Add a function to compute a class's method resolution order. This is
easy for 2.2 new-style classes, but trickier for classic classes, and
different approaches are needed "depending". The function will allow
later code to treat all flavors of classes uniformly.
diff --git a/Lib/inspect.py b/Lib/inspect.py
index 1102c3b..3febf18 100644
--- a/Lib/inspect.py
+++ b/Lib/inspect.py
@@ -163,6 +163,24 @@
results.sort()
return results
+# ----------------------------------------------------------- class helpers
+def _searchbases(cls, accum):
+ # Simulate the "classic class" search order.
+ if cls in accum:
+ return
+ accum.append(cls)
+ for base in cls.__bases__:
+ _searchbases(base, accum)
+
+def getmro(cls):
+ "Return tuple of base classes (including cls) in method resolution order."
+ if hasattr(cls, "__mro__"):
+ return cls.__mro__
+ else:
+ result = []
+ _searchbases(cls, result)
+ return tuple(result)
+
# -------------------------------------------------- source code extraction
def indentsize(line):
"""Return the indent size, in spaces, at the start of a line of text."""
diff --git a/Lib/test/test_inspect.py b/Lib/test/test_inspect.py
index 130fa8e..dbb6609 100644
--- a/Lib/test/test_inspect.py
+++ b/Lib/test/test_inspect.py
@@ -213,3 +213,23 @@
os.unlink(fname)
except:
pass
+
+# Test classic-class method resolution order.
+class A: pass
+class B(A): pass
+class C(A): pass
+class D(B, C): pass
+
+expected = (D, B, A, C)
+got = inspect.getmro(D)
+test(expected == got, "expected %r mro, got %r", expected, got)
+
+# The same w/ new-class MRO.
+class A(object): pass
+class B(A): pass
+class C(A): pass
+class D(B, C): pass
+
+expected = (D, B, C, A, object)
+got = inspect.getmro(D)
+test(expected == got, "expected %r mro, got %r", expected, got)