annotate tests/test-casecollision-merge.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.

run only on case-insensitive filesystems

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

################################
test for branch merging
################################

test for rename awareness of case-folding collision check:

(1) colliding file is one renamed from collided file:
this is also case for issue3370.

  $ hg init branch_merge_renaming
  $ cd branch_merge_renaming

  $ echo a > a
  $ hg add a
  $ echo b > b
  $ hg add b
  $ hg commit -m '#0'
  $ hg tag -l A
  $ hg rename a tmp
  $ hg rename tmp A
  $ hg commit -m '#1'
  $ hg tag -l B
  $ hg update -q 0
  $ touch x
  $ hg add x
  $ hg commit -m '#2'
  created new head
  $ hg tag -l C

  $ hg merge -q
  $ hg status -A
  M A
  R a
  C b
  C x

  $ hg update -q --clean 1
  $ hg merge -q
  $ hg status -A
  M x
  C A
  C b
  $ hg commit -m '(D)'
  $ hg tag -l D

additional test for issue3452:

| this assumes the history below.
|
|  (A) -- (C) -- (E) -------
|      \      \             \
|       \      \             \
|         (B) -- (D) -- (F) -- (G)
|
|   A: add file 'a'
|   B: rename from 'a' to 'A'
|   C: add 'x' (or operation other than modification of 'a')
|   D: merge C into B
|   E: modify 'a'
|   F: modify 'A'
|   G: merge E into F
|
| issue3452 occurs when (B) is recorded before (C)

  $ hg update -q --clean C
  $ echo "modify 'a' at (E)" > a
  $ echo "modify 'b' at (E)" > b
  $ hg commit -m '(E)'
  created new head
  $ hg tag -l E

  $ hg update -q --clean D
  $ echo "modify 'A' at (F)" > A
  $ hg commit -m '(F)'
  $ hg tag -l F

  $ hg merge -q --tool internal:other E
  $ hg status -A
  M A
    a
  M b
  C x
  $ cat A
  modify 'a' at (E)

test also the case that (B) is recorded after (C), to prevent
regression by changes in the future.

to avoid unexpected (successful) behavior by filelog unification,
target file is not 'a'/'A' but 'b'/'B' in this case.

  $ hg update -q --clean A
  $ hg rename b tmp
  $ hg rename tmp B
  $ hg commit -m '(B1)'
  created new head
  $ hg tag -l B1

  $ hg merge -q C
  $ hg status -A
  M x
  C B
  C a
  $ hg commit -m '(D1)'
  $ hg tag -l D1

  $ echo "modify 'B' at (F1)" > B
  $ hg commit -m '(F1)'
  $ hg tag -l F1

  $ hg merge -q --tool internal:other E
  $ hg status -A
  M B
    b
  M a
  C x
  $ cat B
  modify 'b' at (E)

  $ cd ..

(2) colliding file is not related to collided file

  $ hg init branch_merge_collding
  $ cd branch_merge_collding

  $ echo a > a
  $ hg add a
  $ hg commit -m '#0'
  $ hg remove a
  $ hg commit -m '#1'
  $ echo A > A
  $ hg add A
  $ hg commit -m '#2'
  $ hg update --clean 0
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo x > x
  $ hg add x
  $ hg commit -m '#3'
  created new head
  $ echo 'modified at #4' > a
  $ hg commit -m '#4'

  $ hg merge
  abort: case-folding collision between a and A
  [255]
  $ hg parents --template '{rev}\n'
  4
  $ hg status -A
  C a
  C x
  $ cat a
  modified at #4

  $ hg update --clean 2
  1 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ hg merge
  abort: case-folding collision between a and A
  [255]
  $ hg parents --template '{rev}\n'
  2
  $ hg status -A
  C A
  $ cat A
  A

test for deletion awareness of case-folding collision check (issue3648):
revision '#3' doesn't change 'a', so 'a' should be recognized as
safely removed in merging between #2 and #3.

  $ hg update --clean 3
  2 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg merge 2
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg status -A
  M A
  R a
  C x

  $ hg update --clean 2
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg merge 3
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg status -A
  M x
  C A

  $ cd ..


################################
test for linear updates
################################

test for rename awareness of case-folding collision check:

(1) colliding file is one renamed from collided file

  $ hg init linearupdate_renameaware_1
  $ cd linearupdate_renameaware_1

  $ echo a > a
  $ hg add a
  $ hg commit -m '#0'
  $ hg rename a tmp
  $ hg rename tmp A
  $ hg commit -m '#1'

  $ hg update 0
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ echo 'this is added line' >> a
  $ hg update 1
  merging a and A to A
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  $ hg status -A
  M A
  $ cat A
  a
  this is added line

  $ cd ..

(2) colliding file is not related to collided file

  $ hg init linearupdate_renameaware_2
  $ cd linearupdate_renameaware_2

  $ echo a > a
  $ hg add a
  $ hg commit -m '#0'
  $ hg remove a
  $ hg commit -m '#1'
  $ echo A > A
  $ hg add A
  $ hg commit -m '#2'

  $ hg update 0
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg parents --template '{rev}\n'
  0
  $ hg status -A
  C a
  $ cat A
  a
  $ hg up -qC 2

  $ hg update --check 0
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg parents --template '{rev}\n'
  0
  $ hg status -A
  C a
  $ cat a
  a

  $ hg update --clean 2
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg parents --template '{rev}\n'
  2
  $ hg status -A
  C A
  $ cat A
  A

  $ cd ..

(3) colliding file is not related to collided file: added in working dir

  $ hg init linearupdate_renameaware_3
  $ cd linearupdate_renameaware_3

  $ echo a > a
  $ hg add a
  $ hg commit -m '#0'
  $ hg rename a b
  $ hg commit -m '#1'
  $ hg update 0
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ echo B > B
  $ hg add B
  $ hg status
  A B
  $ hg update
  abort: case-folding collision between b and B
  [255]

  $ hg update --check
  abort: uncommitted changes
  [255]

  $ hg update --clean
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg parents --template '{rev}\n'
  1
  $ hg status -A
  C b
  $ cat b
  a

  $ cd ..