view tests/test-removeemptydirs.t @ 39764:e4e881572382

localrepo: iteratively derive local repository type

This commit implements the dynamic local repository type derivation
that was explained in the recent commit
bfeab472e3c0 "localrepo: create new function for instantiating a local
repo object."

Instead of a static localrepository class/type which must be customized
after construction, we now dynamically construct a type by building up
base classes/types to represent specific repository interfaces.

Conceptually, the end state is similar to what was happening when
various extensions would monkeypatch the __class__ of newly-constructed
repo instances. However, the approach is inverted. Instead of making
the instance then customizing it, we do the customization up front
by influencing the behavior of the type then we instantiate that
custom type.

This approach gives us much more flexibility. For example, we can
use completely separate classes for implementing different aspects
of the repository. For example, we could have one class representing
revlog-based file storage and another representing non-revlog based
file storage. When then choose which implementation to use based on
the presence of repo requirements.

A concern with this approach is that it creates a lot more types
and complexity and that complexity adds overhead. Yes, it is true that
this approach will result in more types being created. Yes, this is
more complicated than traditional "instantiate a static type." However,
I believe the alternatives to supporting alternate storage backends
are just as complicated. (Before I arrived at this solution, I had
patches storing factory functions on local repo instances for e.g.
constructing a file storage instance. We ended up having a handful
of these. And this was logically identical to assigning custom
methods. Since we were logically changing the type of the instance,
I figured it would be better to just use specialized types instead
of introducing levels of abstraction at run-time.)

On the performance front, I don't believe that having N base classes
has any significant performance overhead compared to just a single base
class. Intuition says that Python will need to iterate the base classes
to find an attribute. However, CPython caches method lookups: as long as
the __class__ or MRO isn't changing, method attribute lookup should be
constant time after first access. And non-method attributes are stored
in __dict__, of which there is only 1 per object, so the number of
base classes for __dict__ is irrelevant.

Anyway, this commit splits up the monolithic completelocalrepository
interface into sub-interfaces: 1 for file storage and 1 representing
everything else.

We've taught ``makelocalrepository()`` to call a series of factory
functions which will produce types implementing specific interfaces.
It then calls type() to create a new type from the built-up list of
base types.

This commit should be considered a start and not the end state. I
suspect we'll hit a number of problems as we start to implement
alternate storage backends:

* Passing custom arguments to __init__ and setting custom attributes
  on __dict__.
* Customizing the set of interfaces that are needed. e.g. the
  "readonly" intent could translate to not requesting an interface
  providing methods related to writing.
* More ergonomic way for extensions to insert themselves so their
  callbacks aren't unconditionally called.
* Wanting to modify vfs instances, other arguments passed to __init__.

That being said, this code is usable in its current state and I'm
convinced future commits will demonstrate the value in this approach.

Differential Revision: https://phab.mercurial-scm.org/D4642

Tests for experimental.removeemptydirs

  $ NO_RM=--config=experimental.removeemptydirs=0
  $ isdir() { if [ -d $1 ]; then echo yes; else echo no; fi }
  $ isfile() { if [ -f $1 ]; then echo yes; else echo no; fi }

`hg rm` of the last file in a directory:
  $ hg init hgrm
  $ cd hgrm
  $ mkdir somedir
  $ echo hi > somedir/foo
  $ hg ci -qAm foo
  $ isdir somedir
  yes
  $ hg rm somedir/foo
  $ isdir somedir
  no
  $ hg revert -qa
  $ isdir somedir
  yes
  $ hg $NO_RM rm somedir/foo
  $ isdir somedir
  yes
  $ ls somedir
  $ cd $TESTTMP

`hg mv` of the last file in a directory:
  $ hg init hgmv
  $ cd hgmv
  $ mkdir somedir
  $ mkdir destdir
  $ echo hi > somedir/foo
  $ hg ci -qAm foo
  $ isdir somedir
  yes
  $ hg mv somedir/foo destdir/foo
  $ isdir somedir
  no
  $ hg revert -qa
(revert doesn't get rid of destdir/foo?)
  $ rm destdir/foo
  $ isdir somedir
  yes
  $ hg $NO_RM mv somedir/foo destdir/foo
  $ isdir somedir
  yes
  $ ls somedir
  $ cd $TESTTMP

Updating to a commit that doesn't have the directory:
  $ hg init hgupdate
  $ cd hgupdate
  $ echo hi > r0
  $ hg ci -qAm r0
  $ mkdir somedir
  $ echo hi > somedir/foo
  $ hg ci -qAm r1
  $ isdir somedir
  yes
  $ hg co -q -r ".^"
  $ isdir somedir
  no
  $ hg co -q tip
  $ isdir somedir
  yes
  $ hg $NO_RM co -q -r ".^"
  $ isdir somedir
  yes
  $ ls somedir
  $ cd $TESTTMP

