_ACTOR (no EXPR_ prefix)
2. Complex expressions (e.g., expressions with operators) → GH_AW_EXPR_12345678 (with EXPR_ prefix and hash)

The fix now includes all GH_AW_ prefixed variables (excluding GH_AW_PROMPT), ensuring both simple and complex expressions are properly interpolated.

Example Output:

# Environment variable definition
GH_AW_GITHUB_EVENT_ISSUE_NUMBER: ${{ github.event.issue.number }}

# Placeholder in heredoc (safe from bash expansion)
cat << 'PROMPT_EOF' >> "$GH_AW_PROMPT"
{{#if @@GH_AW_GITHUB_EVENT_ISSUE_NUMBER@@ }}
- **issue-number**: #@@GH_AW_GITHUB_EVENT_ISSUE_NUMBER@@
{{/if}}
PROMPT_EOF

Warning Detection:
The print prompt step now checks for unresolved placeholders and reports them as warnings:

::warning::Unresolved placeholders found in prompt:
::warning::  - @@GH_AW_SOME_VARIABLE@@

The @@VAR@@ format:

• Does not interfere with bash heredoc variable expansion (${VAR})
• Is visually distinct and commonly used for placeholders
• Works correctly with single-quoted heredoc delimiters
• Enables proper runtime interpolation by interpolate_prompt.cjs

Original prompt

Reference: https://github.com/githubnext/gh-aw/actions/runs/21093306445/job/60667503208#step:22:1

The step that renders the prompt is not properly formatting the environment variable entries and as a result they are not replaced. See this generated prompt:

• issue-number: #GH_AW_GITHUB_EVENT_ISSUE_NUMBER

It should have been the issue number value. Fix compiler, add tests.

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Changeset

• Type: patch
• Description: Auto-generated changeset added to record this PR as a patch-level change.

Ahoy! This treasure was crafted by 🏴‍☠️ Changeset Generator

[pelikhan]

@copilot use variable format that does not interfere with heredoc

[Copilot]

@copilot use variable format that does not interfere with heredoc

Changed placeholder format from ${VAR} to @@VAR@@ to avoid any potential interference with bash heredoc variable expansion syntax. The @@ format is visually distinct, commonly used for placeholders, and works correctly within single-quoted heredoc delimiters. Commit: 9939e6d

[pelikhan]

@copilot merge main and recompile

[Copilot]

@copilot merge main and recompile

Merged main branch and recompiled all workflows. Resolved merge conflict in campaign-generator.lock.yml. Successfully compiled 127 workflows with the @@var@@ placeholder format. Commit: 26c4280

[github-actions]

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[github-actions]

📰 VERDICT: Smoke Copilot has concluded. All systems operational. This is a developing story. 🎤

[github-actions]

🎬 THE END — Smoke Claude MISSION: ACCOMPLISHED! The hero saves the day! ✨

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✨ The prophecy is fulfilled... Smoke Codex has completed its mystical journey. The stars align. 🌟

[github-actions]

Smoke Test Results (Claude Engine)

Last 2 merged PRs: ❌ (GitHub API placeholder issue)
Serena Go: ❌ (Go not available)
Playwright: ✅ (Navigated to GitHub, verified title)
Tavily Web Search: ✅ (5 results for "GitHub Agentic Workflows")
File Writing: ✅ (Created test file)
Bash Tool: ✅ (Verified file contents)

Overall Status: FAIL (2/6 tests passed)

AI generated by Smoke Claude

[github-actions]

Smoke Test Results for Copilot Engine

Last 2 Merged PRs:

• Consolidate campaign generation prompts and improve messaging #10460: Consolidate campaign generation prompts and improve messaging
• Add required scope fields (allowed-repos/allowed-orgs) to campaign specs #10456: Add required scope fields to campaign specs

Test Results:

• ✅ GitHub MCP - Retrieved last 2 merged PRs
• ❌ Serena Go - go command not available
• ✅ Playwright - Navigated to github.com, title contains "GitHub"
• ✅ File Writing - Created test file successfully
• ✅ Bash Tool - Verified file creation

Overall Status: FAIL (1/5 tests failed)

AI generated by Smoke Copilot

[pelikhan]

@copilot the substitution did not work see the final prompt from this run:

Reference: https://github.com/githubnext/gh-aw/actions/runs/21095670266/job/60672836421#step:24:1

Add check in print prompt to search for unresolved expression and report them as warnings.

[Copilot]

@copilot the substitution did not work see the final prompt from this run:

Reference: https://github.com/githubnext/gh-aw/actions/runs/21095670266/job/60672836421#step:24:1...

Fixed the interpolation issue - interpolate_prompt.cjs was only looking for GH_AW_EXPR_* variables but the compiler generates GH_AW_* variables for simple expressions (e.g., GH_AW_GITHUB_ACTOR). Now includes all GH_AW_ prefixed variables.

Also added warning detection in print_prompt_summary.sh that checks for unresolved @@VAR@@ placeholders and reports them as warnings. This will help catch any future interpolation issues.

Commit: 4fde3a7