view tests/test-histedit-drop.t @ 33807:b70029f355a3

tests: verify that peer instances only expose interface members

Our abstract interfaces are more useful if we guarantee that
implementations conform to certain rules. Namely, we want to ensure
that objects implementing interfaces don't expose new public
attributes that aren't part of the interface. That way, as long as
consumers don't access "internal" attributes (those beginning with
"_") then (in theory) objects implementing interfaces can be swapped
out and everything will "just work."

We add a test that enforces our "no public attributes not part
of the abstract interface" rule.

We /could/ implement "interface compliance detection" at run-time.
However, that is littered with problems.

The obvious solutions are custom __new__ and __init__ methods.
These rely on derived types actually calling the parent's
implementation, which is no sure bet. Furthermore, __new__ and
__init__ will likely be called before instance-specific attributes
are assigned. In other words, they won't detect public attributes
set on self.__dict__. This means public attribute detection won't
be robust.

We could work around lack of robust self.__dict__ public attribute
detection by having our interfaces implement a custom __getattribute__,
__getattr__, and/or __setattr__. However, this incurs an undesirable
run-time penalty. And, subclasses could override our custom
method, bypassing the check.

The most robust solution is a non-runtime test. So that's what this
commit implements. We have a generic function for validating that an
object only has public attributes defined by abstract classes. Then,
we instantiate some peers and verify a newly constructed object
plays by the rules.

Differential Revision: https://phab.mercurial-scm.org/D339

  $ . "$TESTDIR/histedit-helpers.sh"

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > histedit=
  > EOF

  $ initrepo ()
  > {
  >     hg init r
  >     cd r
  >     for x in a b c d e f ; do
  >         echo $x > $x
  >         hg add $x
  >         hg ci -m $x
  >     done
  > }

  $ initrepo

log before edit
  $ hg log --graph
  @  changeset:   5:652413bf663e
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     f
  |
  o  changeset:   4:e860deea161a
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     e
  |
  o  changeset:   3:055a42cdd887
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     d
  |
  o  changeset:   2:177f92b77385
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     c
  |
  o  changeset:   1:d2ae7f538514
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     b
  |
  o  changeset:   0:cb9a9f314b8b
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     a
  

edit the history
  $ hg histedit 177f92b77385 --commands - 2>&1 << EOF | fixbundle
  > drop 177f92b77385 c
  > pick e860deea161a e
  > pick 652413bf663e f
  > pick 055a42cdd887 d
  > EOF

log after edit
  $ hg log --graph
  @  changeset:   4:f518305ce889
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     d
  |
  o  changeset:   3:a4f7421b80f7
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     f
  |
  o  changeset:   2:ee283cb5f2d5
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     e
  |
  o  changeset:   1:d2ae7f538514
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     b
  |
  o  changeset:   0:cb9a9f314b8b
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     a
  

Check histedit_source

  $ hg log --debug --rev f518305ce889
  changeset:   4:f518305ce889c07cb5bd05522176d75590ef3324
  tag:         tip
  phase:       draft
  parent:      3:a4f7421b80f79fcc59fff01bcbf4a53d127dd6d3
  parent:      -1:0000000000000000000000000000000000000000
  manifest:    4:d3d4f51c157ff242c32ff745d4799aaa26ccda44
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files+:      d
  extra:       branch=default
  extra:       histedit_source=055a42cdd88768532f9cf79daa407fc8d138de9b
  description:
  d
  
  

manifest after edit
  $ hg manifest
  a
  b
  d
  e
  f

Drop the last changeset

  $ hg histedit ee283cb5f2d5 --commands - 2>&1 << EOF | fixbundle
  > pick ee283cb5f2d5 e
  > pick a4f7421b80f7 f
  > drop f518305ce889 d
  > EOF
  $ hg log --graph
  @  changeset:   3:a4f7421b80f7
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     f
  |
  o  changeset:   2:ee283cb5f2d5
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     e
  |
  o  changeset:   1:d2ae7f538514
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     b
  |
  o  changeset:   0:cb9a9f314b8b
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     a
  

  $ hg histedit cb9a9f314b8b --commands - 2>&1 << EOF | fixbundle
  > pick cb9a9f314b8b a
  > pick ee283cb5f2d5 e
  > EOF
  hg: parse error: missing rules for changeset a4f7421b80f7
  (use "drop a4f7421b80f7" to discard, see also: 'hg help -e histedit.config')
  $ hg --config histedit.dropmissing=True histedit  cb9a9f314b8b --commands - 2>&1 << EOF | fixbundle
  > EOF
  hg: parse error: no rules provided
  (use strip extension to remove commits)
  $ hg --config histedit.dropmissing=True histedit  cb9a9f314b8b --commands - 2>&1 << EOF | fixbundle
  > pick cb9a9f314b8b a
  > pick ee283cb5f2d5 e
  > EOF
  $ hg log --graph
  @  changeset:   1:e99c679bf03e
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     e
  |
  o  changeset:   0:cb9a9f314b8b
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     a