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.
$ cat >> $HGRCPATH << EOF
> [extensions]
> show =
> EOF
No arguments shows available views
$ hg init empty
$ cd empty
$ hg show
available views:
bookmarks -- bookmarks and their associated changeset
stack -- current line of work
work -- changesets that aren't finished
abort: no view requested
(use "hg show VIEW" to choose a view)
[255]
`hg help show` prints available views
$ hg help show
hg show VIEW
show various repository information
A requested view of repository data is displayed.
If no view is requested, the list of available views is shown and the
command aborts.
Note:
There are no backwards compatibility guarantees for the output of this
command. Output may change in any future Mercurial release.
Consumers wanting stable command output should specify a template via
"-T/--template".
List of available views:
bookmarks bookmarks and their associated changeset
stack current line of work
work changesets that aren't finished
(use 'hg help -e show' to show help for the show extension)
options:
-T --template TEMPLATE display with template
(some details hidden, use --verbose to show complete help)
Unknown view prints error
$ hg show badview
abort: unknown view: badview
(run "hg show" to see available views)
[255]
HGPLAIN results in abort
$ HGPLAIN=1 hg show bookmarks
abort: must specify a template in plain mode
(invoke with -T/--template to control output format)
[255]
But not if a template is specified
$ HGPLAIN=1 hg show bookmarks -T '{bookmark}\n'
(no bookmarks set)
$ cd ..
bookmarks view with no bookmarks prints empty message
$ hg init books
$ cd books
$ touch f0
$ hg -q commit -A -m initial
$ hg show bookmarks
(no bookmarks set)
bookmarks view shows bookmarks in an aligned table
$ echo book1 > f0
$ hg commit -m 'commit for book1'
$ echo book2 > f0
$ hg commit -m 'commit for book2'
$ hg bookmark -r 1 book1
$ hg bookmark a-longer-bookmark
$ hg show bookmarks
* a-longer-bookmark 7b57
book1 b757
A custom bookmarks template works
$ hg show bookmarks -T '{node} {bookmark} {active}\n'
7b5709ab64cbc34da9b4367b64afff47f2c4ee83 a-longer-bookmark True
b757f780b8ffd71267c6ccb32e0882d9d32a8cc0 book1 False
bookmarks JSON works
$ hg show bookmarks -T json
[
{
"active": true,
"bookmark": "a-longer-bookmark",
"longestbookmarklen": 17,
"node": "7b5709ab64cbc34da9b4367b64afff47f2c4ee83",
"nodelen": 4
},
{
"active": false,
"bookmark": "book1",
"longestbookmarklen": 17,
"node": "b757f780b8ffd71267c6ccb32e0882d9d32a8cc0",
"nodelen": 4
}
]
JSON works with no bookmarks
$ hg book -d a-longer-bookmark
$ hg book -d book1
$ hg show bookmarks -T json
[
]
commands.show.aliasprefix aliases values to `show <view>`
$ hg --config commands.show.aliasprefix=s sbookmarks
(no bookmarks set)
$ hg --config commands.show.aliasprefix=sh shwork
@ 7b57 commit for book2
o b757 commit for book1
o ba59 initial
$ hg --config commands.show.aliasprefix='s sh' swork
@ 7b57 commit for book2
o b757 commit for book1
o ba59 initial
$ hg --config commands.show.aliasprefix='s sh' shwork
@ 7b57 commit for book2
o b757 commit for book1
o ba59 initial
The aliases don't appear in `hg config`
$ hg --config commands.show.aliasprefix=s config alias
[1]
Doesn't overwrite existing alias
$ hg --config alias.swork='log -r .' --config commands.show.aliasprefix=s swork
changeset: 2:7b5709ab64cb
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: commit for book2
$ hg --config alias.swork='log -r .' --config commands.show.aliasprefix=s config alias
alias.swork=log -r .
$ cd ..