From 69255b51d43a8d12096f3e2bf711045567952caa Mon Sep 17 00:00:00 2001
From: stevenknight <stevenknight@fdb21ef1-2011-0410-befe-b5e4ea1792b1>
Date: Sat, 5 Mar 2005 04:22:52 +0000
Subject: [PATCH] Fix stack trace when there's no scanner in an Environment.

git-svn-id: http://scons.tigris.org/svn/scons/trunk@1243 fdb21ef1-2011-0410-befe-b5e4ea1792b1
---
 src/engine/SCons/Environment.py      | 6 ++----
 src/engine/SCons/EnvironmentTests.py | 6 ++++++
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/engine/SCons/Environment.py b/src/engine/SCons/Environment.py
index 10787a7a..2f11f061 100644
--- a/src/engine/SCons/Environment.py
+++ b/src/engine/SCons/Environment.py
@@ -569,12 +569,10 @@ class Base(SubstitutionEnvironment):
         
     def get_scanner(self, skey):
         """Find the appropriate scanner given a key (usually a file suffix).
-        __cacheable__
         """
         sm = self._gsm()
-        if sm.has_key(skey):
-            return sm[skey]
-        return None
+        try: return sm[skey]
+        except (KeyError, TypeError): return None
 
     def _smd(self):
         "__reset_cache__"
diff --git a/src/engine/SCons/EnvironmentTests.py b/src/engine/SCons/EnvironmentTests.py
index bfd12620..1772407a 100644
--- a/src/engine/SCons/EnvironmentTests.py
+++ b/src/engine/SCons/EnvironmentTests.py
@@ -708,6 +708,12 @@ class BaseTestCase(unittest.TestCase):
 
         suffixes = [".c", ".cc", ".cxx", ".m4", ".m5"]
 
+        env = Environment()
+        try: del env['SCANNERS']
+        except KeyError: pass
+        s = map(env.get_scanner, suffixes)
+        assert s == [None, None, None, None, None], s
+
         env = Environment(SCANNERS = [])
         s = map(env.get_scanner, suffixes)
         assert s == [None, None, None, None, None], s
-- 
2.26.2