CPack/Deb prevent accidental component dependencies

Prevent accidental inter component dependency setting
since this is a breaking feature in situations where
another CPack module is already using the feature.
It should be enabled if desired since it can cause
issues when upgrading only one of the components
for e.g. configuration instead of all the components
at once.

Help/release/dev/cpack-deb-imporvements.rst

@@ -11,7 +11,8 @@ cpack-deb-imporvements
 * The :module:`CPackDeb` module learned how to generate dependencies between
   Debian packages if multi-component setup is used and
   :variable:`CPACK_COMPONENT_<compName>_DEPENDS` variables are set.
-  This breaks compatibility with previous versions.
+  For backward compatibility this feature is disabled by default. See
+  :variable:`CPACK_DEBIAN_ENABLE_COMPONENT_DEPENDS`.
 
 * The :module:`CPackDeb` module learned how to set the package release number
   (``DebianRevisionNumber`` in package file name).  See

Modules/CPackDeb.cmake

@@ -100,6 +100,13 @@
 #
 #    set(CPACK_DEBIAN_PACKAGE_DEPENDS "libc6 (>= 2.3.1-6), libc6 (< 2.4)")
 #
+# .. variable:: CPACK_DEBIAN_ENABLE_COMPONENT_DEPENDS
+#
+#  Sets inter component dependencies if listed with
+#  :variable:`CPACK_COMPONENT_<compName>_DEPENDS` variables.
+#
+#  * Mandatory : NO
+#  * Default   : -
 #
 # .. variable:: CPACK_DEBIAN_PACKAGE_MAINTAINER
 #
@@ -713,6 +720,8 @@ function(cpack_deb_prepare_package_vars)
         endif()
       endif()
     endforeach()
+
+    if(CPACK_DEBIAN_ENABLE_COMPONENT_DEPENDS)
       set(COMPONENT_DEPENDS "")
       foreach (_PACK ${CPACK_COMPONENT_${_local_component_name}_DEPENDS})
         get_component_package_name(_PACK_NAME "${_PACK}")
@@ -730,6 +739,7 @@ function(cpack_deb_prepare_package_vars)
         endif()
       endif()
     endif()
+  endif()
 
   # at this point, the CPACK_DEBIAN_PACKAGE_DEPENDS is properly set
   # to the minimal dependency of the package

Tests/CPackComponentsDEB/MyLibCPackConfig-components-depend1.cmake.in

@@ -4,6 +4,7 @@
 
 if(CPACK_GENERATOR MATCHES "DEB")
    set(CPACK_DEB_COMPONENT_INSTALL "ON")
+   set(CPACK_DEBIAN_ENABLE_COMPONENT_DEPENDS "ON")
 endif()
 
 #

Tests/CPackComponentsDEB/MyLibCPackConfig-components-depend2.cmake.in

@@ -4,6 +4,7 @@
 
 if(CPACK_GENERATOR MATCHES "DEB")
    set(CPACK_DEB_COMPONENT_INSTALL "ON")
+   set(CPACK_DEBIAN_ENABLE_COMPONENT_DEPENDS "ON")
 endif()
 
 #