view tests/test-merge-internal-tools-pattern.t @ 26375:3686fa2b8eee

windows: insert file positioning call between reads and writes

fopen() and fdopen() have a unique-to-Windows requirement that
transitions between read and write operations in files opened
in modes r+, w+, and a+ perform a file positioning call
(fsetpos, fseek, or rewind) in between. While the MSDN docs don't
say what will happen if this is not done, observations reveal
that Python raises an IOError with errno 0. Furthermore, I
/think/ this behavior isn't deterministic. But I can reproduce
it reliably with subsequent patches applied that open revlogs
in a+ mode and perform both reads and writes.

This patch introduces a proxy class for file handles opened
in r+, w+, and a+ mode on Windows. The class intercepts calls
and audits whether a file positioning function has been called
between read and write operations. If not, a dummy, no-op seek
to the current file position is performed. This appears to be
sufficient to "trick" Windows into allowing transitions between
read and writes without raising errors.

Make sure that the internal merge tools (internal:fail, internal:local,
internal:union and internal:other) are used when matched by a
merge-pattern in hgrc

Make sure HGMERGE doesn't interfere with the test:

  $ unset HGMERGE

  $ hg init

Initial file contents:

  $ echo "line 1" > f
  $ echo "line 2" >> f
  $ echo "line 3" >> f
  $ hg ci -Am "revision 0"
  adding f

  $ cat f
  line 1
  line 2
  line 3

Branch 1: editing line 1:

  $ sed 's/line 1/first line/' f > f.new
  $ mv f.new f
  $ hg ci -Am "edited first line"

Branch 2: editing line 3:

  $ hg update 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ sed 's/line 3/third line/' f > f.new
  $ mv f.new f
  $ hg ci -Am "edited third line"
  created new head

Merge using internal:fail tool:

  $ echo "[merge-patterns]" > .hg/hgrc
  $ echo "* = internal:fail" >> .hg/hgrc

  $ hg merge
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
  [1]

  $ cat f
  line 1
  line 2
  third line

  $ hg stat
  M f

Merge using internal:local tool:

  $ hg update -C 2
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ sed 's/internal:fail/internal:local/' .hg/hgrc > .hg/hgrc.new
  $ mv .hg/hgrc.new .hg/hgrc

  $ hg merge
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ cat f
  line 1
  line 2
  third line

  $ hg stat
  M f

Merge using internal:other tool:

  $ hg update -C 2
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ sed 's/internal:local/internal:other/' .hg/hgrc > .hg/hgrc.new
  $ mv .hg/hgrc.new .hg/hgrc

  $ hg merge
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ cat f
  first line
  line 2
  line 3

  $ hg stat
  M f

Merge using default tool:

  $ hg update -C 2
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ rm .hg/hgrc

  $ hg merge
  merging f
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ cat f
  first line
  line 2
  third line

  $ hg stat
  M f

Merge using internal:union tool:

  $ hg update -C 2
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ echo "line 4a" >>f
  $ hg ci -Am "Adding fourth line (commit 4)"
  $ hg update 2
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ echo "line 4b" >>f
  $ hg ci -Am "Adding fourth line v2 (commit 5)"
  created new head

  $ echo "[merge-patterns]" > .hg/hgrc
  $ echo "* = internal:union" >> .hg/hgrc

  $ hg merge 3
  merging f
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ cat f
  line 1
  line 2
  third line
  line 4b
  line 4a