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.
# init
$ hg init
$ echo a > a
$ hg add a
$ hg commit -m'a'
$ echo b > b
$ hg add b
$ hg commit -m'b'
$ hg up -C 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ echo c > c
$ hg add c
$ hg commit -m'c'
created new head
# test merging of diverged bookmarks
$ hg bookmark -r 1 "c@diverge"
$ hg bookmark -r 1 b
$ hg bookmark c
$ hg bookmarks
b 1:d2ae7f538514
* c 2:d36c0562f908
c@diverge 1:d2ae7f538514
$ hg merge "c@diverge"
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg commit -m'merge'
$ hg bookmarks
b 1:d2ae7f538514
* c 3:b8f96cf4688b
$ hg up -C 3
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
(leaving bookmark c)
$ echo d > d
$ hg add d
$ hg commit -m'd'
$ hg up -C 3
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ echo e > e
$ hg add e
$ hg commit -m'e'
created new head
$ hg up -C 5
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg bookmark e
$ hg bookmarks
b 1:d2ae7f538514
c 3:b8f96cf4688b
* e 5:26bee9c5bcf3
# the picked side is bookmarked
$ hg up -C 4
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
(leaving bookmark e)
$ hg merge
abort: heads are bookmarked - please merge with an explicit rev
(run 'hg heads' to see all heads, specify rev with -r)
[255]
# our revision is bookmarked
$ hg up -C e
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
(activating bookmark e)
$ hg merge
abort: no matching bookmark to merge - please merge with an explicit rev or bookmark
(run 'hg heads' to see all heads, specify rev with -r)
[255]
# merge bookmark heads
$ hg up -C 4
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
(leaving bookmark e)
$ echo f > f
$ hg commit -Am "f"
adding f
$ hg bookmarks -r 4 "e@diverged"
$ hg up -q -C "e@diverged"
$ hg merge
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg parents
changeset: 4:a0546fcfe0fb
bookmark: e@diverged
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: d
changeset: 5:26bee9c5bcf3
bookmark: e
parent: 3:b8f96cf4688b
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: e
$ hg up -C e
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
(activating bookmark e)
$ hg bookmarks
b 1:d2ae7f538514
c 3:b8f96cf4688b
* e 5:26bee9c5bcf3
e@diverged 4:a0546fcfe0fb
$ hg merge
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg commit -m'merge'
$ hg bookmarks
b 1:d2ae7f538514
c 3:b8f96cf4688b
* e 7:ca784329f0ba
# test warning when all heads are inactive bookmarks
$ hg up -C 6
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
(leaving bookmark e)
$ echo g > g
$ hg commit -Am 'g'
adding g
$ hg bookmark -i g
$ hg bookmarks
b 1:d2ae7f538514
c 3:b8f96cf4688b
e 7:ca784329f0ba
g 8:04dd21731d95
$ hg heads
changeset: 8:04dd21731d95
bookmark: g
tag: tip
parent: 6:be381d1126a0
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: g
changeset: 7:ca784329f0ba
bookmark: e
parent: 5:26bee9c5bcf3
parent: 4:a0546fcfe0fb
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: merge
$ hg merge
abort: heads are bookmarked - please merge with an explicit rev
(run 'hg heads' to see all heads, specify rev with -r)
[255]