view tests/test-bookmarks-current.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.

  $ hg init

no bookmarks

  $ hg bookmarks
  no bookmarks set

set bookmark X

  $ hg bookmark X

list bookmarks

  $ hg bookmark
   * X                         -1:000000000000

list bookmarks with color

  $ hg --config extensions.color= --config color.mode=ansi \
  >     bookmark --color=always
  \x1b[0;32m * X                         -1:000000000000\x1b[0m (esc)

update to bookmark X

  $ hg update X
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved

list bookmarks

  $ hg bookmarks
   * X                         -1:000000000000

rename

  $ hg bookmark -m X Z

list bookmarks

  $ cat .hg/bookmarks.current
  Z (no-eol)
  $ cat .hg/bookmarks
  0000000000000000000000000000000000000000 Z
  $ hg bookmarks
   * Z                         -1:000000000000

new bookmarks X and Y, first one made active

  $ hg bookmark Y X

list bookmarks

  $ hg bookmark
     X                         -1:000000000000
   * Y                         -1:000000000000
     Z                         -1:000000000000

  $ hg bookmark -d X

commit

  $ echo 'b' > b
  $ hg add b
  $ hg commit -m'test'

list bookmarks

  $ hg bookmark
   * Y                         0:719295282060
     Z                         -1:000000000000

Verify that switching to Z updates the current bookmark:
  $ hg update Z
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg bookmark
     Y                         0:719295282060
   * Z                         -1:000000000000

Switch back to Y for the remaining tests in this file:
  $ hg update Y
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

delete bookmarks

  $ hg bookmark -d Y
  $ hg bookmark -d Z

list bookmarks

  $ hg bookmark
  no bookmarks set

update to tip

  $ hg update tip
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved

set bookmark Y using -r . but make sure that the active
bookmark is not activated

  $ hg bookmark -r . Y

list bookmarks, Y should not be active

  $ hg bookmark
     Y                         0:719295282060

now, activate Y

  $ hg up -q Y

set bookmark Z using -i

  $ hg bookmark -r . -i Z
  $ hg bookmarks
   * Y                         0:719295282060
     Z                         0:719295282060

deactivate current bookmark using -i

  $ hg bookmark -i Y
  $ hg bookmarks
     Y                         0:719295282060
     Z                         0:719295282060

  $ hg up -q Y
  $ hg bookmark -i
  $ hg bookmarks
     Y                         0:719295282060
     Z                         0:719295282060
  $ hg bookmark -i
  no active bookmark
  $ hg up -q Y
  $ hg bookmarks
   * Y                         0:719295282060
     Z                         0:719295282060

deactivate current bookmark while renaming

  $ hg bookmark -i -m Y X
  $ hg bookmarks
     X                         0:719295282060
     Z                         0:719295282060

bare update moves the active bookmark forward and clear the divergent bookmarks

  $ echo a > a
  $ hg ci -Am1
  adding a
  $ echo b >> a
  $ hg ci -Am2
  $ hg bookmark X@1 -r 1
  $ hg bookmark X@2 -r 2
  $ hg update X
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg bookmarks
   * X                         0:719295282060
     X@1                       1:cc586d725fbe
     X@2                       2:49e1c4e84c58
     Z                         0:719295282060
  $ hg update
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updating bookmark X
  $ hg bookmarks
   * X                         2:49e1c4e84c58
     Z                         0:719295282060

test deleting .hg/bookmarks.current when explicitly updating
to a revision

  $ echo a >> b
  $ hg ci -m.
  $ hg up -q X
  $ test -f .hg/bookmarks.current

try to update to it again to make sure we don't
set and then unset it

  $ hg up -q X
  $ test -f .hg/bookmarks.current

  $ hg up -q 1
  $ test -f .hg/bookmarks.current
  [1]

when a bookmark is active, hg up -r . is
analogus to hg book -i <active bookmark>

  $ hg up -q X
  $ hg up -q .
  $ test -f .hg/bookmarks.current
  [1]