tests/test-issue660.t

match: introduce boolean prefix() method

tl;dr: This is another step towards a (previously unstated) goal of
eliminating match.files() in conditions.

There are four types of matchers:

 * always: Matches everything, checked with always(), files() is empty

 * exact: Matches exact set of files, checked with isexact(), files()
   contains the files to match

 * patterns: Matches more complex patterns, checked with anypats(),
   files() contains roots of the matched patterns

 * prefix: Matches simple 'path:' patterns as prefixes ('foo' matches
   both 'foo' and 'foo/bar'), no single method to check, files()
   contains the prefixes to match

For completeness, it would be nice to have a method for checking for
the "prefix" type of matcher as well, so let's add that, making it
return True simply when none of the others do.

The larger goal here is to eliminate uses of match.files() in
conditions (i.e. bool(match.files())). The reason for this is that
there are scenarios when you would like to create a "prefix" matcher
that happens to match no files. One example is for 'hg files -I foo
bar'. The narrowmatcher also restricts the set of files given and it
would not surprise me if have bugs caused by that already. Note that
'if m.files() and not m.anypats()' and similar is sometimes used to
catch the "exact" and "prefix" cases above.

http://mercurial.selenic.com/bts/issue660 and:
http://mercurial.selenic.com/bts/issue322

  $ hg init
  $ echo a > a
  $ mkdir b
  $ echo b > b/b
  $ hg commit -A -m "a is file, b is dir"
  adding a
  adding b/b

File replaced with directory:

  $ rm a
  $ mkdir a
  $ echo a > a/a

Should fail - would corrupt dirstate:

  $ hg add a/a
  abort: file 'a' in dirstate clashes with 'a/a'
  [255]

Removing shadow:

  $ hg rm --after a

Should succeed - shadow removed:

  $ hg add a/a

Directory replaced with file:

  $ rm -r b
  $ echo b > b

Should fail - would corrupt dirstate:

  $ hg add b
  abort: directory 'b' already in dirstate
  [255]

Removing shadow:

  $ hg rm --after b/b

Should succeed - shadow removed:

  $ hg add b

Look what we got:

  $ hg st
  A a/a
  A b
  R a
  R b/b

Revert reintroducing shadow - should fail:

  $ rm -r a b
  $ hg revert b/b
  abort: file 'b' in dirstate clashes with 'b/b'
  [255]

Revert all - should succeed:

  $ hg revert --all
  undeleting a
  forgetting a/a (glob)
  forgetting b
  undeleting b/b (glob)

  $ hg st

Issue3423:

  $ hg forget a
  $ echo zed > a
  $ hg revert a
  $ hg st
  ? a.orig
  $ rm a.orig

addremove:

  $ rm -r a b
  $ mkdir a
  $ echo a > a/a
  $ echo b > b

  $ hg addremove -s 0
  removing a
  adding a/a
  adding b
  removing b/b

  $ hg st
  A a/a
  A b
  R a
  R b/b

commit:

  $ hg ci -A -m "a is dir, b is file"
  $ hg st --all
  C a/a
  C b

Long directory replaced with file:

  $ mkdir d
  $ mkdir d/d
  $ echo d > d/d/d
  $ hg commit -A -m "d is long directory"
  adding d/d/d

  $ rm -r d
  $ echo d > d

Should fail - would corrupt dirstate:

  $ hg add d
  abort: directory 'd' already in dirstate
  [255]

Removing shadow:

  $ hg rm --after d/d/d

Should succeed - shadow removed:

  $ hg add d
  $ hg ci -md

Update should work at least with clean working directory:

  $ rm -r a b d
  $ hg up -r 0
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ hg st --all
  C a
  C b/b

  $ rm -r a b
  $ hg up -r 1
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ hg st --all
  C a/a
  C b