tests/test-parentrevspec.t

check-code: catch Python 'is' comparing number or string literals

The Python 'is' operator compares object identity, so it should
definitely not be applied to string or number literals, which Python
implementations are free to represent with a temporary object.

This should catch the following kinds of bogus expressions (examples):

  x is 'foo'     x is not 'foo'
  x is "bar"     x is not "bar"
  x is 42        x is not 42
  x is -36       x is not -36

As originally proposed by Martin Geisler, amended with catching
negative numbers.

  $ commit()
  > {
  >     msg=$1
  >     p1=$2
  >     p2=$3
  > 
  >     if [ "$p1" ]; then
  >         hg up -qC $p1
  >     fi
  > 
  >     if [ "$p2" ]; then
  >         HGMERGE=true hg merge -q $p2
  >     fi
  > 
  >     echo >> foo
  > 
  >     hg commit -qAm "$msg"
  > }
  $ hg init repo
  $ cd repo
  $ echo '[extensions]' > .hg/hgrc
  $ echo 'parentrevspec =' >> .hg/hgrc
  $ commit '0: add foo'
  $ commit '1: change foo 1'
  $ commit '2: change foo 2a'
  $ commit '3: change foo 3a'
  $ commit '4: change foo 2b' 1
  $ commit '5: merge' 3 4
  $ commit '6: change foo again'
  $ hg log --template '{rev}:{node|short} {parents}\n'
  6:755d1e0d79e9 
  5:9ce2ce29723a 3:a3e00c7dbf11 4:bb4475edb621 
  4:bb4475edb621 1:5d953a1917d1 
  3:a3e00c7dbf11 
  2:befc7d89d081 
  1:5d953a1917d1 
  0:837088b6e1d9 
  $ echo
  
  $ lookup()
  > {
  >     for rev in "$@"; do
  >         printf "$rev: "
  >         hg id -nr $rev
  >     done
  >     true
  > }
  $ tipnode=`hg id -ir tip`

should work with tag/branch/node/rev

  $ for r in tip default $tipnode 6; do
  >     lookup "$r^"
  > done
  tip^: 5
  default^: 5
  755d1e0d79e9^: 5
  6^: 5
  $ echo
  

some random lookups

  $ lookup "6^^" "6^^^" "6^^^^" "6^^^^^" "6^^^^^^" "6^1" "6^2" "6^^2" "6^1^2" "6^^3"
  6^^: 3
  6^^^: 2
  6^^^^: 1
  6^^^^^: 0
  6^^^^^^: -1
  6^1: 5
  6^2: hg: parse error at 1: syntax error
  6^^2: 4
  6^1^2: 4
  6^^3: hg: parse error at 1: syntax error
  $ lookup "6~" "6~1" "6~2" "6~3" "6~4" "6~5" "6~42" "6~1^2" "6~1^2~2"
  6~: hg: parse error at 1: syntax error
  6~1: 5
  6~2: 3
  6~3: 2
  6~4: 1
  6~5: 0
  6~42: -1
  6~1^2: 4
  6~1^2~2: 0
  $ echo
  

with a tag "6^" pointing to rev 1

  $ hg tag -l -r 1 "6^"
  $ lookup "6^" "6^1" "6~1" "6^^"
  6^: 1
  6^1: 5
  6~1: 5
  6^^: 3
  $ echo
  

with a tag "foo^bar" pointing to rev 2

  $ hg tag -l -r 2 "foo^bar"
  $ lookup "foo^bar" "foo^bar^"
  foo^bar: 2
  foo^bar^: hg: parse error at 3: syntax error