Rebasing across a commit that doesn't have the directory, from inside the
directory:
  $ hg init hgrebase
  $ cd hgrebase
  $ echo hi > r0
  $ hg ci -qAm r0
  $ mkdir somedir
  $ echo hi > somedir/foo
  $ hg ci -qAm first_rebase_source
  $ hg $NO_RM co -q -r ".^"
  $ echo hi > somedir/bar
  $ hg ci -qAm first_rebase_dest
  $ hg $NO_RM co -q -r ".^"
  $ echo hi > somedir/baz
  $ hg ci -qAm second_rebase_dest
  $ hg co -qr 'desc(first_rebase_source)'
  $ cd $TESTTMP/hgrebase/somedir
  $ hg --config extensions.rebase= rebase -qr . -d 'desc(first_rebase_dest)'
  current directory was removed (rmcwd !)
  (consider changing to repo root: $TESTTMP/hgrebase) (rmcwd !)
  $ cd $TESTTMP/hgrebase/somedir
(The current node is the rebased first_rebase_source on top of
first_rebase_dest)
This should not output anything about current directory being removed:
  $ hg $NO_RM --config extensions.rebase= rebase -qr . -d 'desc(second_rebase_dest)'
  $ cd $TESTTMP

Histediting across a commit that doesn't have the directory, from inside the
directory (reordering nodes):
  $ hg init hghistedit
  $ cd hghistedit
  $ echo hi > r0
  $ hg ci -qAm r0
  $ echo hi > r1
  $ hg ci -qAm r1
  $ echo hi > r2
  $ hg ci -qAm r2
  $ mkdir somedir
  $ echo hi > somedir/foo
  $ hg ci -qAm migrating_revision
  $ cat > histedit_commands <<EOF
  > pick 89079fab8aee 0 r0
  > pick e6d271df3142 1 r1
  > pick 89e25aa83f0f 3 migrating_revision
  > pick b550aa12d873 2 r2
  > EOF
  $ cd $TESTTMP/hghistedit/somedir
  $ hg --config extensions.histedit= histedit -q --commands ../histedit_commands

histedit doesn't output anything when the current diretory is removed. We rely
on the tests being commonly run on machines where the current directory
disappearing from underneath us actually has an observable effect, such as an
error or no files listed
#if linuxormacos
  $ isfile foo
  no
#endif
  $ cd $TESTTMP/hghistedit/somedir
  $ isfile foo
  yes

  $ cd $TESTTMP/hghistedit
  $ cat > histedit_commands <<EOF
  > pick 89079fab8aee 0 r0
  > pick 7c7a22c6009f 3 migrating_revision
  > pick e6d271df3142 1 r1
  > pick 40a53c2d4276 2 r2
  > EOF
  $ cd $TESTTMP/hghistedit/somedir
  $ hg $NO_RM --config extensions.histedit= histedit -q --commands ../histedit_commands
Regardless of system, we should always get a 'yes' here.
  $ isfile foo
  yes
  $ cd $TESTTMP

This is essentially the exact test from issue5826, just cleaned up a little:

  $ hg init issue5826_withrm
  $ cd issue5826_withrm

Let's only turn this on for this repo so that we don't contaminate later tests.
  $ cat >> .hg/hgrc <<EOF
  > [extensions]
  > histedit =
  > EOF
Commit three revisions that each create a directory:

  $ mkdir foo
  $ touch foo/bar
  $ hg commit -qAm "add foo"

  $ mkdir bar
  $ touch bar/bar
  $ hg commit -qAm "add bar"

  $ mkdir baz
  $ touch baz/bar
  $ hg commit -qAm "add baz"

Enter the first directory:

  $ cd foo

Histedit doing 'pick, pick, fold':

#if rmcwd

  $ hg histedit --commands - <<EOF
  > pick 6274c77c93c3 1 add bar
  > pick ff70a87b588f 0 add foo
  > fold 9992bb0ac0db 2 add baz
  > EOF
  abort: $ENOENT$
  [255]

Go back to the repo root after losing it as part of that operation:
  $ cd $TESTTMP/issue5826_withrm

Note the lack of a non-zero exit code from this function - it exits
successfully, but doesn't really do anything.
  $ hg histedit --continue
  9992bb0ac0db: cannot fold - working copy is not a descendant of previous commit 5c806432464a
  saved backup bundle to $TESTTMP/issue5826_withrm/.hg/strip-backup/ff70a87b588f-e94f9789-histedit.hg

  $ hg log -T '{rev}:{node|short} {desc}\n'
  2:94e3f9fae1d6 fold-temp-revision 9992bb0ac0db
  1:5c806432464a add foo
  0:d17db4b0303a add bar

