Current status:
Working on using the S4-controlled recursion methods to implement s4 checkout,
switch, and update.  The viewspec module will build a tree structure to describe
the tree it wants, then a later step will read the tree and implement it.

I made a new s4 test that tries to hit more of the interesting cases if switches at
top level vs. subdirs, switches under switches, etc. That is the "view3" test in s4,
which exposed some new bugs.



- BUG: When a directory is in the repository, and it is no longer a
  switchpoint, it must not be removed!  It should be switched back to normal
  instead.


- Should I make any attempt to make unviewed directories complete evaporate?
  I think not.  If they are unviewed, it is perfectly adequate to put a
  switchpoint to void there.  And with the anti-flipflop behavior, that means
  we won't spend any time checking out the contents.

Good progress on recursing. It recurses!

Files in some directories never get checked out.  If the view contains a directory VA,
and there is a switchpoint VA/VB underneath it, the files in the directory VA are never
checked out!

But I need to teach it how to not run so many little svn commands
that it takes forever.

Q: If user makes a switchpoint in addition to the ones that s4 makes, should
I take care to always leave it alone?  Presently, no, the recurse functions
makes the switches match the viewspec, whether or not it should.

I am interested in making a tree-shaped data structure instead of a list.
This will help me to figure out if I can do an update at the top, or
a bunch of separate nonrecursive ones.  But I need to checkin before
embarking on that project.

Most s4 tests are passing, except for these.
FAIL:  s4_tests.py 4: viewspec with rev NUM feature
FAIL:  s4_tests.py 5: checkout view2 with with view lines reversed



When a deep switchpoint disappears, it no longer removes the intermediate stages.
s4: Remove unused switchpoint X/Y/Z/G

- bug:
  1. s4 co out a tree that has hw pointing to hw, and hw/ice9a pointing to void.
  2. Change viewspec so that hw/ice9a is no longer mentioned.
  3. s4 update
  Really, s4 should change hw/ice9a to hw/ice9a, but instead it leaves it as void.

- potential bug:
  Whenever pieces of S4 call other pieces of S4, there is the danger
  that $self->{revision} might get set more than once, if a checkin completes
  during the execution of S4.  To avoid this, make this into a sort of atomic
  operation, e.g. $self->default_revision() which calls which_rev() only the
  first time, and then caches the result for all subsequent times.

- s4 snap does not handle files made by "svn mv" or "svn cp" files.
  It just runs svn diff and stores their diff.
  It does not notice that they have been added and came from some other place
  in the tree.

- ViewSpec.pm: svn cat $fn does not have -rREV

- BUG: When s4 sees a command with "-r HEAD", it must sample the rev number of HEAD
  exactly one time, and afterward use that revision number only.  If we're doing
  anything more involved than a single fallback command, we must do $rev=which_rev()
  and be careful to use it everywhere.

  This is the svn_unknowns bug.


- svn diff in an area full of switches does not always traverse the switches.
  I think you see modified files, but what about svn diff -r12345.
  To make a diff of a tree with switches, I ended up with a nasty script
      svn diff -N -r27893
      dirs=$(find . -maxdepth 1 -type d | grep -v .svn | grep -v '^\.$')
      svn diff -r27893 ${dirs}



To do:
- BUG: checking the .svn/format file after creating a switchpoint:
  needs NFS existence check in there somewhere.
- (IN PROGRESS, see patch.arg-parsing-nov-02)
  It's nearly impossible s4 operations to call other s4 operations inside perl,
  For example, in scrub I want to call update.  But it should be s4 update, not
  svn update.
  To fix this, make s4 pass all the %opts into S4::update().
  Make S4::update create the raw svn command based on reading %opts.
  Then in S4::update it never needs to call main::cmd_svn().
  But with %opts the way it is, I can't do that.  %opts does not tell you
  the order that things appeared on the command line.  In some commands like
  svn copy SRC DST, the order of opts is critical.
- s4 scrub blows away switches, even the ones created by s4 checkout.
  But when it's modified to not blow away switches, it does not produce a pristine
  tree anymore!


