Internal CL 156157936, which was published in commit
fe402c2779, introduced undefined behavior
by casting a base class (internal::{Naggy,Nice,Strict}Base<MockClass>,
using the curiously recurring template pattern) pointer to a derived
class ({Naggy,Nice,Strict}Mock<MockClass>), in the base class'
constructor. At that point, the object isn't guaranteed to have taken on
the shape of the derived class, and casting is undefined behavior.
The undefined behavior was caught by Chrome's CFI build bot [1], and
prevents rolling googletest past that commit / CL.
This commit simplifies the {Naggy,Nice,Strict}Mock class hierarchy in
a way that removes the undefined behavior.
[1] https://www.chromium.org/developers/testing/control-flow-integrity
Commit fe402c2779 published the changes in
internal CL 156157936, but missed the diff in
gmock-generated-nice-strict.h.pump. This makes it difficult to reason
about the change, because the .pump file is more concise than the
generated file.
This PR was tested by re-generating the .h file using the command below
and checking the git diff.
./googletest/scripts/pump.py \
googlemock/include/gmock/gmock-generated-nice-strict.h.pump
As of recently, Google Test fails to compile with the warning below when
used in projects with strict warning settings.
googletest/src/gtest-death-test.cc:1004:13: error: unused function 'StackGrowsDown' [-Werror,-Wunused-function]
ContainsUnprintableControlCodes() in gtest-printers.cc passes a char
argument to std::iscntrl. Although its argument is an int, std::iscntrl
produces undefined behavior if its argument is not representable as an
unsigned char. The standard library on Windows asserts that the argument
is an unsigned char, resulting in an assertion crash on debug builds.
Victor Costan