#else

  $ cd $TESTTMP/issue5826_withrm

  $ hg histedit --commands - <<EOF
  > pick 6274c77c93c3 1 add bar
  > pick ff70a87b588f 0 add foo
  > fold 9992bb0ac0db 2 add baz
  > EOF
  saved backup bundle to $TESTTMP/issue5826_withrm/.hg/strip-backup/5c806432464a-cd4c8d86-histedit.hg

  $ hg log -T '{rev}:{node|short} {desc}\n'
  1:b9eddaa97cbc add foo
  ***
  add baz
  0:d17db4b0303a add bar

#endif

Now test that again with experimental.removeemptydirs=false:
  $ hg init issue5826_norm
  $ cd issue5826_norm

Let's only turn this on for this repo so that we don't contaminate later tests.
  $ cat >> .hg/hgrc <<EOF
  > [extensions]
  > histedit =
  > [experimental]
  > removeemptydirs = false
  > EOF
Commit three revisions that each create a directory:

  $ mkdir foo
  $ touch foo/bar
  $ hg commit -qAm "add foo"

  $ mkdir bar
  $ touch bar/bar
  $ hg commit -qAm "add bar"

  $ mkdir baz
  $ touch baz/bar
  $ hg commit -qAm "add baz"

Enter the first directory:

  $ cd foo

Histedit doing 'pick, pick, fold':

  $ hg histedit --commands - <<EOF
  > pick 6274c77c93c3 1 add bar
  > pick ff70a87b588f 0 add foo
  > fold 9992bb0ac0db 2 add baz
  > EOF
  saved backup bundle to $TESTTMP/issue5826_withrm/issue5826_norm/.hg/strip-backup/5c806432464a-cd4c8d86-histedit.hg

Note the lack of a 'cd' being necessary here, and we don't need to 'histedit
--continue'

  $ hg log -T '{rev}:{node|short} {desc}\n'
  1:b9eddaa97cbc add foo
  ***
  add baz
  0:d17db4b0303a add bar

  $ cd $TESTTMP

Testing `hg split` being run from inside of a directory that was created in the
commit being split:

  $ hg init hgsplit
  $ cd hgsplit
  $ cat >> .hg/hgrc << EOF
  > [ui]
  > interactive = 1
  > [extensions]
  > split =
  > EOF
  $ echo anchor > anchor.txt
  $ hg ci -qAm anchor

Create a changeset with '/otherfile_in_root' and 'somedir/foo', then try to
split it.
  $ echo otherfile > otherfile_in_root
  $ mkdir somedir
  $ cd somedir
  $ echo hi > foo
  $ hg ci -qAm split_me
(Note: need to make this file not in this directory, or else the bug doesn't
reproduce; we're using a separate file due to concerns of portability on
`echo -e`)
  $ cat > ../split_commands << EOF
  > n
  > y
  > y
  > a
  > EOF

The split succeeds on no-rmcwd platforms, which alters the rest of the tests
#if rmcwd
  $ cat ../split_commands | hg split
  current directory was removed
  (consider changing to repo root: $TESTTMP/hgsplit)
  diff --git a/otherfile_in_root b/otherfile_in_root
  new file mode 100644
  examine changes to 'otherfile_in_root'? [Ynesfdaq?] n
  
  diff --git a/somedir/foo b/somedir/foo
  new file mode 100644
  examine changes to 'somedir/foo'? [Ynesfdaq?] y
  
  @@ -0,0 +1,1 @@
  +hi
  record change 2/2 to 'somedir/foo'? [Ynesfdaq?] y
  
  abort: $ENOENT$
  [255]
#endif

Let's try that again without the rmdir
  $ cd $TESTTMP/hgsplit/somedir
Show that the previous split didn't do anything
  $ hg log -T '{rev}:{node|short} {desc}\n'
  1:e26b22a4f0b7 split_me
  0:7e53273730c0 anchor
  $ hg status
  ? split_commands
Try again
  $ cat ../split_commands | hg $NO_RM split
  diff --git a/otherfile_in_root b/otherfile_in_root
  new file mode 100644
  examine changes to 'otherfile_in_root'? [Ynesfdaq?] n
  
  diff --git a/somedir/foo b/somedir/foo
  new file mode 100644
  examine changes to 'somedir/foo'? [Ynesfdaq?] y
  
  @@ -0,0 +1,1 @@
  +hi
  record change 2/2 to 'somedir/foo'? [Ynesfdaq?] y
  
  created new head
  diff --git a/otherfile_in_root b/otherfile_in_root
  new file mode 100644
  examine changes to 'otherfile_in_root'? [Ynesfdaq?] a
  
  saved backup bundle to $TESTTMP/hgsplit/.hg/strip-backup/*-split.hg (glob)
Show that this split did something
  $ hg log -T '{rev}:{node|short} {desc}\n'
  2:a440f24fca4f split_me
  1:c994f20276ab split_me
  0:7e53273730c0 anchor
  $ hg status
  ? split_commands