mojo/public/tools/mojom/version_compatibility_unittest.py
def testInterfaceMethodReplyParamsChanged(self):
    """Similar to request parameters, a change to reply parameters is considered
    backward-compatible if it meets the same backward-compatibility
    requirements imposed on equivalent struct changes."""
    self.assertNotBackwardCompatible('interface F { A() => (); };',
                                     'interface F { A() => (int32 x); };')
    self.assertNotBackwardCompatible('interface F { A() => (int32 x); };',
                                     'interface F { A() => (); };')
    self.assertNotBackwardCompatible('interface F { A() => (bool x); };',
                                     'interface F { A() => (int32 x); };')

    self.assertBackwardCompatible('interface F { A() => (int32 a); };',
                                  'interface F { A() => (int32 x); };')
    self.assertBackwardCompatible(
        'interface F { A() => (int32 x); };',
        'interface F { A() => (int32 x, [MinVersion] string? s); };')
Similar to request parameters, a change to reply parameters is considered
    backward-compatible if it meets the same backward-compatibility
    requirements imposed on equivalent struct changes.
Similar to request parameters, a change to reply parameters is considered
backward-compatible if it meets the same backward-compatibility
requirements imposed on equivalent struct changes.
Similar to request parameters a change to reply parameters is considered backward - compatible if it meets the same backward - compatibility requirements imposed on equivalent struct changes .
def testInterfaceMethodReplyParamsChanged(self):
    self.assertNotBackwardCompatible('interface F { A() => (); };',
                                     'interface F { A() => (int32 x); };')
    self.assertNotBackwardCompatible('interface F { A() => (int32 x); };',
                                     'interface F { A() => (); };')
    self.assertNotBackwardCompatible('interface F { A() => (bool x); };',
                                     'interface F { A() => (int32 x); };')
    self.assertBackwardCompatible('interface F { A() => (int32 a); };',
                                  'interface F { A() => (int32 x); };')
    self.assertBackwardCompatible(
        'interface F { A() => (int32 x); };',
        'interface F { A() => (int32 x, [MinVersion] string? s); };')
def testInterfaceMethodReplyParamsChanged ( self ) : self . assertNotBackwardCompatible ( 'interface F { A() => (); };' , 'interface F { A() => (int32 x); };' ) self . assertNotBackwardCompatible ( 'interface F { A() => (int32 x); };' , 'interface F { A() => (); };' ) self . assertNotBackwardCompatible ( 'interface F { A() => (bool x); };' , 'interface F { A() => (int32 x); };' ) self . assertBackwardCompatible ( 'interface F { A() => (int32 a); };' , 'interface F { A() => (int32 x); };' ) self . assertBackwardCompatible ( 'interface F { A() => (int32 x); };' , 'interface F { A() => (int32 x, [MinVersion] string? s); };' )
Similar to request parameters, a change to reply parameters is considered
backward-compatible if it meets the same backward-compatibility
requirements imposed on equivalent struct changes.
Similar to request parameters a change to reply parameters is considered backward - compatible if it meets the same backward - compatibility requirements imposed on equivalent struct changes .
"""Similar to request parameters, a change to reply parameters is considered
    backward-compatible if it meets the same backward-compatibility
    requirements imposed on equivalent struct changes."""
self