view tests/test-purge.t @ 20742:3681de20b0a7

parsers: fail fast if Python has wrong minor version (issue4110)

This change causes an informative ImportError to be raised when importing
the parsers extension module if the minor version of the currently-running
Python interpreter doesn't match that of the Python used when compiling
the extension module.

This change also exposes a parsers.versionerrortext constant in the
C implementation of the module.  Its presence can be used to determine
whether this behavior is present in a version of the module.  The value
of the constant is the leading text of the ImportError raised and is set
to "Python minor version mismatch".

Here is an example of what the new error looks like:

  Traceback (most recent call last):
    File "test.py", line 1, in <module>
      import mercurial.parsers
  ImportError: Python minor version mismatch: The Mercurial extension
  modules were compiled with Python 2.7.6, but Mercurial is currently using
  Python with sys.hexversion=33883888: Python 2.5.6
  (r256:88840, Nov 18 2012, 05:37:10)
  [GCC 4.2.1 Compatible Apple Clang 4.1 ((tags/Apple/clang-421.11.66))]
   at: /opt/local/Library/Frameworks/Python.framework/Versions/2.5/Resources/
    Python.app/Contents/MacOS/Python

The reason for raising an error in this scenario is that Python's C API
is known not to be compatible from minor version to minor version, even
if sys.api_version is the same.  See for example this Python bug report
about incompatibilities between 2.5 and 2.6+:

  http://bugs.python.org/issue8118

These incompatibilities can cause Mercurial to break in mysterious,
unforeseen ways.  For example, when Mercurial compiled with Python 2.7 was
run with 2.5, the following crash occurred when running "hg status":

  http://bz.selenic.com/show_bug.cgi?id=4110

After this crash was fixed, running with Python 2.5 no longer crashes, but
the following puzzling behavior still occurs:

    $ hg status
      ...
      File ".../mercurial/changelog.py", line 123, in __init__
        revlog.revlog.__init__(self, opener, "00changelog.i")
      File ".../mercurial/revlog.py", line 251, in __init__
        d = self._io.parseindex(i, self._inline)
      File ".../mercurial/revlog.py", line 158, in parseindex
        index, cache = parsers.parse_index2(data, inline)
    TypeError: data is not a string

which can be reproduced more simply with:

    import mercurial.parsers as parsers
    parsers.parse_index2("", True)

Both the crash and the TypeError occurred because the Python C API's
PyString_Check() returns the wrong value when the C header files from
Python 2.7 are run with Python 2.5.  This is an example of an
incompatibility of the sort mentioned in the Python bug report above.

Failing fast with an informative error message results in a better user
experience in cases like the above.  The information in the ImportError
also simplifies troubleshooting for those on Mercurial mailing lists, the
bug tracker, etc.

This patch only adds the version check to parsers.c, which is sufficient
to affect command-line commands like "hg status" and "hg summary".
An idea for a future improvement is to move the version-checking C code
to a more central location, and have it run when importing all
Mercurial extension modules and not just parsers.c.

  $ cat <<EOF >> $HGRCPATH
  > [extensions]
  > purge =
  > EOF

init

  $ hg init t
  $ cd t

setup

  $ echo r1 > r1
  $ hg ci -qAmr1 -d'0 0'
  $ mkdir directory
  $ echo r2 > directory/r2
  $ hg ci -qAmr2 -d'1 0'
  $ echo 'ignored' > .hgignore
  $ hg ci -qAmr3 -d'2 0'

delete an empty directory

  $ mkdir empty_dir
  $ hg purge -p -v
  empty_dir
  $ hg purge -v
  removing directory empty_dir
  $ ls
  directory
  r1

delete an untracked directory

  $ mkdir untracked_dir
  $ touch untracked_dir/untracked_file1
  $ touch untracked_dir/untracked_file2
  $ hg purge -p
  untracked_dir/untracked_file1
  untracked_dir/untracked_file2
  $ hg purge -v
  removing file untracked_dir/untracked_file1
  removing file untracked_dir/untracked_file2
  removing directory untracked_dir
  $ ls
  directory
  r1

