The TRANSFORM action registry held one live action instance per action for
the whole process, and each instance carried per-call state: a raw Selector
pointer, REPLACE's helper, APPEND/PREPEND's operands. That was harmless
while every action ran to completion uninterrupted, but commit c7af6e94d8
(list(TRANSFORM): Add PREDICATE selector, 2026-04-08, v4.4.0-rc1) added a
selector that runs a user function once per element, interleaved with the
transform. User code reentering list(TRANSFORM) with the same action now
rebinds the shared instance mid-flight. That produces silently wrong
results, and a use-after-free once any element is transformed after the
reentering one. It needs no unusual code to hit: a predicate calling
find_package(Python) reaches list(TRANSFORM ... REPLACE) inside FindPython's
own module.
Make action objects immutable and per-call. Operands and the selector become
constructor arguments, Initialize is deleted, and the registry becomes a
constexpr table of metadata with a MakeTransformAction factory. The
InSelection guard, duplicated in all eight actions, moves into the base class.
This also closes a second hole in the same machinery. TransformActionApply
overrode only the vector form of Initialize, so transform(APPLY, "f",
selector) dispatched to the empty two-argument virtual in the base, left
Selector null, and dereferenced it. With no virtual Initialize left to
inherit, an APPLY action without a cmMakefile is no longer constructible, so
the throwing stub that guarded the vector form is no longer needed.
Close a third, from commit 651f82642c (Add APPLY action for list(TRANSFORM),
2026-04-08, v4.4.0-rc1): the cmMakefile overload performs APPLY
unconditionally but validated only the arity of the action passed to it.
APPEND, PREPEND and APPLY all take one argument, so transform(APPEND, "x",
makefile) passed validation and then silently ran APPLY, calling "x" as a
function instead of appending it. Reject any action but APPLY up front.
That path is unreachable from CMake code, since HandleTransformCommand only
selects the overload for APPLY, and Tests/CMakeLib has no cmMakefile to drive
it with, so it carries no test.
Document the predicate's evaluation order while here. It runs once per
element, immediately before that element would be transformed. The manual
did not state the timing, which matters precisely because a predicate that
reenters list(TRANSFORM) observes the outer call mid-flight.
Fixes: #28031
Allow users to provide a custom comparison function for `list(SORT)`.
The comparator is validated for strict weak ordering at runtime to
produce a clear CMake error rather than a platform-dependent abort.
Closes: #27761
Add a new `PREDICATE` selector to `list(TRANSFORM)` that uses a
user-defined function or macro to decide which elements to transform.
The predicate callable receives each element value and an output
variable name. It must set the output variable to a truthy or falsy
value in PARENT_SCOPE; only elements for which the predicate returns
true are passed to the transform action.
Adds a shared PredicateEvaluator helper class used by both TRANSFORM
PREDICATE and (in a subsequent commit) FILTER PREDICATE.
Includes parser wiring, error and success tests covering all existing
actions (TOUPPER, TOLOWER, REPLACE, STRIP, GENEX_STRIP, APPEND,
PREPEND, APPLY) combined with the PREDICATE selector.
Issue: #27761
Add a new APPLY action to list(TRANSFORM) that invokes a user-defined
function or macro for each element of the list, enabling arbitrary
per-element transformations.
The callable receives the current element value and an output variable
name, and must set the output variable in PARENT_SCOPE to the
transformed value.
Includes documentation, release notes, and tests for both function
and macro callables, OUTPUT_VARIABLE, error cases, and selector
combinations (AT, FOR, REGEX).
Refs: #27761
When doing successive matches, track the input start and current search
start positions separately to prevent the `^` anchor from matching in
the middle of the string. Add policy CMP0186 to provide compatibility.
Issue: #26629Fixes: #16899
Since commit 84db8506ff (Deprecate compatibility with CMake versions older
than 3.10, 2024-10-03, v3.31.0-rc1~23^2) the `cmake_minimum_required` and
`cmake_policy` commands warn if the project does not enable policies as
of 3.10 or higher. Clarify the advice given in the warning message about
how to update the version specification, particularly without actually
requiring a newer minimum version of CMake.
Issue a deprecation warning on calls to `cmake_minimum_required` or
`cmake_policy` that set policies based on versions older than 3.10.
Note that the effective policy version includes `...<max>` treatment.
Update the check from commit 3a4791548d (Deprecate compatibility with
CMake versions older than 3.5, 2023-02-09, v3.27.0-rc1~508^2).
Issue a deprecation warning on calls to `cmake_minimum_required` or
`cmake_policy` that set policies based on versions older than 3.5.
Note that the effective policy version includes `...<max>` treatment.
Update the check from commit 5845c218d7 (Deprecate compatibility with
CMake versions older than 2.8.12, 2020-06-12, v3.19.0-rc1~629^2).
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`.
Fixes crashes involving invalid ranges specified in list(TRANSFORM ...
FOR ...) calls.
* Report error when step is not positive
* Report error when start is after stop
Fixes: #22985
Issue a deprecation warning on calls to `cmake_minimum_required` or
`cmake_policy` that set policies based on versions older than 2.8.12.
Note that the effective policy version includes `...<max>` treatment.
This is important in combination with commit ca24b70d31 (Export: Specify
a policy range in exported files, 2020-05-16, v3.18.0-rc1~133^2).
The operations changed here all are no-ops on empty lists anyways, so
just have them succeed when given non-extant lists.
- `list(REMOVE_ITEM)`
- `list(REMOVE_DUPLICATES)`
- `list(SORT)`
- `list(FILTER)`
- `list(REVERSE)`
Move failure cases from the CMake.{If,List,While,GetProperty} tests over
to the RunCMake.{if,list,while,get_property} tests to use the more
modern infrastructure. This also avoids using REGEX_ESCAPE_STRING to
try to regex-match full paths.
Set the minimum required version of CMake high enough to avoid the
warning for CMAKE_LEGACY_CYGWIN_WIN32. The warning appears on stderr
and breaks the expected output matching.
Since commit ed1ea24c (Fix INSERT to allow inserting to empty list,
2006-05-15) the list command allows insertion into an empty list at
index 0. Fix rejection of insertion at non-zero (negative) indices to
present an error message instead of crashing.
While at it, fix the error message of the GET and REMOVE_AT operations
when the list is empty to not present a bogus allowed range.
Add a "RunCMake.list" test to cover failure cases on empty lists.
Mickaël Germain
AJIOB
Nikita Nemkin
Brad King
Marc Chevrier
Adriaan de Groot
Nick Muggio
Asit Dhal
Alex Turbov
Kyle Edwards
Ben Boeckel
Daniel Chabrowski
Daniel Franke
Marc Chevrier
Ashley Whetter