build/utils: Allow python functions to execute with real exception handling

With the code as it stands today it not possible to execute a python function
and get "normal" python exception handling behaviour. If a python function
raises an exception, it forces a traceback to be printed and the exception
becomes a FuncFailed exception.

This adds in a parameter 'pythonexception' which allows standard python
exceptions to be passed unchanged with no traceback. Ultimately we may want
to change to this convention in various places but at least it means we can
start to add sane functions now.

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

1 files changed, 11 insertions, 4 deletions

diff --git a/lib/bb/build.py b/lib/bb/build.py
index d20ee065b..db5072cb4 100644
--- a/lib/bb/build.py
+++ b/lib/bb/build.py
@@ -156,7 +156,12 @@ class LogTee(object):
     def flush(self):
         self.outfile.flush()
 
-def exec_func(func, d, dirs = None):
+#
+# pythonexception allows the python exceptions generated to be raised
+# as the real exceptions (not FuncFailed) and without a backtrace at the 
+# origin of the failure.
+#
+def exec_func(func, d, dirs = None, pythonexception=False):
     """Execute a BB 'function'"""
 
     body = d.getVar(func, False)
@@ -224,7 +229,7 @@ def exec_func(func, d, dirs = None):
 
     with bb.utils.fileslocked(lockfiles):
         if ispython:
-            exec_func_python(func, d, runfile, cwd=adir)
+            exec_func_python(func, d, runfile, cwd=adir, pythonexception=pythonexception)
         else:
             exec_func_shell(func, d, runfile, cwd=adir)
 
@@ -232,7 +237,7 @@ _functionfmt = """
 {function}(d)
 """
 logformatter = bb.msg.BBLogFormatter("%(levelname)s: %(message)s")
-def exec_func_python(func, d, runfile, cwd=None):
+def exec_func_python(func, d, runfile, cwd=None, pythonexception=False):
     """Execute a python BB 'function'"""
 
     code = _functionfmt.format(function=func)
@@ -256,10 +261,12 @@ def exec_func_python(func, d, runfile, cwd=None):
         bb.methodpool.insert_method(func, text, fn, lineno - 1)
 
         comp = utils.better_compile(code, func, "exec_python_func() autogenerated")
-        utils.better_exec(comp, {"d": d}, code, "exec_python_func() autogenerated")
+        utils.better_exec(comp, {"d": d}, code, "exec_python_func() autogenerated", pythonexception=pythonexception)
     except (bb.parse.SkipRecipe, bb.build.FuncFailed):
         raise
     except:
+        if pythonexception:
+            raise
         raise FuncFailed(func, None)
     finally:
         bb.debug(2, "Python function %s finished" % func)