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.

     1

Test hg log changeset printer external hook

     2

-------------------------------------------

     3

     4

  $ cat > $TESTTMP/logexthook.py <<EOF

     5

  > import codecs

     6

  > from mercurial import (

     7

  >   commands,

     8

  >   logcmdutil,

     9

  >   repair,

    10

  > )

    11

  > def brot13(b):

    12

  >     return codecs.encode(b.decode('utf8'), 'rot-13').encode('utf8')

    13

  > def rot13description(self, ctx):

    14

  >     description = ctx.description().strip().splitlines()[0]

    15

  >     self.ui.write(b"%s:     %s\n" % (brot13(b"summary"),

    16

  >                                      brot13(description)))

    17

  > def reposetup(ui, repo):

    18

  >     logcmdutil.changesetprinter._exthook = rot13description

    19

  > EOF

    20

    21

Prepare the repository

    22

    23

  $ hg init empty

    24

  $ cd empty

    25

  $ touch ROOT

    26

  $ hg commit -A -m "Root" ROOT

    27

    28

  $ touch a b c

    29

  $ hg commit -A -m "Add A, B, C" a b c

    30

    31

Check the log

    32

    33

  $ hg log --config extensions.t=$TESTTMP/logexthook.py

    34

  changeset:   1:70fc82b23320

    35

  tag:         tip

    36

  user:        test

    37

  date:        Thu Jan 01 00:00:00 1970 +0000

    38

  fhzznel:     Nqq N, O, P

    39

  summary:     Add A, B, C

    40

    41

  changeset:   0:b00443a54871

    42

  user:        test

    43

  date:        Thu Jan 01 00:00:00 1970 +0000

    44

  fhzznel:     Ebbg

    45

  summary:     Root

    46

    47

Check that exthook is working with graph log too

    48

    49

  $ hg log -G --config extensions.t=$TESTTMP/logexthook.py

    50

  @  changeset:   1:70fc82b23320

    51

  |  tag:         tip

    52

  |  user:        test

    53

  |  date:        Thu Jan 01 00:00:00 1970 +0000

    54

  |  fhzznel:     Nqq N, O, P

    55

  |  summary:     Add A, B, C

    56

  |

    57

  o  changeset:   0:b00443a54871

    58

     user:        test

    59

     date:        Thu Jan 01 00:00:00 1970 +0000

    60

     fhzznel:     Ebbg

    61

     summary:     Root

    62