- s4 snap cannot recreate trees with manufactured switchpoints.
  But if I make it run "s4 switch" and do the next item on my to-do list, then it can.
- svn switch URL PATH should work even if PATH doesn't exist.
  We know how to do that. :)
- Integrate rsvn
- svn switch between views should parse the viewspec, etc.  Then maybe people
  can migrate their old trees to a s4 view cleanly (?)
- Try to checkout/update/switch in a way that never checks out anything that you didn't
  ask for.  Right now, switches underneath switches cause this.
  Recurse through subdirs until you reach a point where there are no switches
  underneath.
  - (DONE) Wilson improved this already. Now it should only need to redo switches
    if the viewspec changes.
  - Checkout algorithm is...?
    - parse viewspec
    - start at the top
    - if any switchpoints below this directory, then
      - svn up -N directory
      - svn ls to find list of directories
      - for each one, recurse.
    - if no switchpoints below this directory, then
      - svn up directory (recursive)
- svn revert that changes Project.viewspec. Should we parse it?
- some stuff in Viewspec.pm should really by in S4::ViewSpec package, not main S4 package.
- Figure out the correct rules for when we can do a normal update, versus a
  multipart viewspec update.  E.g.
  - if viewspec file does not exist in directory, normal update
  - if after the update -N, the viewspec has disappeared, do what?? Presently: normal update
  - if viewspec is same as last time we did checkout/update, and the target rev
    for every part of of tree is the same, normal update
  - otherwise do multipart viewspec update
- Once I really understand the correct update and checkout logic, there is a lot
  of common code that could be combined into functions or something.
- BUG: In general, we don't allow cmdline options to appear before the svn command.
  Except Bryce added an exception for --message to make svn's regressions pass.
  This can be fixed by using a simple getopt for every single option, stuffing them
  all in a hash, and then changing SVN::S4::Getopt.pm to check that all options are
  legal--instead of what it does now.
- in viewspec file, remove "date" keyword, act the same as "rev"
- cosmetic: s4 help add prints "=head2 add"
- protect against error cases in viewspecs files
  - (DONE) bad url
  - (DONE) bad command
  - target directory with absolute path!?
  - include of nonexistent file or URL
  - (DONE) target directory several levels down without parent
- Add a test to subversion regressions that does an update of a filename that
  does not exist and submit it.  This provoked a bug in s4, and it is apparently not
  tested.
- (DONE) Measure svn rev of HEAD and use that constant instead of HEAD, so that
  all updates go to the same rev.
- (DONE) Document viewspec format
- (DONE) Include should understand URL
- (OH WELL) SVN::S4::is_file_in_repo uses system instead of SVN::Client because I could not make
  the error message disappear.
- (DONE) use rsvn everywhere, work around the problems (e.g. file not appearing for 7 seconds)
  - (DONE) remove stupid hack
    if ($s4->{svn_binary} eq 'rsvn') { push @local_svn, "--local"; }
    checkout of area with viewspec is a test case
- (DONE) move guts of checkout/update into module
- (DONE) remove chdir and pwd and make it work again
  - it should not depend on current directory
- (DONE) move all s4 global variables to SVN::S4
- (DONE) BUG: from top directory, cd.. and then s4 update DIRNAME. It starts checking things
  out in the current dir, not the target dir.
- (DONE) all new commands should check for unknown options
- (DONE) remove any s4 dependency on SCX environment variables
- (DONE) BUG mys4 checkout URL PATH is broken.
- (DONE) change file_url back
- (DONE) how to support -rREV.  I thought
  Getopt::Long::config("bundling_override")
  would do it, but it doesn't.
  Example: s4 up -r26784        #FAILS
  Example: s4 up -r 26784       #WORKS
- (DONE) "s4 up viewpass1" is fine, but "s4 up viewpass1/" fails
  perl: subversion/libsvn_subr/path.c:113: svn_path_join: Assertion `is_canonical (base, blen)' failed.
- (DONE) BUG ./update_tests.py 15     (but passes without s4 wrapper)
    EXPECTED STDOUT:
    D  working_copies/update_tests-15/A/D/G
    Updated to revision 3.
    ACTUAL STDOUT:
    EXCEPTION: SVNLineUnequal
    FAIL:  update_tests.py 15: another "hudson" problem: updates that delete
  - solution:
    - (DONE) add a check to S4::rev_on_date.
    - (DONE) make which_rev only get called in viewspec mode
- (DONE) BUG:
  "s4 up -rREV" fails
  "s4 up -r REV" is okay
- (FIXED) BUG ./update_tests.py 22 fails  (but passes without s4 wrapper)
  Unequal Types: one Node is a file, the other is a directory
  EXCEPTION: SVNTreeUnequal
  FAIL:  update_tests.py 22: update target that was added in a future rev
- (DONE) BUG: unview caused a crash, unless you later replaced the exact path with
  a new view command.  Fixed in 27071.
- (DONE) performance improvement: with viewspecs, test if a single svn update
  will suffice.  If so, it can be much faster!
  - Md5sum of the viewspec actions list, except for the revision number.
    If the md5sum matches the last completed update or checkout, and all the
    target revision numbers in the whole tree are identical, do a single update
    at the top of tree.
- (DONE) set command should set some internal hash, not the real environment variables,
  or you may be able to do nasty things
- (DONE) make this use SVN::Client: is_file_in_repo
- write regression tests for viewspec behavior
  - (DONE) checkout with viewspec
  - (DONE) update when viewspec changes
  - (DONE) test all viewspec syntax
  - you can always write more tests
- (FIXED) BUG: svn checkout -r does not obey the -r in the top level checkout
- (DONE) @list_actions should not need to be in order. just sort by target dir, and the
  order no longer matters.  Add s4_test called "s4_checkout_view2_viewlines_out_of_order"
  to regress this.
- (DONE) Undo switches when the view line is removed from viewspec.
  Store the previous parsed viewspec somewhere, and compare them so that we
  can tell what switches should be switched back.
- (DONE) document new update and checkout behavior
- (DONE) OUCH! newer svns do not allow the "switch --relocate" trick.
  So dammit I'm going to edit the .svn/entries file myself.  It's actually much easier
  than the switch relocate trick anyway.
    Make a versioned directory called A.
    Just add the line:
       <entry name="A" kind="dir"/>
    and then you can svn switch A to anything you want.
    If you don't switch it, the next update will make A get deleted.
- (DONE) BUG: "s4 --version" fails
  s4 --version   #fail
  svn --version  #ok
- (DONE) BUG: we don't allow cmdline options to appear before the svn command.
  "s4 -m message commit file" fails
  "s4 commit -m message file" ok
  "s4 commit file -m message" ok
- (DONE) when view line gives bad URL, very confusing errors result.
  Just before doing svn switch, take the time to check if it's in the repository.
- (DONE) BUG: Undoing switchpoints does the wrong thing if there are switchpoints underneath other
  switchpoints.
  mys4 up -r11; mys4 up -r12
  cd /local/denney/svn114branch/subversion/tests/clients/cmdline/working_copies/s4_tests-7.wc2
  It is ok to be over conservative (e.g. never remove any switchpoints)
  but it is not okay to make things disappear when they should not.
- (DONE) BUG: s4 does not undo void switchpoints that were created on the way to a real switchpoint.
  Really it should.
- (DONE) What happens if two view lines map the same switchpoint? Illegal, or one overrides the other?
  Now, one overrides the other.
- (DONE) if the URL is outside of the repository:
  - (DONE) test UUID
  - (DONE) print an error that it's not supported
  - or, make an svn external (svn propset . and then svn co [-r] URL PATH)
    but wait until there's a need.
- (DONE) Integrate complete_patch as "s4 snapshot"
- (DONE) Integrate strong_revert as "s4 revert --force"



