tests/test-dispatch.t

vfs: use checkambigatclosing in checkambig=True but atomictemp=False case

In Mercurial source tree, opening a file in "a"/"a+" mode like below
doesn't specify atomictemp=True for vfs, and this avoids file stat
ambiguity check by atomictempfile.

  - writing changes out in revlog layer uses "a+" mode
  - truncation in repair.strip() uses "a" mode
  - truncation in transaction._playback() uses "a" mode

If steps below occurs at "the same time in sec", all of mtime, ctime
and size are same between (1) and (3).

  1. append data to revlog-style file (and close transaction)
  2. discard appended data by truncation (strip or rollback)
  3. append same size but different data to revlog-style file again

Therefore, cache validation doesn't work after (3) as expected.

This patch uses checkambigatclosing in checkambig=True but
atomictemp=False case, to check (and get rid of) file stat ambiguity
at closing.

This is a part of ExactCacheValidationPlan.

    https://www.mercurial-scm.org/wiki/ExactCacheValidationPlan

test command parsing and dispatch

  $ hg init a
  $ cd a

Redundant options used to crash (issue436):
  $ hg -v log -v
  $ hg -v log -v x

  $ echo a > a
  $ hg ci -Ama
  adding a

Missing arg:

  $ hg cat
  hg cat: invalid arguments
  hg cat [OPTION]... FILE...
  
  output the current or given revision of files
  
  options ([+] can be repeated):
  
   -o --output FORMAT       print output to file with formatted name
   -r --rev REV             print the given revision
      --decode              apply any matching decode filter
   -I --include PATTERN [+] include names matching the given patterns
   -X --exclude PATTERN [+] exclude names matching the given patterns
  
  (use 'hg cat -h' to show more help)
  [255]

[defaults]

  $ hg cat a
  a
  $ cat >> $HGRCPATH <<EOF
  > [defaults]
  > cat = -r null
  > EOF
  $ hg cat a
  a: no such file in rev 000000000000
  [1]

  $ cd "$TESTTMP"

OSError "No such file or directory" / "The system cannot find the path
specified" should include filename even when it is empty

  $ hg -R a archive ''
  abort: *: '' (glob)
  [255]

#if no-outer-repo

No repo:

  $ hg cat
  abort: no repository found in '$TESTTMP' (.hg not found)!
  [255]

#endif