Make exception handling thread-safe by using sys.exc_info() instead of sys.exc_{type,value}.

2 files changed, 11 insertions, 14 deletions

diff --git a/src/engine/SCons/Script/SConscript.py b/src/engine/SCons/Script/SConscript.py
index 81450e9..074477f 100644
--- a/src/engine/SCons/Script/SConscript.py
+++ b/src/engine/SCons/Script/SConscript.py
@@ -270,7 +270,8 @@ def SConscript_exception(file=sys.stderr):
     This will show users who have Python errors where the problem is,
     without cluttering the output with all of the internal calls leading
     up to where we exec the SConscript."""
-    stack = traceback.extract_tb(sys.exc_traceback)
+    exc_type, exc_value, exc_tb = sys.exc_info()
+    stack = traceback.extract_tb(exc_tb)
     last_text = ""
     found = 0
     i = 0
@@ -284,10 +285,10 @@ def SConscript_exception(file=sys.stderr):
         # We did not find our exec statement, so this was actually a bug
         # in SCons itself.  Show the whole stack.
         i = 0
-    type = str(sys.exc_type)
+    type = str(exc_type)
     if type[:11] == "exceptions.":
         type = type[11:]
-    file.write('%s: %s:\n' % (type, sys.exc_value))
+    file.write('%s: %s:\n' % (type, exc_value))
     for fname, line, func, text in stack[i:]:
         file.write('  File "%s", line %d:\n' % (fname, line))
         file.write('    %s\n' % text)
diff --git a/src/engine/SCons/Script/__init__.py b/src/engine/SCons/Script/__init__.py
index 2dbb961..87e9602 100644
--- a/src/engine/SCons/Script/__init__.py
+++ b/src/engine/SCons/Script/__init__.py
@@ -153,18 +153,12 @@ class BuildTask(SCons.Taskmaster.Task):
         # is to display the various types of Errors and Exceptions
         # appropriately.
         status = 2
-        e = sys.exc_value
-        t = sys.exc_type
+        t, e = self.exc_info()[:2]
         tb = None
-        if t is SCons.Errors.TaskmasterException:
-            # The Taskmaster received an Error or Exception while trying
-            # to process or build the Nodes and dependencies, which it
-            # wrapped up for us in the object recorded as the value of
-            # the Exception, so process the wrapped info instead of the
-            # TaskmasterException itself.
-            t = e.type
-            tb = e.traceback
-            e = e.value
+        if t is None:
+            # The Taskmaster didn't record an exception for this Task;
+            # see if the sys module has one.
+            t, e = sys.exc_info()[:2]
 
         if t == SCons.Errors.BuildError:
             sys.stderr.write("scons: *** [%s] %s\n" % (e.node, e.errstr))
@@ -187,6 +181,8 @@ class BuildTask(SCons.Taskmaster.Task):
 
         self.do_failed(status)
 
+        self.exc_clear()
+
     def make_ready(self):
         """Make a task ready for execution"""
         SCons.Taskmaster.Task.make_ready(self)