view mercurial/txnutil.py @ 49417:075a553028e2

tests: work around libmagic bug in svn subrepo tests

libmagic 5.40 introduced a bug [1] wherein ASCII text files with fewer
than 3 distinct character values would be reported as binary data
rather than as text. This bug was later fixed in version 5.41 [2].

SVN uses libmagic to determine the MIME type of added files with missing
or unknown extensions [3]. This results in test failures on systems with
libmagic 5.40 installed:

   $ echo a > a
   $ svn add a
-  A         a
+  A  (bin)  a

A simple workaround is to change the test file's content to include
3 distinct ASCII values (including the terminating newline).

[1] https://bugs.astron.com/view.php?id=180
[2] https://bugs.astron.com/view.php?id=261
[3] https://svnbook.red-bean.com/en/1.8/svn.advanced.props.html#idm2649

# txnutil.py - transaction related utilities
#
#  Copyright FUJIWARA Katsunori <[e-mail]> and others
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.


from . import encoding


def mayhavepending(root):
    """return whether 'root' may have pending changes, which are
    visible to this process.
    """
    return root == encoding.environ.get(b'HG_PENDING')


def trypending(root, vfs, filename, **kwargs):
    """Open  file to be read according to HG_PENDING environment variable

    This opens '.pending' of specified 'filename' only when HG_PENDING
    is equal to 'root'.

    This returns '(fp, is_pending_opened)' tuple.
    """
    if mayhavepending(root):
        try:
            return (vfs(b'%s.pending' % filename, **kwargs), True)
        except FileNotFoundError:
            pass
    return (vfs(filename, **kwargs), False)