qtp0008.qdoc

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// Copyright (C) 2026 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only
 
/*!
\page qt-cmake-policy-qtp0008.html
\ingroup qt-cmake-policies
\since 6.12
\title QTP0008
\keyword qt_cmake_policy_qtp0008
 
\summary {Forwards deploy script arguments without re-evaluating them.}
 
This policy was introduced in Qt 6.12. The policy affects how the version-less
\l{qt_generate_deploy_script()} and \l{qt_generate_deploy_app_script()} commands pass
their arguments to the implementation code.
 
Both commands used to be macros. A macro substitutes its arguments textually and
the result is parsed again, so escape sequences and \c{${}} references in the
argument values were evaluated a second time. Projects had to escape such values
twice to compensate.
 
If the policy is set to \c OLD, the values are forwarded through a macro, so they
are re-evaluated the way they used to be.
 
If the policy is set to \c NEW, the values are forwarded through a function, so
they remain unchanged.
 
When the policy is not set, the values are re-evaluated as with \c OLD, and an
\c{AUTHOR_WARNING} is emitted, but only if the re-evaluation actually changes one
of the values. The warning shows the values before and after, so that it is clear
what has to be adapted.
 
Consider the code snippet below:
\badcode
qt_generate_deploy_script(
    OUTPUT_SCRIPT deploy_script
    CONTENT "
qt_deploy_qt_conf(\"\${QT_DEPLOY_PREFIX}/qt.conf\")
"
)
\endcode
 
With the policy unset or \c OLD, the reference is expanded while the arguments are
forwarded, and the generated script ends up with \c{qt_deploy_qt_conf("/qt.conf")}.
With the policy set to \c NEW, the reference reaches the generated script and is
expanded when that script runs.
 
A forwarded value that contains an invalid backslash escape will fail
at command invocation while the policy is unset or \c OLD.
An \c{AUTHOR_WARNING} is emitted referencing this policy before the error is
reported by CMake.
 
\qtpolicydeprecatedbehavior
 
\sa qt_policy(), {Qt CMake policies}, qt_generate_deploy_script(),
    qt_generate_deploy_app_script()
 
*/