CMP0215ΒΆ
Added in version 4.4.
Ninja Generators emit Swift modules separately from compilation.
In CMake 4.3 and below, Swift targets built by Ninja Generators
emit .swiftmodule from the Swift compile edge together with object files.
Because Ninja treats a build edge as atomic, downstream Swift targets
must wait for compilation outputs to finish before they can use the module
interface.
CMake 4.4 and above prefer to emit .swiftmodule from a dedicated
-emit-module build edge so that downstream Swift targets can begin
compiling as soon as the module interface is available. This policy
provides compatibility with projects that have not been updated.
The OLD behavior for this policy is to not emit modules separately.
The NEW behavior for this policy is to emit .swiftmodule from a
dedicated build edge for importable Swift targets by default.
The Swift_SEPARATE_MODULE_EMISSION target property and
corresponding CMAKE_Swift_SEPARATE_MODULE_EMISSION variable
may be set to enable or disable the behavior on a per-target basis.
Note
Separate module emission takes effect only when policy CMP0157
is set to NEW prior to the first project() or
enable_language() command that enables the Swift language.
The dedicated .swiftmodule edge is available only in the split
Swift build model.
This policy was introduced in CMake version 4.4.
It may be set by cmake_policy() or cmake_minimum_required().
If it is not set, CMake does not warn, and uses OLD behavior.
Note
The OLD behavior of a policy is
deprecated by definition
and may be removed in a future version of CMake.