Allow mismatches of broader exception declarations in .pxd signatures as long...

Allow mismatches of broader exception declarations in .pxd signatures as long the implemented signature is covered.

Cython/Compiler/PyrexTypes.py

@@ -2712,11 +2712,17 @@ class CFuncType(CType):
             return 0
         if self.nogil != other_type.nogil:
             return 0
-        if not self.exception_check and other_type.exception_check:
-            # a redundant exception check doesn't make functions incompatible, but a missing one does
-            return 0
-        if not self._same_exception_value(other_type.exception_value):
+        # narrower exception checks are ok, but prevent mismatches
+        if self.exception_check == '+' and other_type.exception_check != '+':
+            # must catch C++ exceptions if we raise them
             return 0
+        if not other_type.exception_check or other_type.exception_value is not None:
+            # if other does not *always* check exceptions, self must comply
+            if not self._same_exception_value(other_type.exception_value):
+                return 0
+            if self.exception_check and self.exception_check != other_type.exception_check:
+                # a redundant exception check doesn't make functions incompatible, but a missing one does
+                return 0
         self.original_sig = other_type.original_sig or other_type
         return 1
 

Cython/Compiler/Symtab.py

@@ -771,6 +771,10 @@ class Scope(object):
                     else:
                         warning(pos, "Function signature does not match previous declaration", 1)
                         entry.type = type
+                elif not in_pxd and entry.defined_in_pxd and type.compatible_signature_with(entry.type):
+                    # TODO: check that this was done by a signature optimisation and not a user error.
+                    #warning(pos, "Function signature does not match previous declaration", 1)
+                    entry.type = type
                 else:
                     error(pos, "Function signature does not match previous declaration")
         else:

tests/errors/pxd_signature_mismatch.pxd

+# OK
+
+cdef int wider_exception_check(int x, int y) except? 0
+
+cdef int no_exception_raised(int x, int y) except *
+
+cdef int any_exception_value1(int x, int y) except *
+
+cdef int any_exception_value2(int x, int y) except *
+
+cdef int any_exception_value3(int x, int y) except *
+
+cdef int any_exception_value4(int x, int y) except *
+
+cdef int optimised_exception_value(int x, int y) except? -1
+
+# NOK
 
 cdef int wrong_args(int x, long y)
 
 cdef long wrong_return_type(int x, int y)
 
-cdef int wrong_exception_check(int x, int y) except 0
+cdef int foreign_exception_value(int x, int y) except 0
+
+cdef int narrower_exception_check(int x, int y) except 0
 
 cdef int wrong_exception_value(int x, int y) except 0
 
 cdef int wrong_exception_value_check(int x, int y) except 0
 
-cdef int inherit_exception_value(int x, int y) except 0
+cdef int wrong_exception_value_optimised_check(int x, int y) except? -2
+
+cdef int wrong_exception_value_optimised(int x, int y) except -2
 
-cdef int inherit_exception_check(int x, int y) except *
+cdef int narrower_exception_check_optimised(int x, int y) except -1

tests/errors/pxd_signature_mismatch.pyx

 # mode: error
 # tag: pxd
 
+# OK
+
+cdef int wider_exception_check(int x, int y) except 0:
+    return 2
+
+cdef int no_exception_raised(int x, int y):
+    return 2
+
+cdef int any_exception_value1(int x, int y) except *:
+    return 2
+
+cdef int any_exception_value2(int x, int y) except -1:
+    return 2
+
+cdef int any_exception_value3(int x, int y) except -2:
+    return 2
+
+cdef int any_exception_value4(int x, int y) except? -2:
+    return 2
+
+cdef int optimised_exception_value(int x, int y) except *:  # => except? -1
+    return 2
+
+
+# NOK
+
 cdef int wrong_args(int x, int y):
     return 2
 
 cdef int wrong_return_type(int x, int y):
     return 2
 
-cdef int wrong_exception_check(int x, int y) except? 0:
+cdef int foreign_exception_value(int x, int y):
+    return 2
+
+cdef int narrower_exception_check(int x, int y) except? 0:
     return 2
 
 cdef int wrong_exception_value(int x, int y) except 1:
@@ -16,19 +45,24 @@ cdef int wrong_exception_value(int x, int y) except 1:
 cdef int wrong_exception_value_check(int x, int y) except? 1:
     return 2
 
-cdef int inherit_exception_value(int x, int y):
+cdef int wrong_exception_value_optimised_check(int x, int y) except *:
+    return 2
+
+cdef int wrong_exception_value_optimised(int x, int y) except *:
     return 2
 
-cdef int inherit_exception_check(int x, int y):
+cdef int narrower_exception_check_optimised(int x, int y) except *:
     return 2
 
 
 _ERRORS = """
-4:5: Function signature does not match previous declaration
-7:5: Function signature does not match previous declaration
-10:5: Function signature does not match previous declaration
-13:5: Function signature does not match previous declaration
-16:5: Function signature does not match previous declaration
-19:5: Function signature does not match previous declaration
-22:5: Function signature does not match previous declaration
+30:5: Function signature does not match previous declaration
+33:5: Function signature does not match previous declaration
+36:5: Function signature does not match previous declaration
+39:5: Function signature does not match previous declaration
+42:5: Function signature does not match previous declaration
+45:5: Function signature does not match previous declaration
+48:5: Function signature does not match previous declaration
+51:5: Function signature does not match previous declaration
+54:5: Function signature does not match previous declaration
 """

tests/run/excvalue_pxd.srctree

+PYTHON setup.py build_ext --inplace
+PYTHON -c "import foo"
+PYTHON -c "import a"
+
+######## setup.py ########
+
+from Cython.Build import cythonize
+from distutils.core import setup
+
+setup(
+  ext_modules = cythonize("*.pyx"),
+)
+
+######## foo.pxd ########
+
+cdef int bar(int i) except *
+
+######## foo.pyx ########
+
+cdef int bar(int i) except *:
+    if i == 10:
+        raise ValueError()
+    return i + 1
+
+######## a.pyx ########
+
+cimport cython
+from foo cimport bar
+
+def test():
+    assert bar(-2) == -1
+    try:
+        bar(10)
+    except ValueError:
+        pass
+    else:
+        assert False, "exception not raised"