view tests/test-narrow-expanddirstate.t @ 42619:20d0e59be79b

tests: show the files fields of changelogs for many merges

I don't think there's coverage for many of the subtle cases, and I
found it hard to understand what the code is doing by reading it.  The
test takes 40s to run on a laptop, or 9s with --chg.

I have yet to find a description of what the files field is supposed
to be for merges. I thought it could be one of:
1. the files added/modified/removed relative to p1 (wouldn't seem
  useful, but `hg diff -c -r mergerev` has this behavior)
2. the files with filelog nodes not in either parent (i.e., what is
needed to create a bundle out of a commit)
3. the files added/removed/modified files by merge itself [1]

It's clearly not 1, because file contents merges are symmetric. It's
clearly not 2 because removed files and exec bit changes are
listed. It's also not 3 but I think it's intended to be 3 and the
differences are bugs.

Assuming 3, the test shows that, for merges, the list of files both
overapproximates and underapproximates. All the cases involve file
changes not in the filelog but in the manifest (existence of file
at revision, exec bit and file vs symlink).

I didn't look at all underapproximations, but they looked minor. The
two overapproximations are problematic though because they both cause
potentially long lists of files when merging cleanly.


[1] even what it means for the merge commit itself to change a file is
not completely trivial. A file in the merge being the same as in one
of the parent is too lax as it would consider that merges change
nothing when they revert all the changes done on one side. The
criteria used in the test and in the next commit for "merge didn't
touch a file" is:
- the parents and the merge all have the same file
- or, one parent didn't touch the file and the other parent contains
  the same file as the merge

Differential Revision: https://phab.mercurial-scm.org/D6612

  $ . "$TESTDIR/narrow-library.sh"

  $ hg init master
  $ cd master

  $ mkdir inside
  $ echo inside > inside/f1
  $ mkdir outside
  $ echo outside > outside/f2
  $ mkdir patchdir
  $ echo patch_this > patchdir/f3
  $ hg ci -Aqm 'initial'

  $ cd ..

  $ hg clone --narrow ssh://user@dummy/master narrow --include inside
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  new changesets dff6a2a6d433
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ cd narrow

  $ mkdir outside
  $ echo other_contents > outside/f2
  $ hg tracked | grep outside
  [1]
  $ hg files | grep outside
  [1]
  $ hg status

`hg status` did not add outside.
  $ hg tracked | grep outside
  [1]
  $ hg files | grep outside
  [1]

Unfortunately this is not really a candidate for adding to narrowhg proper,
since it depends on some other source for providing the manifests (when using
treemanifests) and file contents. Something like a virtual filesystem and/or
remotefilelog. We want to be useful when not using those systems, so we do not
have this method available in narrowhg proper at the moment.
  $ cat > "$TESTTMP/expand_extension.py" <<EOF
  > import os
  > import sys
  > 
  > from mercurial import encoding
  > from mercurial import extensions
  > from mercurial import localrepo
  > from mercurial import match as matchmod
  > from mercurial import narrowspec
  > from mercurial import patch
  > from mercurial import util as hgutil
  > 
  > narrowspecexpanded = False
  > def expandnarrowspec(ui, repo, newincludes=None):
  >   if not newincludes:
  >     return
  >   if getattr(repo, '_narrowspecexpanded', False):
  >     return
  >   repo._narrowspecexpanded = True
  >   import sys
  >   newincludes = set([newincludes])
  >   includes, excludes = repo.narrowpats
  >   currentmatcher = narrowspec.match(repo.root, includes, excludes)
  >   includes = includes | newincludes
  >   if not repo.currenttransaction():
  >     ui.develwarn(b'expandnarrowspec called outside of transaction!')
  >   repo.setnarrowpats(includes, excludes)
  >   narrowspec.copytoworkingcopy(repo)
  >   newmatcher = narrowspec.match(repo.root, includes, excludes)
  >   added = matchmod.differencematcher(newmatcher, currentmatcher)
  >   for f in repo[b'.'].manifest().walk(added):
  >     repo.dirstate.normallookup(f)
  > 
  > def reposetup(ui, repo):
  >   class expandingrepo(repo.__class__):
  >     def narrowmatch(self, *args, **kwargs):
  >       with repo.wlock(), repo.lock(), repo.transaction(
  >           b'expandnarrowspec'):
  >         expandnarrowspec(ui, repo,
  >                          encoding.environ.get(b'DIRSTATEINCLUDES'))
  >       return super(expandingrepo, self).narrowmatch(*args, **kwargs)
  >   repo.__class__ = expandingrepo
  > 
  > def extsetup(unused_ui):
  >   def overridepatch(orig, ui, repo, *args, **kwargs):
  >     with repo.wlock():
  >       expandnarrowspec(ui, repo, encoding.environ.get(b'PATCHINCLUDES'))
  >       return orig(ui, repo, *args, **kwargs)
  > 
  >   extensions.wrapfunction(patch, b'patch', overridepatch)
  > EOF
  $ cat >> ".hg/hgrc" <<EOF
  > [extensions]
  > expand_extension = $TESTTMP/expand_extension.py
  > EOF

Since we do not have the ability to rely on a virtual filesystem or
remotefilelog in the test, we just fake it by copying the data from the 'master'
repo.
  $ cp -a ../master/.hg/store/data/* .hg/store/data
Do that for patchdir as well.
  $ cp -a ../master/patchdir .

`hg status` will now add outside, but not patchdir.
  $ DIRSTATEINCLUDES=path:outside hg status
  M outside/f2
  $ hg tracked | grep outside
  I path:outside
  $ hg files | grep outside > /dev/null
  $ hg tracked | grep patchdir
  [1]
  $ hg files | grep patchdir
  [1]

Get rid of the modification to outside/f2.
  $ hg update -C .
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

This patch will not apply cleanly at the moment, so `hg import` will break
  $ cat > "$TESTTMP/foo.patch" <<EOF
  > --- patchdir/f3
  > +++ patchdir/f3
  > @@ -1,1 +1,1 @@
  > -this should be "patch_this", but its not, so patch fails
  > +this text is irrelevant
  > EOF
  $ PATCHINCLUDES=path:patchdir hg import -p0 -e "$TESTTMP/foo.patch" -m ignored
  applying $TESTTMP/foo.patch
  patching file patchdir/f3
  Hunk #1 FAILED at 0
  1 out of 1 hunks FAILED -- saving rejects to file patchdir/f3.rej
  abort: patch failed to apply
  [255]
  $ hg tracked | grep patchdir
  [1]
  $ hg files | grep patchdir > /dev/null
  [1]

Let's make it apply cleanly and see that it *did* expand properly
  $ cat > "$TESTTMP/foo.patch" <<EOF
  > --- patchdir/f3
  > +++ patchdir/f3
  > @@ -1,1 +1,1 @@
  > -patch_this
  > +patched_this
  > EOF
  $ PATCHINCLUDES=path:patchdir hg import -p0 -e "$TESTTMP/foo.patch" -m message
  applying $TESTTMP/foo.patch
  $ cat patchdir/f3
  patched_this
  $ hg tracked | grep patchdir
  I path:patchdir
  $ hg files | grep patchdir > /dev/null