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 parents command
$ hg init repo
$ cd repo
no working directory
$ hg parents
$ echo a > a
$ echo b > b
$ hg ci -Amab -d '0 0'
adding a
adding b
$ echo a >> a
$ hg ci -Ama -d '1 0'
$ echo b >> b
$ hg ci -Amb -d '2 0'
$ echo c > c
$ hg ci -Amc -d '3 0'
adding c
$ hg up -C 1
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ echo d > c
$ hg ci -Amc2 -d '4 0'
adding c
created new head
$ hg up -C 3
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg parents
changeset: 3:02d851b7e549
user: test
date: Thu Jan 01 00:00:03 1970 +0000
summary: c
$ hg parents a
changeset: 1:d786049f033a
user: test
date: Thu Jan 01 00:00:01 1970 +0000
summary: a
hg parents c, single revision
$ hg parents c
changeset: 3:02d851b7e549
user: test
date: Thu Jan 01 00:00:03 1970 +0000
summary: c
$ hg parents -r 3 c
abort: 'c' not found in manifest
[10]
$ hg parents -r 2
changeset: 1:d786049f033a
user: test
date: Thu Jan 01 00:00:01 1970 +0000
summary: a
$ hg parents -r 2 a
changeset: 1:d786049f033a
user: test
date: Thu Jan 01 00:00:01 1970 +0000
summary: a
$ hg parents -r 2 ../a
abort: ../a not under root '$TESTTMP/repo'
[255]
cd dir; hg parents -r 2 ../a
$ mkdir dir
$ cd dir
$ hg parents -r 2 ../a
changeset: 1:d786049f033a
user: test
date: Thu Jan 01 00:00:01 1970 +0000
summary: a
$ hg parents -r 2 path:a
changeset: 1:d786049f033a
user: test
date: Thu Jan 01 00:00:01 1970 +0000
summary: a
$ cd ..
$ hg parents -r 2 glob:a
abort: can only specify an explicit filename
[10]
merge working dir with 2 parents, hg parents c
$ HGMERGE=true hg merge
merging c
0 files updated, 1 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg parents c
changeset: 3:02d851b7e549
user: test
date: Thu Jan 01 00:00:03 1970 +0000
summary: c
changeset: 4:48cee28d4b4e
tag: tip
parent: 1:d786049f033a
user: test
date: Thu Jan 01 00:00:04 1970 +0000
summary: c2
merge working dir with 1 parent, hg parents
$ hg up -C 2
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ HGMERGE=true hg merge -r 4
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg parents
changeset: 2:6cfac479f009
user: test
date: Thu Jan 01 00:00:02 1970 +0000
summary: b
changeset: 4:48cee28d4b4e
tag: tip
parent: 1:d786049f033a
user: test
date: Thu Jan 01 00:00:04 1970 +0000
summary: c2
merge working dir with 1 parent, hg parents c
$ hg parents c
changeset: 4:48cee28d4b4e
tag: tip
parent: 1:d786049f033a
user: test
date: Thu Jan 01 00:00:04 1970 +0000
summary: c2
$ cd ..