Show the request body in the failure dump

[korya]

Problem

After a failed POST the dump left out the one thing you need: what was sent.

FAILED: POST http://…/echo (HTTP/1.1)

POST /echo HTTP/1.1
Host: 127.0.0.1:8791
User-Agent: Go-http-client/1.1
Content-Length: 24          ← claims 24 bytes
                            ← ships zero

Two problems in one. The payload is missing when it is the first question anyone asks, and what is printed is not a valid HTTP message — it cannot be replayed, pasted into a bug report, or fed to anything that parses HTTP.

The cause is ordering: the request is rendered after it has been sent, and sending consumes req.Body.

Solution

Clone the request through GetBody before rendering it, and stop using http.Request.Write as a pretty-printer.

POST /echo HTTP/1.1
Host: 127.0.0.1:59095
User-Agent: Go-http-client/1.1
Content-Length: 24

THIS-IS-THE-REQUEST-BODY

The replay machinery already existed — --retry needed a fresh request per attempt, so cloneForAttempt was already there and already tested. This is a second caller for it.

Why not just re-attach the body and let Write do it

That fixes the missing payload and reintroduces #18. http.Request.Write is a wire-format serializer: a 5MB -d would land in the report whole, and a binary one would go to the terminal raw. writeTo stopped using http.Response.Write for exactly that reason, and the request half never got the same treatment.

So the split is: headers from Write, which knows what actually goes on the wire — Host, User-Agent and Content-Length are none of them in req.Header, so hand-rendering would silently lose the very header this issue is about — and the body through the same renderer as the response.

Content-Length: 300

01234567890123456789…                          ← 256 bytes

  << Payload is cropped: 44 bytes are hidden >>

Content-Length: 4

00000000  ff fe 07 08                    |....|

A request with no body renders exactly as before. A body that cannot be replayed — no GetBody — falls back to headers alone rather than failing, because a broken dump must not replace the failure being reported.

Other Changes

TestKnownIssue19RequestBodyMissing is deleted, replaced by TestE2EDumpShowsTheRequestBody: the payload appears, it survives a --retry (the dump records one exchange, so it must outlast however many attempts it took), long payloads crop, binary payloads hex-dump, and a body-less GET is untouched.

Test_writeRequest covers the same five at the unit level against a request drained the way http.Client drains it, so the state under test is the state the dump actually receives rather than a fresh request that would pass trivially.

Note on binary payloads: a NUL byte cannot reach -d at all, since exec rejects it in an argument. The tests use \xff\xfe\x07\x08, which is reachable and equally non-printable.

There are no screenshots because there is no rendered UI; this tool's user-visible surface is terminal output, shown inline above.

Closes #19

Related:

• Reject a -H value with no colon #81 — merged; this PR was rebased off it onto master
• Failure dump truncates or destroys the response body (Content-Length is not updated) #18 — the response half of the same lesson, fixed earlier

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