Commit 7644d557df (Check*: Refactor variable handling, 2026-07-20,
v4.4.1~12^2~1) introduced a subtle regression in the handling of
`CMAKE_REQUIRED_LINK_OPTIONS` and `CMAKE_REQUIRED_LIBRARIES` which
resulted in an error if these were set to a 'false-like' value. This
could happen, for example, if the user passes `<name>_LIBS`, which
happens to have the value `<name>-NOTFOUND`. Previously, such values
would be ignored.
Fix it by separately checking for user- or module-provided link options
or link libraries. (We were already doing this for the other variables
used to propagate requirements into checks.)
Fixes: #28026
Commit a72e241200 (Check*: Restore more toleration of `;-W...` in
CMAKE_REQUIRED_FLAGS, 2026-07-21) updated the Check* modules to share
required-flag handling without adding coverage for those paths.
Exercise each probe with required definitions followed by a warning
option.
Without the compatibility handling, CMake rejects the warning option.
Without the required definitions, all seven checks fail to find their
header, functions, prototype, or type.
Issue: #28001
Introduce a mechanism (via the private and undocumented `ISSUE_WARNING`
option to the `cmake_policy` command) to allow built-in modules to issue
policy warnings. Update modules to use this.
This allows modules to issue policy warnings with the `CMD_POLICY`
diagnostic type, which is consistent with internally issued diagnostics.
This also tends to simplify the logic for issuing such warnings in much
the way the helpers introduced in the previous commit did for the C++
code.
Tweak `cmMessenger` to also show the "warning is for project developers"
notice for all diagnostics that are descendants of the `CMD_AUTHOR`
category. When doing so, also show both command-line options which can
suppress the message.
Update expected test output to account for the new format of diagnostic
messages. These changes were applied entirely by `sed` using the
following commands:
- `/Use -Wno-dev to suppress/s/-Wno-dev/-Wno-author/g`
- `s/Warning [\\][(]dev[\\][)]/Warning \\(author\\)/g`
- `s/CMake Deprecation Warning/CMake Warning \\(deprecated\\)/g`
This is not a complete fix, but covers a significant fraction of the
needed changes, and this commit is strictly automated changes.
Changes:
- Added new `RESULT_VARIABLE` keyword to enable customizing the name of
the internal cache variable, which contains the boolean result of the
check.
- The macro check_type_size() changed to function for easier arguments
handling.
- Documentation synced and extended to better understand the
check_type_size() command. Some typos fixed in the initial example.
- CheckTypeSize tests adjusted so also C++ is tested.
- Error messages slightly adjusted when checking the LANGUAGE argument.
Closes: #27202
For policy-specific tests, use the version before the policy was
introduced. Otherwise, use 3.5 where possible.
Also, remove `cmake_minimum_required()` and `project()` calls from
individual cases where they are handled by `CMakeLists.txt`.
The OLD behaviors of all policies are deprecated, but only by
documentation. Add an explicit deprecation diagnostic for policies
introduced in CMake 3.12 and below to encourage projects to port
away from setting policies to OLD.
Other check modules honor this variable, so include file checks should
too. Add policy `CMP0075` to enable the behavior in a compatible way.
This change was originally made by commit v3.11.0-rc1~108^2
(CheckIncludeFiles: Honor CMAKE_REQUIRED_LIBRARIES, 2017-12-24) but it
was reverted by commit v3.11.1~9^2 (Revert "CheckIncludeFiles: Honor
CMAKE_REQUIRED_LIBRARIES", 2018-04-04) because the behavior change could
affect checks in existing projects in an incompatible way.
Fixes: #9514
Expect tests to specify stderr content if it is present.
Fix the CMP0019 test, which has only been testing the WARN status
until now. Specify in the CommandLine and FPHSA tests that content
is at least one character.
Set policies in the Language and CheckModules tests, which have empty
test output, modulo unrelated policies on some platforms.
Enable the C and CXX languages only in the test cases that really need
them. In the failure cases we do not get far enough to really use the
languages, so skip enabling them.
Previously if headers required to check if a struct has a member can be
compiled with C++ compiler only, the check would fail because the C
compiler fails. As a consequence, the result variable would be set to
false, even if the struct has that particular member.
Teach CHECK_STRUCT_HAS_MEMBER to accept a new optional argument LANGUAGE
that allows one to explicitly set the compiler to use. The new
signature is therefore:
CHECK_STRUCT_HAS_MEMBER (<struct> <member> <header> <variable>
[LANGUAGE <language>])
Matthew Woehlke
Josef Šimánek
AJIOB
Hanna Rusakovich
Peter Kokot
Brad King
Aliaksandr Averchanka
David Adam
Stephen Kelly
Daniele E. Domenichelli