worker: avoid potential partial write of pickled data
Previously, the code wrote the pickled data using os.write(). However,
os.write() can write less bytes than passed to it. To trigger the problem, the
pickled data had to be larger than
2147479552 bytes on my system.
Instead, open a file object and pass it to pickle.dump(). This also has the
advantage that it doesn’t buffer the whole pickled data in memory.
Note that the opened file must be buffered because pickle doesn’t support
unbuffered streams because unbuffered streams’ write() method might write less
bytes than passed to it (like os.write()) but pickle.dump() relies on that all
bytes are written (see https://github.com/python/cpython/issues/93050).
The side effect of using a file object and a with statement is that wfd is
explicitly closed now while it seems like before it was implicitly closed by
process exit.
This tests if hgweb and hgwebdir still work if the REQUEST_URI variable is
no longer passed with the request. Instead, SCRIPT_NAME and PATH_INFO
should be used from d74fc8dec2b4 onward to route the request.
$ hg init repo
$ cd repo
$ echo foo > bar
$ hg add bar
$ hg commit -m "test"
$ hg tip
changeset: 0:61c9426e69fe
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: test
$ cat > request.py <<EOF
> import os
> import sys
> from mercurial import (
> hgweb,
> util,
> )
> stringio = util.stringio
>
> errors = stringio()
> input = stringio()
>
> def startrsp(status, headers):
> print('---- STATUS')
> print(status)
> print('---- HEADERS')
> print([i for i in headers if i[0] != 'ETag'])
> print('---- DATA')
> sys.stdout.flush()
> return output.write
>
> env = {
> 'wsgi.version': (1, 0),
> 'wsgi.url_scheme': 'http',
> 'wsgi.errors': errors,
> 'wsgi.input': input,
> 'wsgi.multithread': False,
> 'wsgi.multiprocess': False,
> 'wsgi.run_once': False,
> 'REQUEST_METHOD': 'GET',
> 'PATH_INFO': '/',
> 'SCRIPT_NAME': '',
> 'SERVER_NAME': '$LOCALIP',
> 'SERVER_PORT': os.environ['HGPORT'],
> 'SERVER_PROTOCOL': 'HTTP/1.0'
> }
>
> def process(app):
> try:
> stdout = sys.stdout.buffer
> except AttributeError:
> stdout = sys.stdout
> content = app(env, startrsp)
> stdout.write(output.getvalue())
> stdout.write(b''.join(content))
> stdout.flush()
> getattr(content, 'close', lambda : None)()
> if errors.getvalue():
> print('---- ERRORS')
> print(errors.getvalue())
> sys.stdout.flush()
>
> output = stringio()
> env['QUERY_STRING'] = 'style=atom'
> process(hgweb.hgweb(b'.', name=b'repo'))
>
> output = stringio()
> env['QUERY_STRING'] = 'style=raw'
> process(hgweb.hgwebdir({b'repo': b'.'}))
> EOF
$ "$PYTHON" request.py
---- STATUS
200 Script output follows
---- HEADERS
[('Content-Type', 'application/atom+xml; charset=ascii')]
---- DATA
<?xml version="1.0" encoding="ascii"?>
<feed xmlns="http://www.w3.org/2005/Atom">
<!-- Changelog -->
<id>http://$LOCALIP:$HGPORT/</id> (glob)
<link rel="self" href="http://$LOCALIP:$HGPORT/atom-log"/> (glob)
<link rel="alternate" href="http://$LOCALIP:$HGPORT/"/> (glob)
<title>repo Changelog</title>
<updated>1970-01-01T00:00:00+00:00</updated>
<entry>
<title>[default] test</title>
<id>http://$LOCALIP:$HGPORT/#changeset-61c9426e69fef294feed5e2bbfc97d39944a5b1c</id> (glob)
<link href="http://$LOCALIP:$HGPORT/rev/61c9426e69fe"/> (glob)
<author>
<name>test</name>
<email>test</email>
</author>
<updated>1970-01-01T00:00:00+00:00</updated>
<published>1970-01-01T00:00:00+00:00</published>
<content type="xhtml">
<table xmlns="http://www.w3.org/1999/xhtml">
<tr>
<th style="text-align:left;">changeset</th>
<td>61c9426e69fe</td>
</tr>
<tr>
<th style="text-align:left;">branch</th>
<td>default</td>
</tr>
<tr>
<th style="text-align:left;">bookmark</th>
<td></td>
</tr>
<tr>
<th style="text-align:left;">tag</th>
<td>tip</td>
</tr>
<tr>
<th style="text-align:left;">user</th>
<td>test</td>
</tr>
<tr>
<th style="text-align:left;vertical-align:top;">description</th>
<td>test</td>
</tr>
<tr>
<th style="text-align:left;vertical-align:top;">files</th>
<td>bar<br /></td>
</tr>
</table>
</content>
</entry>
</feed>
---- STATUS
200 Script output follows
---- HEADERS
[('Content-Type', 'text/plain; charset=ascii')]
---- DATA
/repo/
$ cd ..