feat(debug-proxy-errors-plugin): diagnostic message for POST + bodyParser + ECONNRESET error

[chimurai]

resolves: #40

Add debug message to help developer fix ECONNRESET error when POST requests with a bodyParser middleware are used.

Summary by CodeRabbit

Summary by CodeRabbit

• Bug Fixes

  • Improved proxy error handling when the request body was already parsed and the upstream connection resets.
  • Enhanced console error output for the specific POST + ECONNRESET case.

• Tests

  • Added end-to-end coverage to verify the proxy returns 504 and emits a single console error containing the [ERR_HPM.GH40] identifier.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 9dc117c4-d955-4afc-ae3c-e826969bda14

📥 Commits

Reviewing files that changed from the base of the PR and between bfa9fbd and aaaf09c.

📒 Files selected for processing (2)

• src/plugins/default/debug-proxy-errors-plugin.ts
• test/e2e/http-proxy-middleware.spec.ts

🚧 Files skipped from review as they are similar to previous changes (2)

• src/plugins/default/debug-proxy-errors-plugin.ts
• test/e2e/http-proxy-middleware.spec.ts

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📝 Walkthrough

Walkthrough

Adds a styled debug log for ECONNRESET errors when a POST request already has a parsed body, and adds an end-to-end test covering the reset case and expected 504 response.

Changes

Body-parser proxy reset logging

Layer / File(s)	Summary
Error logging check src/plugins/default/debug-proxy-errors-plugin.ts	Imports styleText, adds a body-parser guidance message, and logs it on ECONNRESET for POST requests with an existing req.body.
E2E reset test test/e2e/http-proxy-middleware.spec.ts	Sets up bodyParser.json(), simulates an upstream reset on POST /api, checks for 504, and verifies one [ERR_HPM.GH40] console error.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Possibly related PRs

• chimurai/http-proxy-middleware#1272: Also adds end-to-end coverage around proxy error logging and asserts specific console error output.

Poem

🐰 I twitched my nose at proxy rain,
and found a reset in the chain.
A crimson note now helps me see,
why POST got lost by ECONNRESET sea.
Hop-hop—504 is finally tame!

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly describes the new diagnostic message for POST requests affected by bodyParser and ECONNRESET.
Linked Issues check	✅ Passed	The change addresses issue #40 by detecting parsed POST bodies on ECONNRESET and emitting actionable guidance.
Out of Scope Changes check	✅ Passed	The patch stays focused on the proxy error diagnostic and its matching E2E coverage, with no unrelated changes.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch debug-message-bodyparser-econnreset

---

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[pkg-pr-new]

npm i https://pkg.pr.new/http-proxy-middleware@1273

commit: aaaf09c

[coveralls]

coverage: 95.227% (+0.04%) from 95.183% — debug-message-bodyparser-econnreset into master

[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@src/plugins/default/debug-proxy-errors-plugin.ts`:
- Around line 33-36: The GH40 body-parser check in debug-proxy-errors-plugin is
too loose because it only tests for the presence of req.body, so unrelated
ECONNRESET errors can still trigger the guidance. Tighten the predicate in the
request/error handling block around BODY_PARSER_ERROR_MESSAGE to require an
actually populated parsed body (for example, a non-empty object/array or other
real content) before logging, while keeping the existing req.method === 'POST'
and ECONNRESET conditions in place.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 84a23401-86b2-40f4-b5d0-df49a0ef5666

📥 Commits

Reviewing files that changed from the base of the PR and between 006f1a4 and 384cdb4.

📒 Files selected for processing (2)

• src/plugins/default/debug-proxy-errors-plugin.ts
• test/e2e/http-proxy-middleware.spec.ts