Fix more trouble with .do scripts that cd to other directories.

The interaction of REDO_STARTDIR, REDO_PWD, and getcwd() are pretty
complicated.  In this case, we accidentally assumed that the current
instance of redo was running with getcwd() == REDO_STARTDIR+REDO_PWD, and so
the new target was REDO_STARTDIR+REDO_PWD+t, but this isn't the case if the
current .do script did chdir().

The correct answer is REDO_STARTDIR+getcwd()+t.

builder.py

@@ -95,9 +95,13 @@ class BuildJob:
         jwack.start_job(t, self._do_subproc, self._after)
 
     def _do_subproc(self):
-        td = os.environ.get('REDO_PWD', '')
+        # careful: REDO_PWD was the PWD relative to the STARTPATH at the time
+        # we *started* building the current target; but that target ran
+        # redo-ifchange, and it might have done it from a different directory
+        # than we started it in.  So os.getcwd() might be != REDO_PWD right now.
         dn = os.path.dirname(self.t)
-        os.environ['REDO_PWD'] = os.path.join(td, dn)
+        newp = os.path.realpath(dn)
+        os.environ['REDO_PWD'] = state.relpath(newp, vars.STARTDIR)
         os.environ['REDO_TARGET'] = os.path.basename(self.t)
         os.environ['REDO_DEPTH'] = vars.DEPTH + '  '
         if dn:

helpers.py

@@ -67,6 +67,9 @@ def debug(s):
 def debug2(s):
     if vars.DEBUG >= 2:
         log_('redo: %s%s' % (vars.DEPTH, s))
+def debug3(s):
+    if vars.DEBUG >= 3:
+        log_('redo: %s%s' % (vars.DEPTH, s))
 
 
 def close_on_exec(fd, yes):

redo-ifchange.py

@@ -1,7 +1,7 @@
 #!/usr/bin/python
 import sys, os, errno
 import vars, state, builder, jwack
-from helpers import debug, err, mkdirp, unlink
+from helpers import debug, debug2, err, mkdirp, unlink
 
 
 def dirty_deps(t, depth):
@@ -49,12 +49,13 @@ def should_build(t):
 
 rv = 202
 try:
+    me = os.path.join(vars.STARTDIR, 
+                      os.path.join(vars.PWD, vars.TARGET))
+    debug2('TARGET: %r %r %r\n' % (vars.STARTDIR, vars.PWD, vars.TARGET))
     try:
         targets = sys.argv[1:]
         for t in targets:
-            state.add_dep(os.path.join(vars.STARTDIR, 
-                                       os.path.join(vars.PWD, vars.TARGET)),
-                          'm', t)
+            state.add_dep(me, 'm', t)
         rv = builder.main(targets, should_build)
     finally:
         jwack.force_return_tokens()

state.py

@@ -1,6 +1,6 @@
 import sys, os, errno, glob
 import vars
-from helpers import unlink, err, debug2, mkdirp, close_on_exec
+from helpers import unlink, err, debug2, debug3, mkdirp, close_on_exec
 
 
 def init():
@@ -50,15 +50,17 @@ def _sname(typ, t):
     # FIXME: t.replace(...) is non-reversible and non-unique here!
     tnew = relpath(t, vars.BASE)
     v = vars.BASE + ('/.redo/%s^%s' % (typ, tnew.replace('/', '^')))
-    if vars.DEBUG >= 2:
-        debug2('sname: (%r) %r -> %r\n' % (os.getcwd(), t, tnew))
+    if vars.DEBUG >= 3:
+        debug3('sname: (%r) %r -> %r\n' % (os.getcwd(), t, tnew))
     return v
 
 
 def add_dep(t, mode, dep):
-    debug2('add-dep(%r)\n' % t)
-    open(_sname('dep', t), 'a').write('%s %s\n'
-                                      % (mode, relpath(dep, vars.BASE)))
+    sn = _sname('dep', t)
+    reldep = relpath(dep, vars.BASE)
+    debug2('add-dep: %r < %s %r\n' % (sn, mode, reldep))
+    
+    open(sn, 'a').write('%s %s\n' % (mode, reldep))
 
 
 def deps(t):