To decide:
- How to make a tag when the view is an important part of the tag?
  svn cp trunk tags/1.1
  Then you can check out the tag of trunk and you know that it's static.
  Then if you want any views to point to the tag, you svn cp the view, edit the
  Project.viewspec so that the URLs are different, and check in the view.

  trunk
  tags
    1.1
    1.2
    1.3
  views/
    viewpass1/
      Project.viewspec
    viewpep/
      Project.viewspec
  branches
    1.1.1


- s4 update simh_2006-07-01 would ideally update that directory with knowledge
  of what the viewspec says.  But in our current model, since you did not update
  from the top, the viewspec would never be considered.  That seems bad.
- what does checkout/update do with multiple arguments?  What if one of them points
  to a directory with a viewspec but others don't?
  Wilson suggests: if multiple files and one has a viewspec, crash. Force user to
  do one at a time.
- how much to display during the viewspec update?
  - (DONE) hide any implicit commits to voids area (/dev/null)
- try to use SVN::Client everywhere, or build svn commands and call system?
- (DONE) how to specify URL of voids, so that tool is not specific to our repository?
  Maybe it can find the top of repo, then add "/s4voids/NAME".
  Walk up tree, require user to create it.
- Where to store state? I thought something like $HOME/.s4/viewspec_state
  and then name file based on `/bin/pwd|md5sum` so that working areas don't get
  confused.   If it's in the working area itself, you have to change properties
  to ignore it.
  A: Use .svn/s4
- How to handle "s4 update -r 20000", when the whole view area did not exist at the time?
  One way is to use the Project.viewspec for everything.
  Another way is to somehow request that the view stay at HEAD or whatever, while
  the -r20000 affects only the switched areas. Hmm.
  A:  Have a option that doesn't update the top of the tree --noupdatetop


Testing s4:
- how to build test environment:
  wget http://subversion.tigris.org/tarballs/subversion-1.1.4.tar.gz
  svn co svn+ssh://svn.sicortex.com/svn/master/software/devel/subversion/branches/denney_s4_tests
  cd denney_s4_tests
  ./configure LDFLAGS=-L/usr/lib64
  make
  cd subversion/tests/clients/cmdline
  cp ../../../../test_bryce_s4_with_svn114 .
  vi test_bryce_s4_with_svn114
  # fix S4TOP to point to this area
  vi svntest/main.py
  # comment out line 93 and replace with
  #   svn_binary = os.path.abspath('test_bryce_s4_with_svn114' + _exe)
  ssh srv003   # this machine has random number generation problem fixed
  cd to ..../subversion/tests/clients/cmdline
  ./basic_tests.py 1
  # if it works, you did all these steps right.
- to run regressions, do ./run_svn_regressions

-  from the svn book http://svnbook.red-bean.com/nightly/en/svn.ref.html#svn.ref.svn
    To use the command line client, you type svn, the subcommand you wish to
    use [49], and any switches or targets that you wish to operate on—there is no
    specific order that the subcommand and the switches must appear in. For
    example, all of the following are valid ways to use svn status:
    $ svn -v status
    $ svn status -v
    $ svn status -v myfile

- test with svn 1.2.3. on suse10
