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

#require no-symlink

     2

     3

# The following script was used to create the bundle:

     4

#

     5

# hg init symlinks

     6

# cd symlinks

     7

# echo a > a

     8

# mkdir d

     9

# echo b > d/b

    10

# ln -s a a.lnk

    11

# ln -s d/b d/b.lnk

    12

# hg ci -Am t

    13

# hg bundle --base null ../test-no-symlinks.hg

    14

    15

Extract a symlink on a platform not supporting them

    16

    17

  $ hg init t

    18

  $ cd t

    19

  $ hg pull -q "$TESTDIR/bundles/test-no-symlinks.hg"

    20

  $ hg update

    21

  4 files updated, 0 files merged, 0 files removed, 0 files unresolved

    22

  $ cat a.lnk && echo

    23

  a

    24

  $ cat d/b.lnk && echo

    25

  d/b

    26

    27

Copy a symlink and move another

    28

    29

  $ hg copy a.lnk d/a2.lnk

    30

  $ hg mv d/b.lnk b2.lnk

    31

  $ hg ci -Am copy

    32

  $ cat d/a2.lnk && echo

    33

  a

    34

  $ cat b2.lnk && echo

    35

  d/b

    36

    37

Bundle and extract again

    38

    39

  $ hg bundle --base null ../symlinks.hg

    40

  2 changesets found

    41

  $ cd ..

    42

  $ hg init t2

    43

  $ cd t2

    44

  $ hg pull ../symlinks.hg

    45

  pulling from ../symlinks.hg

    46

  requesting all changes

    47

  adding changesets

    48

  adding manifests

    49

  adding file changes

    50

  added 2 changesets with 6 changes to 6 files

    51

  new changesets d326ae2d01ee:71d85cf3ba90 (2 drafts)

    52

  (run 'hg update' to get a working copy)

    53

  $ hg update

    54

  5 files updated, 0 files merged, 0 files removed, 0 files unresolved

    55

  $ cat a.lnk && echo

    56

  a

    57

  $ cat d/a2.lnk && echo

    58

  a

    59

  $ cat b2.lnk && echo

    60

  d/b