report error on unexpected EOF for fixed length HTTP body

[Guest0x0]

Previously, the HTTP body parser does not perform length validation for fixed length body (i.e. Content-Length), this will result in unexpected EOF from the transport layer not being reported as error. This PR fixes the issue. The HTTP body will now raise @io.ReaderClosed on unexpected EOF for fixed length body.

The fix reveal another bug in previous code base. For HEAD request, the response body is always empty, but Content-Length etc. can still be set to indicate what the client would get if a GET request is made. So for response to HEAD request, we should ignore Content-Length etc., but this logic was not implemented previously. Due to the lack of length validation, test for this behavior accidentally passed. This PR also fixes this problem: the response body to a HEAD request is now always assumed to be empty, no matter what headers are set.

[coveralls]

Coverage Report for CI Build 502

Coverage increased (+0.04%) to 77.566%

Details

• Coverage increased (+0.04%) from the base build.
• Patch coverage: 3 of 3 lines across 1 file are fully covered (100%).
• 1 coverage regression across 1 file.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

1 previously-covered line in 1 file lost coverage.

File	Lines Losing Coverage	Coverage
src/internal/event_loop/network.mbt	1	86.36%

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Coverage Stats

Relevant Lines:	4676
Covered Lines:	3627
Line Coverage:	77.57%
Coverage Strength:	72158.55 hits per line

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💛 - Coveralls