fix: guard against late chunk after consume teardown

[cesarvspr]

This relates to...

Fixes #5356

Rationale

When a body is consumed (body.json()/text()/etc.) and the stream is then torn down (close/abort/timeout/error), consumeFinish sets consume.body = null but leaves stream[kConsume] in place. If a chunk arrives afterwards — e.g. flushed by a decompress interceptor after teardown — push still routes it to consumePush, which did consume.body.push(chunk) on null and crashed synchronously with:

TypeError: Cannot read properties of null (reading 'push')
    at consumePush (lib/api/readable.js:549)

instead of dropping the late chunk and letting the consume promise reject normally.

The same teardown race is already guarded in two sibling code paths — consumeStart (if (consume.body === null) return) and the 'close' handler (if (this[kConsume].body !== null)). consumePush was simply missing the equivalent guard. This parallels the HTTP/2 teardown guards added in #4880.

Changes

• lib/api/readable.js: add a consume.body === null guard at the top of consumePush so late chunks are dropped instead of crashing.

Features

N/A

Bug Fixes

• Late chunks arriving after consume teardown no longer crash; .json()/.text() reject with UND_ERR_ABORTED as expected.

Breaking Changes and Deprecations

N/A

Status

• I have read and agreed to the Developer's Certificate of Origin
• Tested
• [S] Benchmarked (optional)
• Documented (code comment; no public API change)
• Review ready
• In review
• Merge ready

Test

Added a regression test in test/readable.js (late chunk after consume teardown does not crash). It fails on main with the null-deref and passes with the fix:

not ok 1 - late chunk after consume teardown does not crash   # before fix
        Actual message: "Cannot read properties of null (reading 'push')"

ok  - late chunk after consume teardown does not crash         # after fix

node --test test/readable.js → 10/10 passing; npm run lint clean.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.24%. Comparing base (dd1e50a) to head (70e6d62).
⚠️ Report is 6 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5357   +/-   ##
=======================================
  Coverage   93.23%   93.24%           
=======================================
  Files         110      110           
  Lines       36668    36676    +8     
=======================================
+ Hits        34189    34197    +8     
  Misses       2479     2479           

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[mcollina]

I think the bug is elsewhere. That function should not be called.