tests/test-diff-hashes.t

hgweb: show as same parents as "hg parents -r REV FILE" in pages for file

Before this patch, "parents" in pages for file doesn't show as same
parents as "hg parents -r REV FILE", when the specified file is not
modified in the specified revision.

For example, it is assumed that revision A, B and D change file "f".

    changelog   (A) ---> (B) ---> (C) ---> (D)
    filelog "f" (x) ---> (y) ------------> (z)

"/file/D/f" invokes "webutil.parents()" with filectx(z) gotten from
changectx(D), and it returns changectx(B). This is as same result as
"hg parents -r D f".

In the other hand, "/file/C/f" invokes "webutil.parents()" with
filectx(y') gotten from changectx(C), and it returns changectx(A),
because filectx(y') is linked to changectx(B), and works like
filectx(y) in some cases.

In this case, revision B is hidden from users browsing file "f" in
revision C.

This patch shows as same parents as "hg parents -r REV FILE" in pages
for file, by making "webutil.parents()" return:

  - "linkrev()"-ed revision only, if:

    - specified context instance is "filectx" (because
      "webutil.parents()" is invoked with changectx, too), and

    - (1) the revision from which filectx is gotten and (2) the one to
      which filectx is linked are different from each other

  - revision gotten from "ctx.parents()", otherwise

  $ hg init a
  $ cd a

  $ hg diff inexistent1 inexistent2
  inexistent1: * (glob)
  inexistent2: * (glob)

  $ echo bar > foo
  $ hg add foo
  $ hg ci -m 'add foo'

  $ echo foobar > foo
  $ hg ci -m 'change foo'

  $ hg --quiet diff -r 0 -r 1
  --- a/foo	Thu Jan 01 00:00:00 1970 +0000
  +++ b/foo	Thu Jan 01 00:00:00 1970 +0000
  @@ -1,1 +1,1 @@
  -bar
  +foobar

  $ hg diff -r 0 -r 1
  diff -r a99fb63adac3 -r 9b8568d3af2f foo
  --- a/foo	Thu Jan 01 00:00:00 1970 +0000
  +++ b/foo	Thu Jan 01 00:00:00 1970 +0000
  @@ -1,1 +1,1 @@
  -bar
  +foobar

  $ hg --verbose diff -r 0 -r 1
  diff -r a99fb63adac3 -r 9b8568d3af2f foo
  --- a/foo	Thu Jan 01 00:00:00 1970 +0000
  +++ b/foo	Thu Jan 01 00:00:00 1970 +0000
  @@ -1,1 +1,1 @@
  -bar
  +foobar

  $ hg --debug diff -r 0 -r 1
  diff -r a99fb63adac3f31816a22f665bc3b7a7655b30f4 -r 9b8568d3af2f1749445eef03aede868a6f39f210 foo
  --- a/foo	Thu Jan 01 00:00:00 1970 +0000
  +++ b/foo	Thu Jan 01 00:00:00 1970 +0000
  @@ -1,1 +1,1 @@
  -bar
  +foobar

  $ cd ..