bitbake: cache/ConfHandler: Drop TOPDIR/chdir manipulations

This code has been unchanged since 2006 apart from attempts to optimise
performance by minimising chdir() calls.

There is no reason the modern bitbake parser should be changing directory
all the time. We did have some path assumptions in the mists of time but
those were resovled and the code is deterministic and doesn't depend on
cwd now for parsing. We can therefore drop the changes in directory.

Also, TOPDIR is now being set by cookerdata in all cases so we don't
need the fallbacks in this code (which was used to effectively initialise
a value). We don't need to change TOPDIR when parsing a recipe, that makes
no sense. If we stop all the other messing around, we don't need to expand
TMPDIR either.

These changes have the potential to break some obscure use cases such
as an anonymous function assuming the current working directory, or some
case which depends on TOPDIR changing but I believe any such uses should
be fixed at this point.

(Bitbake rev: add5d488e1d6607a98441836075d01cb1dc9c0fa)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/cache.py

@@ -284,36 +284,15 @@ def parse_recipe(bb_data, bbfile, appends, mc=''):
     Parse a recipe
     """
 
-    chdir_back = False
-
     bb_data.setVar("__BBMULTICONFIG", mc)
 
-    # expand tmpdir to include this topdir
-    bb_data.setVar('TMPDIR', bb_data.getVar('TMPDIR') or "")
     bbfile_loc = os.path.abspath(os.path.dirname(bbfile))
-    oldpath = os.path.abspath(os.getcwd())
     bb.parse.cached_mtime_noerror(bbfile_loc)
 
-    # The ConfHandler first looks if there is a TOPDIR and if not
-    # then it would call getcwd().
-    # Previously, we chdir()ed to bbfile_loc, called the handler
-    # and finally chdir()ed back, a couple of thousand times. We now
-    # just fill in TOPDIR to point to bbfile_loc if there is no TOPDIR yet.
-    if not bb_data.getVar('TOPDIR', False):
-        chdir_back = True
-        bb_data.setVar('TOPDIR', bbfile_loc)
-    try:
-        if appends:
-            bb_data.setVar('__BBAPPEND', " ".join(appends))
-        bb_data = bb.parse.handle(bbfile, bb_data)
-        if chdir_back:
-            os.chdir(oldpath)
-        return bb_data
-    except:
-        if chdir_back:
-            os.chdir(oldpath)
-        raise
-
+    if appends:
+        bb_data.setVar('__BBAPPEND', " ".join(appends))
+    bb_data = bb.parse.handle(bbfile, bb_data)
+    return bb_data
 
 
 class NoCache(object):

bitbake/lib/bb/parse/parse_py/ConfHandler.py

@@ -48,10 +48,7 @@ __unset_regexp__ = re.compile( r"unset\s+([a-zA-Z0-9\-_+.${}/~]+)$" )
 __unset_flag_regexp__ = re.compile( r"unset\s+([a-zA-Z0-9\-_+.${}/~]+)\[([a-zA-Z0-9\-_+.]+)\]$" )
 
 def init(data):
-    topdir = data.getVar('TOPDIR', False)
-    if not topdir:
-        data.setVar('TOPDIR', os.getcwd())
-
+    return
 
 def supports(fn, d):
     return fn[-5:] == ".conf"