view tests/test-share.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.

  $ "$TESTDIR/hghave" killdaemons || exit 80

  $ echo "[extensions]"      >> $HGRCPATH
  $ echo "share = "          >> $HGRCPATH

prepare repo1

  $ hg init repo1
  $ cd repo1
  $ echo a > a
  $ hg commit -A -m'init'
  adding a

share it

  $ cd ..
  $ hg share repo1 repo2
  updating working directory
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

share shouldn't have a store dir

  $ cd repo2
  $ test -d .hg/store
  [1]

Some sed versions appends newline, some don't, and some just fails

  $ cat .hg/sharedpath; echo
  $TESTTMP/repo1/.hg (glob)

trailing newline on .hg/sharedpath is ok
  $ hg tip -q
  0:d3873e73d99e
  $ echo '' >> .hg/sharedpath
  $ cat .hg/sharedpath
  $TESTTMP/repo1/.hg (glob)
  $ hg tip -q
  0:d3873e73d99e

commit in shared clone

  $ echo a >> a
  $ hg commit -m'change in shared clone'

check original

  $ cd ../repo1
  $ hg log
  changeset:   1:8af4dc49db9e
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     change in shared clone
  
  changeset:   0:d3873e73d99e
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     init
  
  $ hg update
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cat a             # should be two lines of "a"
  a
  a

commit in original

  $ echo b > b
  $ hg commit -A -m'another file'
  adding b

check in shared clone

  $ cd ../repo2
  $ hg log
  changeset:   2:c2e0ac586386
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     another file
  
  changeset:   1:8af4dc49db9e
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     change in shared clone
  
  changeset:   0:d3873e73d99e
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     init
  
  $ hg update
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cat b             # should exist with one "b"
  b

hg serve shared clone

  $ hg serve -n test -p $HGPORT -d --pid-file=hg.pid
  $ cat hg.pid >> $DAEMON_PIDS
  $ "$TESTDIR/get-with-headers.py" localhost:$HGPORT 'raw-file/'
  200 Script output follows
  
  
  -rw-r--r-- 4 a
  -rw-r--r-- 2 b
  
  

test unshare command

  $ hg unshare
  $ test -d .hg/store
  $ test -f .hg/sharedpath
  [1]
  $ hg unshare
  abort: this is not a shared repo
  [255]

check that a change does not propagate

  $ echo b >> b
  $ hg commit -m'change in unshared'
  $ cd ../repo1
  $ hg id -r tip
  c2e0ac586386 tip

  $ cd ..

Explicitly kill daemons to let the test exit on Windows

  $ "$TESTDIR/killdaemons.py" $DAEMON_PIDS