Fix: Invalid JSON on gc-stats (#1801)

[MitchLewis930]

PR_054

[greptile-apps]

Greptile Overview

Greptile Summary

Fixed invalid JSON generation in the /gc-stats endpoint by replacing manual string concatenation with Ruby's .to_json method.

Key Changes:

• lib/puma/app/status.rb: Added require 'json' and replaced manual JSON construction with GC.stat.to_json
• test/test_cli.rb: Updated test to use JSON.parse instead of regex parsing for the second gc-stats assertion

Issue Fixed:
The old implementation manually constructed JSON strings like "{" + GC.stat.map { |k, v| "\"#{k}\": #{v}" }.join(",") + "}", which produced invalid JSON when GC.stat values were strings (they would be unquoted) or other non-numeric types.

Minor Issue:
The test file update is inconsistent - it only converted the second gc-stats parsing to use JSON.parse (line 199) while leaving the first one (lines 179-185) with the old regex-based approach. Both should use JSON.parse for consistency.

Confidence Score: 4/5

• Safe to merge with minor test inconsistency that should be addressed
• The core fix correctly addresses the invalid JSON issue by using the proper .to_json method. However, the test update is inconsistent (only one of two JSON parsing blocks was updated), which slightly reduces confidence
• test/test_cli.rb should have both gc-stats parsing blocks updated to use JSON.parse for consistency

Important Files Changed

Filename	Overview
lib/puma/app/status.rb	Replaced manual JSON construction with proper to_json method to fix invalid JSON output when GC.stat contains non-numeric values
test/test_cli.rb	Partially updated test to use JSON.parse for the second gc-stats check, but inconsistently left the first check using manual regex parsing

Sequence Diagram

sequenceDiagram
    participant Client
    participant Status as Puma::App::Status
    participant GC as Ruby GC
    participant JSON as JSON Library

    Client->>Status: GET /gc-stats
    Status->>GC: GC.stat
    GC-->>Status: Hash of GC statistics
    Status->>JSON: .to_json
    JSON-->>Status: Valid JSON string
    Status-->>Client: 200 OK with JSON response

    Note over Status,JSON: Old implementation manually<br/>constructed JSON strings,<br/>causing invalid JSON for<br/>non-numeric values

    Note over Status,JSON: New implementation uses<br/>to_json for proper<br/>escaping and formatting

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Additional Comments (1)

test/test_cli.rb
Inconsistent JSON parsing - this first gc-stats check still uses manual regex parsing while the second check (line 199) uses JSON.parse. Both should use JSON.parse for consistency.

    gc_stats = JSON.parse(json_line)
    gc_count_before = gc_stats["count"].to_i

_{Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time!}

Prompt To Fix With AI

This is a comment left during a code review.
Path: test/test_cli.rb
Line: 179:185

Comment:
Inconsistent JSON parsing - this first gc-stats check still uses manual regex parsing while the second check (line 199) uses `JSON.parse`. Both should use `JSON.parse` for consistency.

```suggestion
    gc_stats = JSON.parse(json_line)
    gc_count_before = gc_stats["count"].to_i
```

<sub>Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time!</sub>

How can I resolve this? If you propose a fix, please make it concise.