procutil: make stream detection in make_line_buffered more correct and strict
In make_line_buffered(), we don’t want to wrap the stream if we know that lines
get flushed to the underlying raw stream already.
Previously, the heuristic was too optimistic. It assumed that any stream which
is not an instance of io.BufferedIOBase doesn’t need wrapping. However, there
are buffered streams that aren’t instances of io.BufferedIOBase, like
Mercurial’s own winstdout.
The new logic is different in two ways:
First, only for the check, if unwraps any combination of WriteAllWrapper and
winstdout.
Second, it skips wrapping the stream only if it is an instance of io.RawIOBase
(or already wrapped). If it is an instance of io.BufferedIOBase, it gets
wrapped. In any other case, the function raises an exception. This ensures
that, if an unknown stream is passed or we add another wrapper in the future,
we don’t wrap the stream if it’s already line buffered or not wrap the stream
if it’s not line buffered. In fact, this was already helpful during development
of this change. Without it, I possibly would have forgot that WriteAllWrapper
needs to be ignored for the check, leading to unnecessary wrapping if stdout is
unbuffered.
The alternative would have been to always wrap unknown streams. However, I
don’t think that anyone would benefit from being less strict. We can expect
streams from the standard library to be subclassing either io.RawIOBase or
io.BufferedIOBase, so running Mercurial in the standard way should not regress
by this change. Py2exe might replace sys.stdout and sys.stderr, but that
currently breaks Mercurial anyway and also these streams don’t claim to be
interactive, so this function is not called for them.
A dummy certificate that will make OS X 10.6+ Python use the system CA
certificate store:
-----BEGIN CERTIFICATE-----
MIIBIzCBzgIJANjmj39sb3FmMA0GCSqGSIb3DQEBBQUAMBkxFzAVBgNVBAMTDmhn
LmV4YW1wbGUuY29tMB4XDTE0MDgzMDA4NDU1OVoXDTE0MDgyOTA4NDU1OVowGTEX
MBUGA1UEAxMOaGcuZXhhbXBsZS5jb20wXDANBgkqhkiG9w0BAQEFAANLADBIAkEA
mh/ZySGlcq0ALNLmA1gZqt61HruywPrRk6WyrLJRgt+X7OP9FFlEfl2tzHfzqvmK
CtSQoPINWOdAJMekBYFgKQIDAQABMA0GCSqGSIb3DQEBBQUAA0EAF9h49LkSqJ6a
IlpogZuUHtihXeKZBsiktVIDlDccYsNy0RSh9XxUfhk+XMLw8jBlYvcltSXdJ7We
aKdQRekuMQ==
-----END CERTIFICATE-----
This certificate was generated to be syntactically valid but never be usable;
it expired before it became valid.
Created as:
$ cat > cn.conf << EOT
> [req]
> distinguished_name = req_distinguished_name
> [req_distinguished_name]
> commonName = Common Name
> commonName_default = no.example.com
> EOT
$ openssl req -nodes -new -x509 -keyout /dev/null \
> -out dummycert.pem -days -1 -config cn.conf -subj '/CN=hg.example.com'
To verify the content of this certificate:
$ openssl x509 -in dummycert.pem -noout -text
Certificate:
Data:
Version: 1 (0x0)
Serial Number: 15629337334278746470 (0xd8e68f7f6c6f7166)
Signature Algorithm: sha1WithRSAEncryption
Issuer: CN=hg.example.com
Validity
Not Before: Aug 30 08:45:59 2014 GMT
Not After : Aug 29 08:45:59 2014 GMT
Subject: CN=hg.example.com
Subject Public Key Info:
Public Key Algorithm: rsaEncryption
Public-Key: (512 bit)
Modulus:
00:9a:1f:d9:c9:21:a5:72:ad:00:2c:d2:e6:03:58:
19:aa:de:b5:1e:bb:b2:c0:fa:d1:93:a5:b2:ac:b2:
51:82:df:97:ec:e3:fd:14:59:44:7e:5d:ad:cc:77:
f3:aa:f9:8a:0a:d4:90:a0:f2:0d:58:e7:40:24:c7:
a4:05:81:60:29
Exponent: 65537 (0x10001)
Signature Algorithm: sha1WithRSAEncryption
17:d8:78:f4:b9:12:a8:9e:9a:22:5a:68:81:9b:94:1e:d8:a1:
5d:e2:99:06:c8:a4:b5:52:03:94:37:1c:62:c3:72:d1:14:a1:
f5:7c:54:7e:19:3e:5c:c2:f0:f2:30:65:62:f7:25:b5:25:dd:
27:b5:9e:68:a7:50:45:e9:2e:31