delete an untracked file

  $ touch untracked_file
  $ touch untracked_file_readonly
  $ python <<EOF
  > import os, stat
  > f= 'untracked_file_readonly'
  > os.chmod(f, stat.S_IMODE(os.stat(f).st_mode) & ~stat.S_IWRITE)
  > EOF
  $ hg purge -p
  untracked_file
  untracked_file_readonly
  $ hg purge -v
  removing file untracked_file
  removing file untracked_file_readonly
  $ ls
  directory
  r1

delete an untracked file in a tracked directory

  $ touch directory/untracked_file
  $ hg purge -p
  directory/untracked_file
  $ hg purge -v
  removing file directory/untracked_file
  $ ls
  directory
  r1

delete nested directories

  $ mkdir -p untracked_directory/nested_directory
  $ hg purge -p
  untracked_directory/nested_directory
  $ hg purge -v
  removing directory untracked_directory/nested_directory
  removing directory untracked_directory
  $ ls
  directory
  r1

delete nested directories from a subdir

  $ mkdir -p untracked_directory/nested_directory
  $ cd directory
  $ hg purge -p
  untracked_directory/nested_directory
  $ hg purge -v
  removing directory untracked_directory/nested_directory
  removing directory untracked_directory
  $ cd ..
  $ ls
  directory
  r1

delete only part of the tree

  $ mkdir -p untracked_directory/nested_directory
  $ touch directory/untracked_file
  $ cd directory
  $ hg purge -p ../untracked_directory
  untracked_directory/nested_directory
  $ hg purge -v ../untracked_directory
  removing directory untracked_directory/nested_directory
  removing directory untracked_directory
  $ cd ..
  $ ls
  directory
  r1
  $ ls directory/untracked_file
  directory/untracked_file
  $ rm directory/untracked_file

skip ignored files if --all not specified

  $ touch ignored
  $ hg purge -p
  $ hg purge -v
  $ ls
  directory
  ignored
  r1
  $ hg purge -p --all
  ignored
  $ hg purge -v --all
  removing file ignored
  $ ls
  directory
  r1

abort with missing files until we support name mangling filesystems

  $ touch untracked_file
  $ rm r1

hide error messages to avoid changing the output when the text changes

  $ hg purge -p 2> /dev/null
  untracked_file
  $ hg st
  ! r1
  ? untracked_file

  $ hg purge -p
  untracked_file
  $ hg purge -v 2> /dev/null
  removing file untracked_file
  $ hg st
  ! r1

  $ hg purge -v
  $ hg revert --all --quiet
  $ hg st -a

tracked file in ignored directory (issue621)

  $ echo directory >> .hgignore
  $ hg ci -m 'ignore directory'
  $ touch untracked_file
  $ hg purge -p
  untracked_file
  $ hg purge -v
  removing file untracked_file

skip excluded files

  $ touch excluded_file
  $ hg purge -p -X excluded_file
  $ hg purge -v -X excluded_file
  $ ls
  directory
  excluded_file
  r1
  $ rm excluded_file

skip files in excluded dirs

  $ mkdir excluded_dir
  $ touch excluded_dir/file
  $ hg purge -p -X excluded_dir
  $ hg purge -v -X excluded_dir
  $ ls
  directory
  excluded_dir
  r1
  $ ls excluded_dir
  file
  $ rm -R excluded_dir

skip excluded empty dirs

  $ mkdir excluded_dir
  $ hg purge -p -X excluded_dir
  $ hg purge -v -X excluded_dir
  $ ls
  directory
  excluded_dir
  r1
  $ rmdir excluded_dir

skip patterns

  $ mkdir .svn
  $ touch .svn/foo
  $ mkdir directory/.svn
  $ touch directory/.svn/foo
  $ hg purge -p -X .svn -X '*/.svn'
  $ hg purge -p -X re:.*.svn

  $ cd ..