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.
Test that the syntax of "unified tests" is properly processed
==============================================================
Simple commands:
$ echo foo
foo
$ printf 'oh no'
oh no (no-eol)
$ printf 'bar\nbaz\n' | cat
bar
baz
Multi-line command:
$ foo() {
> echo bar
> }
$ foo
bar
Return codes before inline python:
$ sh -c 'exit 1'
[1]
Doctest commands:
>>> print('foo')
foo
$ echo interleaved
interleaved
>>> for c in 'xyz':
... print(c)
x
y
z
>>> print()
>>> foo = 'global name'
>>> def func():
... print(foo, 'should be visible in func()')
>>> func()
global name should be visible in func()
>>> print('''multiline
... string''')
multiline
string
Regular expressions:
$ echo foobarbaz
foobar.* (re)
$ echo barbazquux
.*quux.* (re)
Globs:
$ printf '* \\foobarbaz {10}\n'
\* \\fo?bar* {10} (glob)
Literal match ending in " (re)":
$ echo 'foo (re)'
foo (re)
Windows: \r\n is handled like \n and can be escaped:
#if windows
$ printf 'crlf\r\ncr\r\tcrlf\r\ncrlf\r\n'
crlf
cr\r (no-eol) (esc)
\tcrlf (esc)
crlf\r (esc)
#endif
Escapes:
$ "$PYTHON" -c 'from mercurial.utils.procutil import stdout; stdout.write(b"\xff")'
\xff (no-eol) (esc)
Escapes with conditions:
$ "$PYTHON" -c 'from mercurial.utils.procutil import stdout; stdout.write(b"\xff")'
\xff (no-eol) (esc) (true !)
Combining esc with other markups - and handling lines ending with \r instead of \n:
$ printf 'foo/bar\r'
fo?/bar\r (no-eol) (glob) (esc)
#if windows
$ printf 'foo\\bar\r'
foo/bar\r (no-eol) (esc)
#endif
$ printf 'foo/bar\rfoo/bar\r'
foo.bar\r [(]no-eol[)] (re) (esc)
foo.bar\r \(no-eol\) (re)
testing hghave
$ hghave true
$ hghave false
skipped: missing feature: nail clipper
[1]
$ hghave no-true
skipped: system supports yak shaving
[1]
$ hghave no-false
Conditional sections based on hghave:
#if true
$ echo tested
tested
#else
$ echo skipped
#endif
#if false
$ echo skipped
#else
$ echo tested
tested
#endif
#if no-false
$ echo tested
tested
#else
$ echo skipped
#endif
#if no-true
$ echo skipped
#else
$ echo tested
tested
#endif
Exit code:
$ (exit 1)
[1]