tests/test-pull-network.t

filemerge: add support for partial conflict resolution by external tool

A common class of merge conflicts is in imports/#includes/etc. It's
relatively easy to write a tool that can resolve these conflicts,
perhaps by naively just unioning the statements and leaving any
cleanup to other tools to do later [1]. Such specialized tools cannot
generally resolve all conflicts in a file, of course. Let's therefore
call them "partial merge tools". Note that the internal simplemerge
algorithm is such a partial merge tool - one that only resolves
trivial "conflicts" where one side is unchanged or both sides change
in the same way.

One can also imagine having smarter language-aware partial tools that
merge the AST. It may be useful for such tools to interactively let
the user resolve any conflicts it can't resolve itself. However,
having the option of implementing it as a partial merge tool means
that the developer doesn't *need* to create a UI for it. Instead, the
user can resolve any remaining conflicts with their regular merge tool
(e.g. `:merge3` or `meld).

We don't currently have a way to let the user define such partial
merge tools. That's what this patch addresses. It lets the user
configure partial merge tools to run. Each tool can be configured to
run only on files matching certain patterns (e.g. "*.py"). The tool
takes three inputs (local, base, other) and resolves conflicts by
updating these in place. For example, let's say the inputs are these:


base:
```
import sys

def main():
  print('Hello')
```

local:
```
import os
import sys

def main():
  print('Hi')
```

other:
```
import re
import sys

def main():
  print('Howdy')
```

A partial merge tool could now resolve the conflicting imports by
replacing the import statements in *all* files by the following
snippet, while leaving the remainder of the files unchanged.

```
import os
import re
import sys
```

As a result, simplemerge and any regular merge tool that runs after
the partial merge tool(s) will consider the imports to be
non-conflicting and will only present the conflict in `main()` to the
user.

Differential Revision: https://phab.mercurial-scm.org/D12356

#require serve

  $ hg init test
  $ cd test

  $ echo foo>foo
  $ hg addremove
  adding foo
  $ hg commit -m 1

  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 1 changesets with 1 changes to 1 files

  $ hg serve -p $HGPORT -d --pid-file=hg.pid
  $ cat hg.pid >> $DAEMON_PIDS
  $ cd ..

  $ hg clone --pull http://foo:bar@localhost:$HGPORT/ copy
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  new changesets 340e38bdcde4
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ cd copy
  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 1 changesets with 1 changes to 1 files

  $ hg co
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cat foo
  foo

  $ hg manifest --debug
  2ed2a3912a0b24502043eae84ee4b279c18b90dd 644   foo

  $ hg pull
  pulling from http://foo@localhost:$HGPORT/
  searching for changes
  no changes found

  $ hg rollback --dry-run --verbose
  repository tip rolled back to revision -1 (undo pull: http://foo:***@localhost:$HGPORT/)

Test pull of non-existing 20 character revision specification, making sure plain ascii identifiers
not are encoded like a node:

  $ hg pull -r 'xxxxxxxxxxxxxxxxxxxy'
  pulling from http://foo@localhost:$HGPORT/
  abort: unknown revision 'xxxxxxxxxxxxxxxxxxxy'
  [255]
  $ hg pull -r 'xxxxxxxxxxxxxxxxxx y'
  pulling from http://foo@localhost:$HGPORT/
  abort: unknown revision 'xxxxxxxxxxxxxxxxxx y'
  [255]

Test pull of working copy revision
  $ hg pull -r 'ffffffffffff'
  pulling from http://foo@localhost:$HGPORT/
  abort: unknown revision 'ffffffffffff'
  [255]

Test 'file:' uri handling:

  $ hg pull -q file://../test-does-not-exist
  abort: file:// URLs can only refer to localhost
  [255]

  $ hg pull -q file://../test
  abort: file:// URLs can only refer to localhost
  [255]

MSYS changes 'file:' into 'file;'

#if no-msys
  $ hg pull -q file:../test  # no-msys
#endif

It's tricky to make file:// URLs working on every platform with
regular shell commands.

  $ URL=`"$PYTHON" -c "import os; print('file://foobar' + ('/' + os.getcwd().replace(os.sep, '/')).replace('//', '/') + '/../test')"`
  $ hg pull -q "$URL"
  abort: file:// URLs can only refer to localhost
  [255]

  $ URL=`"$PYTHON" -c "import os; print('file://localhost' + ('/' + os.getcwd().replace(os.sep, '/')).replace('//', '/') + '/../test')"`
  $ hg pull -q "$URL"

SEC: check for unsafe ssh url

  $ cat >> $HGRCPATH << EOF
  > [ui]
  > ssh = sh -c "read l; read l; read l"
  > EOF

  $ hg pull 'ssh://-oProxyCommand=touch${IFS}owned/path'
  pulling from ssh://-oProxyCommand%3Dtouch%24%7BIFS%7Downed/path
  abort: potentially unsafe url: 'ssh://-oProxyCommand=touch${IFS}owned/path'
  [255]
  $ hg pull 'ssh://%2DoProxyCommand=touch${IFS}owned/path'
  pulling from ssh://-oProxyCommand%3Dtouch%24%7BIFS%7Downed/path
  abort: potentially unsafe url: 'ssh://-oProxyCommand=touch${IFS}owned/path'
  [255]
  $ hg pull 'ssh://fakehost|touch${IFS}owned/path'
  pulling from ssh://fakehost%7Ctouch%24%7BIFS%7Downed/path
  abort: no suitable response from remote hg
  [255]
  $ hg --config ui.timestamp-output=true pull 'ssh://fakehost%7Ctouch%20owned/path'
  \[20[2-9][0-9]-[01][0-9]-[0-3][0-9]T[0-5][0-9]:[0-5][0-9]:[0-5][0-9]\.[0-9][0-9][0-9][0-9][0-9][0-9]\] pulling from ssh://fakehost%7Ctouch%20owned/path (re)
  \[20[2-9][0-9]-[01][0-9]-[0-3][0-9]T[0-5][0-9]:[0-5][0-9]:[0-5][0-9]\.[0-9][0-9][0-9][0-9][0-9][0-9]\] abort: no suitable response from remote hg (re)
  [255]

  $ [ ! -f owned ] || echo 'you got owned'

  $ cd ..