Make 'import portage' statements more tolerant to broken source statements

in make.conf since exceptions thrown during 'import portage' statements
can practically render the api unusable for api consumers. Thanks to lxnay
for the suggestion. (trunk r9400)

svn path=/main/branches/2.1.2/; revision=9401

2 files changed, 28 insertions, 3 deletions

diff --git a/pym/portage.py b/pym/portage.py
index 97e3bbf12..b8da8d9b6 100644
--- a/pym/portage.py
+++ b/pym/portage.py
@@ -1104,7 +1104,11 @@ class config:
 		@type local_config: Boolean
 		"""
 
-		debug = os.environ.get("PORTAGE_DEBUG") == "1"
+		# When initializing the global portage.settings instance, avoid
+		# raising exceptions whenever possible since exceptions thrown
+		# from 'import portage' or 'import portage.exceptions' statements
+		# can practically render the api unusable for api consumers.
+		tolerant = "_initializing_globals" in globals()
 
 		self.already_in_regenerate = 0
 
@@ -1377,7 +1381,7 @@ class config:
 
 			self.mygcfg = getconfig(
 				os.path.join(config_root, MAKE_CONF_FILE.lstrip(os.path.sep)),
-				allow_sourcing=True)
+				tolerant=tolerant, allow_sourcing=True)
 			if self.mygcfg is None:
 				self.mygcfg = {}
 
@@ -9997,7 +10001,10 @@ def init_legacy_globals():
 	for k, envvar in (("config_root", "PORTAGE_CONFIGROOT"), ("target_root", "ROOT")):
 		kwargs[k] = os.environ.get(envvar, "/")
 
+	global _initializing_globals
+	_initializing_globals = True
 	db = create_trees(**kwargs)
+	del _initializing_globals
 
 	settings = db["/"]["vartree"].settings
 	portdb = db["/"]["porttree"].dbapi
diff --git a/pym/portage_util.py b/pym/portage_util.py
index 486376bfc..902ed091f 100644
--- a/pym/portage_util.py
+++ b/pym/portage_util.py
@@ -16,6 +16,11 @@ except ImportError:
 if not hasattr(__builtins__, "set"):
 	from sets import Set as set
 
+try:
+	import cStringIO as StringIO
+except ImportError:
+	import StringIO
+
 noiselimit = 0
 
 def writemsg(mystr,noiselevel=0,fd=None):
@@ -291,6 +296,15 @@ def writedict(mydict,myfilename,writekey=True):
 		return 0
 	return 1
 
+class _tolerant_shlex(shlex.shlex):
+	def sourcehook(self, newfile):
+		try:
+			return shlex.shlex.sourcehook(self, newfile)
+		except EnvironmentError, e:
+			writemsg("!!! Parse error in '%s': source command failed: %s\n" % \
+				(self.infile, str(e)), noiselevel=-1)
+			return (newfile, StringIO.StringIO())
+
 def getconfig(mycfg, tolerant=0, allow_sourcing=False, expand=True):
 	mykeys={}
 	try:
@@ -302,10 +316,14 @@ def getconfig(mycfg, tolerant=0, allow_sourcing=False, expand=True):
 			raise
 		return None
 	try:
+		if tolerant:
+			shlex_class = _tolerant_shlex
+		else:
+			shlex_class = shlex.shlex
 		# The default shlex.sourcehook() implementation
 		# only joins relative paths when the infile
 		# attribute is properly set.
-		lex = shlex.shlex(f, infile=mycfg, posix=True)
+		lex = shlex_class(f, infile=mycfg, posix=True)
 		lex.wordchars=string.digits+string.letters+"~!@#$%*_\:;?,./-+{}"     
 		lex.quotes="\"'"
 		if allow_sourcing: