tests/test-hgwebdirsym.t

copies: filter out copies from non-existent source later in _chain()

_changesetforwardcopies() repeatedly calls _chain(). That is very
expensive because _chain() does lookups in the manifest. I hope to
split up the function in two parts: 1) simple chaining, not
considering end points, and 2) filter out files that don't exist in
the end points (and ping-pong copies/renames).

This patches gets us closer to that by moving the check for
non-existent source later in the function. Now there are no more
checks for "src" and "dst" in the first loop; all the filtering of
invalid copies is done in the second loop. The code also looks much
more consistent now.

No measureable impact on `hg debugpathcopies 4.0 4.8`. That shouldn't
be surprising since the only case we're doing more checks now is in
case of chained copies/renames, which are quire rare in practice.

Differential Revision: https://phab.mercurial-scm.org/D6277

#require serve symlink

Tests whether or not hgwebdir properly handles various symlink topologies.

hide outer repo
  $ hg init

  $ hg init a
  $ echo a > a/a
  $ hg --cwd a ci -Ama -d'1 0'
  adding a
  $ mkdir webdir
  $ cd webdir
  $ hg init b
  $ echo b > b/b
  $ hg --cwd b ci -Amb -d'2 0'
  adding b
  $ hg init c
  $ echo c > c/c
  $ hg --cwd c ci -Amc -d'3 0'
  adding c
  $ ln -s ../a al
  $ ln -s ../webdir circle
  $ root=`pwd`
  $ cd ..
  $ cat > collections.conf <<EOF
  > [collections]
  > $root=$root
  > EOF
  $ hg serve -p $HGPORT -d --pid-file=hg.pid --webdir-conf collections.conf \
  >     -A access-collections.log -E error-collections.log
  $ cat hg.pid >> $DAEMON_PIDS

should succeed

  $ get-with-headers.py localhost:$HGPORT '?style=raw'
  200 Script output follows
  
  
  /al/
  /b/
  /c/
  
  $ get-with-headers.py localhost:$HGPORT 'al/file/tip/a?style=raw'
  200 Script output follows
  
  a
  $ get-with-headers.py localhost:$HGPORT 'b/file/tip/b?style=raw'
  200 Script output follows
  
  b
  $ get-with-headers.py localhost:$HGPORT 'c/file/tip/c?style=raw'
  200 Script output follows
  
  c

should fail

  $ get-with-headers.py localhost:$HGPORT 'circle/al/file/tip/a?style=raw'
  404 Not Found
  
  
  error: repository circle/al/file/tip/a not found
  [1]
  $ get-with-headers.py localhost:$HGPORT 'circle/b/file/tip/a?style=raw'
  404 Not Found
  
  
  error: repository circle/b/file/tip/a not found
  [1]
  $ get-with-headers.py localhost:$HGPORT 'circle/c/file/tip/a?style=raw'
  404 Not Found
  
  
  error: repository circle/c/file/tip/a not found
  [1]

collections errors

  $ cat error-collections.log