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.
$ hg init repo
$ cd repo
$ for n in 0 1 2 3 4 5 6 7 8 9 10 11; do
> echo $n > $n
> hg ci -qAm $n
> done
test revset support
$ cat <<'EOF' >> .hg/hgrc
> [extdata]
> filedata = file:extdata.txt
> notes = notes.txt
> shelldata = shell:cat extdata.txt | grep 2
> emptygrep = shell:cat extdata.txt | grep empty
> badparse = shell:cat badparse.txt
> EOF
$ cat <<'EOF' > extdata.txt
> 2 another comment on 2
> 3
> EOF
$ cat <<'EOF' > notes.txt
> f6ed this change is great!
> e834 this is buggy :(
> 0625 first post
> bogusnode gives no error
> a ambiguous node gives no error
> EOF
$ hg log -qr "extdata(filedata)"
2:f6ed99a58333
3:9de260b1e88e
$ hg log -qr "extdata(shelldata)"
2:f6ed99a58333
test weight of extdata() revset
$ hg debugrevspec -p optimized "extdata(filedata) & 3"
* optimized:
(andsmally
(func
(symbol 'extdata')
(symbol 'filedata'))
(symbol '3'))
3
test non-zero exit of shell command
$ hg log -qr "extdata(emptygrep)"
abort: extdata command 'cat extdata.txt | grep empty' failed: exited with status 1
[255]
test bad extdata() revset source
$ hg log -qr "extdata()"
hg: parse error: extdata takes at least 1 string argument
[10]
$ hg log -qr "extdata(unknown)"
abort: unknown extdata source 'unknown'
[255]
test a zero-exiting source that emits garbage to confuse the revset parser
$ cat > badparse.txt <<'EOF'
> +---------------------------------------+
> 9de260b1e88e
> EOF
It might be nice if this error message mentioned where the bad string
came from (eg line X of extdata source S), but the important thing is
that we don't crash before we can print the parse error.
$ hg log -qr "extdata(badparse)"
hg: parse error at 0: not a prefix: +
(+---------------------------------------+
^ here)
[10]
test template support:
$ hg log -r:3 -T "{node|short}{if(extdata('notes'), ' # {extdata('notes')}')}\n"
06254b906311 # first post
e8342c9a2ed1 # this is buggy :(
f6ed99a58333 # this change is great!
9de260b1e88e
test template cache:
$ hg log -r:3 -T '{rev} "{extdata("notes")}" "{extdata("shelldata")}"\n'
0 "first post" ""
1 "this is buggy :(" ""
2 "this change is great!" "another comment on 2"
3 "" ""
test bad extdata() template source
$ hg log -T "{extdata()}\n"
hg: parse error: extdata expects one argument
[10]
$ hg log -T "{extdata('unknown')}\n"
abort: unknown extdata source 'unknown'
[255]
$ hg log -T "{extdata(unknown)}\n"
hg: parse error: empty data source specified
(did you mean extdata('unknown')?)
[10]
$ hg log -T "{extdata('{unknown}')}\n"
hg: parse error: empty data source specified
[10]
we don't fix up relative file URLs, but we do run shell commands in repo root
$ mkdir sub
$ cd sub
$ hg log -qr "extdata(filedata)"
abort: error: $ENOENT$
[100]
$ hg log -qr "extdata(shelldata)"
2:f6ed99a58333
$ cd ..