When `$<LINK_ONLY:...>` is used outside of linking we may evaluate it
without a `dagChecker`. Do not dereference the NULL pointer and issue a
diagnostic instead.
Closes: #16287
Policy CMP0026 deprecated the LOCATION property, and we have long
provided a $<TARGET_FILE:...> generator expression. However, if
a project tries to use $<TARGET_PROPERTY:...,LOCATION> we should
at least not crash.
The compatibility implementation of the LOCATION property uses
cmGlobalGenerator::CreateGenerationObjects to create the structures
needed to evaluate the property before generation starts. The
implementation assumed that accessing the property could only be done
during configuration (via the typical get_property command use case).
The $<TARGET_PROPERTY:...,LOCATION> genex causes the LOCATION property
to be accessed during generation. Calling CreateGenerationObjects
during generation blows away all the objects currently being used for
generation and is not safe. Add a condition to call it only when
configuration is not finished.
Some commands on Windows do not understand forward slash paths and
require backslashes. In order to help projects generate shell
invocations of such commands, provide a generator expression to convert
paths to the shell-preferred path format for the current generator.
This will allow custom commands to generate paths the same way CMake
does for compiler command invocations.
Since support for generator expressions was added to OUTPUT_NAME it is
possible for project code to cause recursion in this method by using a
$<TARGET_FILE> genex. Detect and reject such cases.
If {ARCHIVE,LIBRARY,RUNTIME}_OUTPUT_DIRECTORY is set with a genex then
do not add the per-config subdirectory on multi-config generators.
This will allow projects to use $<CONFIG> to place the per-config
part of the directory path somewhere other than the end.
Teach the cmGeneratorExpressionEvaluator filesystem artifact logic
to reject OBJECT_LIBRARY targets since they have no main artifact.
Without the explicit rejection evaluation falls through to an
internal CMake error message in cmTarget::GetOutputInfo.
Extend the RunCMake.GeneratorExpression test to cover these cases.
Otherwise the comma is treated as plain text by ParseContent.
$<STREQUAL:,> should be valid and true.
$<STREQUAL:,something> should be valid and false.
$<STREQUAL:,,> should be non-valid as it is 3 parameters.
$<STREQUAL:something,,> should be non-valid as it is 3 parameters.
Additionally, this allows reporting the correct error for other
expressions. For example $<TARGET_PROPERTY:,> should be invalid
because it has an empty target and empty property. It shouldn't
attempt to read the property ',' on the 'implicit this' target.
This expression evaluates to '1' or '0' to indicate whether the build
configuration for which the expression is evaluated matches tha named
configuration. In combination with the "$<0:...>" and "$<1:...>"
expressions this allows per-configuration content to be generated.
Add generator expressions that combine and use boolean test results:
$<0:...> = empty string (ignores "...")
$<1:...> = content of "..."
$<AND:?[,?]...> = '1' if all '?' are '1', else '0'
$<OR:?[,?]...> = '0' if all '?' are '0', else '1'
$<NOT:?> = '0' if '?' is '1', else '1'
These will be useful to evaluate (future) boolean query expressions and
condition content on the results. Include tests and documentation.