tests/test-patch.t

transaction: separate calculating TXNID from creating transaction object

Before this patch, transaction ID (TXNID) is calculated from
`transaction` object itself by `id()`, but this prevents TXNID from
being passed to `pretxnopen` hooks, which should be executed before
starting transaction processing (also any preparations for it, like
writing journal files out).

As a preparation for passing TXNID to `pretxnopen` hooks, this patch
separates calculation of TXNID from creation of `transaction` object.

This patch uses "random" library for reasonable unique ID. "uuid"
library can't be used, because it was introduced since Python 2.5 and
isn't suitable for Mercurial 3.4.x stable line.

`%f` formatting for `random.random()` is used with explicit precision
number 40, because default precision for `%f` is 6. 40 should be long
enough, even if 10**9 transactions are executed in a short time (a
second or less).

On the other hand, `time.time()` is used to ensures uniqueness of
TXNID in a long time, for safety.

BTW, platform not providing `/dev/urandom` or so may cause failure of
`import random` itself with some Python versions (see Python
issue15340 for detail http://bugs.python.org/issue15340).

But this patch uses "random" without any workaround, because:

  - "random" is already used directly in some code paths,
  - such platforms are very rare (e.g. Tru64 and HPUX), and
    http://bugs.python.org/issue15340#msg170000
  - updating Python runtime can avoid this issue

  $ cat > patchtool.py <<EOF
  > import sys
  > print 'Using custom patch'
  > if '--binary' in sys.argv:
  >     print '--binary found !'
  > EOF

  $ echo "[ui]" >> $HGRCPATH
  $ echo "patch=python ../patchtool.py" >> $HGRCPATH

  $ hg init a
  $ cd a
  $ echo a > a
  $ hg commit -Ama -d '1 0'
  adding a
  $ echo b >> a
  $ hg commit -Amb -d '2 0'
  $ cd ..

This test checks that:
 - custom patch commands with arguments actually work
 - patch code does not try to add weird arguments like
 --binary when custom patch commands are used. For instance
 --binary is added by default under win32.

check custom patch options are honored

  $ hg --cwd a export -o ../a.diff tip
  $ hg clone -r 0 a b
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ hg --cwd b import -v ../a.diff
  applying ../a.diff
  Using custom patch
  applied to working directory

Issue2417: hg import with # comments in description

Prepare source repo and patch:

  $ rm $HGRCPATH
  $ hg init c
  $ cd c
  $ printf "a\rc" > a
  $ hg ci -A -m 0 a -d '0 0'
  $ printf "a\rb\rc" > a
  $ cat << eof > log
  > first line which can't start with '# '
  > # second line is a comment but that shouldn't be a problem.
  > A patch marker like this was more problematic even after d7452292f9d3:
  > # HG changeset patch
  > # User lines looks like this - but it _is_ just a comment
  > eof
  $ hg ci -l log -d '0 0'
  $ hg export -o p 1
  $ cd ..

Clone and apply patch:

  $ hg clone -r 0 c d
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd d
  $ hg import ../c/p
  applying ../c/p
  $ hg log -v -r 1
  changeset:   1:cd0bde79c428
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       a
  description:
  first line which can't start with '# '
  # second line is a comment but that shouldn't be a problem.
  A patch marker like this was more problematic even after d7452292f9d3:
  # HG changeset patch
  # User lines looks like this - but it _is_ just a comment
  
  
  $ cd ..