BUG with POSTing more than 8 KiO data with recent versions of WGET

[Taylor]

To   : bug-wget@gnu.org
Subj : BUG with POSTing more than 8 KiO data with recent versions of WGET

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There is (most likely) a severe bug in recent versions of WGET,
including 1.19.4 and 1.21.1, but not in good old 1.11.4 from
year 2008.

Expected behaviour: POSTing will work irrespective size of the postdata

Observed behaviour: POSTing fails with exit code 4 if size of the
                    postdata exceeds ca 8 KiO

With WGET 1.11.4 I could POST data irrespective size, only
percent-encoding tested at that time.

With CURL I can POST data irrespective size, both percent-encoded
and multipart-encoded.

With WGET 1.19.4 and 1.21.1 I can post data of limited size, both
percent-encoded and multipart-encoded.

With WGET 1.19.4 and 1.21.1 posting reliably fails if size of the
postdata exceeds ca 8 KiO.

I do the encoding myself and run WGET and CURL in a pretty raw way,
not caring about the fact that CURL can multipart-encode whereas
WGET can't.

Using the Win32 versions of WGET, Linux not installed.

Result from "--debug" success (exitcode is 0 and data arrives
at the server):

> ---request end---
> [writing BODY file YPOST.TMP ... done]
> HTTP request sent, awaiting response... seconds 60.00, Winsock error: 0
> seconds 60.00, Winsock error: 0
> seconds 60.00, Winsock error: 0

> ---response begin---
> HTTP/1.1 200 OK

Result from "--debug" failure (exitcode is 4 after 3 attempts
and data does not arrive at the server):

> ---request end---
> [writing BODY file YPOST.TMP ... Closed 4/SSL 0x009fb810
> Giving up.

> Saving cookies to YCOOK.TMP.
> Done saving cookies.

The report is not very verbose, "Closed" is the only hint about the
problem. The file YPOST.TMP contains the postdata and is good in
both cases, but bigger in the lower one.

Of course I can use CURL instead of WGET, but it's good to have
options, and bad to have bugs, given that this probably is a bug
of WGET. I am aware that CURL is more intended for posting than WGET,
but this used to work with old versions (1.11.4) before they got
unusable due to 3rd party hard cryptographic deprecation.