Do not error out on missing optional repository dependencies

Read the 'required' value from dependencies.yaml and store all required
dependencies of repository 'qtfoo' in a global property
QT_REQUIRED_DEPS_FOR_qtfoo.

Check this property in the top-level CMakeLists.txt and only print
informational messages instead of errors for optional dependencies.

Fixes: QTBUG-91144
Change-Id: I0e1b84a70221857cebba1b9a27456ad3667bfe3a
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

CMakeLists.txt

@@ -49,20 +49,35 @@ qt_internal_sort_module_dependencies("${BUILD_SUBMODULES}" BUILD_SUBMODULES
 foreach(module IN LISTS BUILD_SUBMODULES)
     # Check for unmet dependencies
     if(NOT DEFINED BUILD_${module} OR BUILD_${module})
-        message(NOTICE "Check dependencies of '${module}'")
+        message(NOTICE "Checking dependencies of '${module}'")
+        get_property(required_deps GLOBAL PROPERTY QT_REQUIRED_DEPS_FOR_${module})
         foreach(dep IN LISTS "${qt_module_dependency_map_prefix}${module}")
             if (dep STREQUAL "qtbase")
                 # Always available skip
                 continue()
             endif()
-            if(NOT EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/${dep}/CMakeLists.txt")
+
-                message(FATAL_ERROR "Module '${module}' depends on '${dep}', but ${dep}'s \
+            set(required FALSE)
-                CMakeLists.txt couldn't be found.\nNote: Use '-skip ${module}' to exclude it \
+            if(dep IN_LIST required_deps)
-                from build.\n")
+                set(required TRUE)
             endif()
-            if(DEFINED BUILD_${dep} AND NOT BUILD_${dep})
+
-                message(FATAL_ERROR "Module '${module}' depends on '${dep}', but '${dep}' \
+            set(error_reason "")
-                will not be built.\nNote: Use '-skip ${module}' to exclude it from build.\n")
+            if(NOT EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/${dep}/CMakeLists.txt")
+                set(error_reason "${dep}'s CMakeLists.txt couldn't be found")
+            elseif(DEFINED BUILD_${dep} AND NOT BUILD_${dep})
+                set(error_reason "building '${dep}' was explicitly disabled")
+            endif()
+
+            if(NOT error_reason STREQUAL "")
+                if(required)
+                    message(FATAL_ERROR "Module '${module}' depends on '${dep}', "
+                        "but ${error_reason}.\n"
+                        "Note: Use '-skip ${module}' to exclude it from the build.")
+                else()
+                    message(NOTICE "Skipping optional dependency '${dep}' of '${module}', "
+                        "because ${error_reason}.")
+                endif()
             endif()
         endforeach()
     endif()

cmake/QtTopLevelHelpers.cmake

@@ -17,24 +17,34 @@ endfunction()
 # Each entry will be in the format dependency/sha1
 function(qt_internal_parse_dependencies depends_file out_dependencies)
     file(STRINGS "${depends_file}" lines)
+    set(eof_marker "---EOF---")
+    list(APPEND lines "${eof_marker}")
+    set(required_default TRUE)
     set(dependencies "")
     set(dependency "")
+    set(revision "")
+    set(required "${required_default}")
     foreach(line IN LISTS lines)
-        if(line STREQUAL "dependencies:")
+        if(line MATCHES "^  (.+):$" OR line STREQUAL "${eof_marker}")
-            set(found_dependencies 1)
+            # Found a repo entry or end of file. Add the last seen dependency.
-        elseif(found_dependencies)
+            if(NOT dependency STREQUAL "")
-            if(line MATCHES "^    ref: (.*)$")
+                if(revision STREQUAL "")
-                set(revision "${CMAKE_MATCH_1}")
-                list(APPEND dependencies ${dependency}/${revision})
-                set(dependency "")
-            elseif (line MATCHES "^  (.*):$")
-                if(dependency)
                     message(FATAL_ERROR "Format error in ${depends_file} - ${dependency} does not specify revision!")
                 endif()
+                list(APPEND dependencies "${dependency}/${revision}/${required}")
+            endif()
+            # Remember the current dependency
+            if(NOT line STREQUAL "${eof_marker}")
                 set(dependency "${CMAKE_MATCH_1}")
+                set(revision "")
+                set(required "${required_default}")
                 # dependencies are specified with relative path to this module
                 string(REPLACE "../" "" dependency ${dependency})
             endif()
+        elseif(line MATCHES "^    ref: (.+)$")
+            set(revision "${CMAKE_MATCH_1}")
+        elseif(line MATCHES "^    required: (.+)$")
+            string(TOUPPER "${CMAKE_MATCH_1}" required)
         endif()
     endforeach()
     message(DEBUG "qt_internal_parse_dependencies for ${depends_file}: ${dependencies} ${revisions}")
@@ -66,10 +76,16 @@ function(qt_internal_add_module_dependencies module ordered out_ordered out_has_
     endif()
     set(modules_dependencies "")
     foreach(dependency IN LISTS dependencies)
-        string(FIND "${dependency}" "/" splitindex REVERSE)
+        if(dependency MATCHES "(.*)/([^/]+)/([^/]+)")
-        string(SUBSTRING "${dependency}" ${splitindex} -1 revision)
+            set(dependency "${CMAKE_MATCH_1}")
-        string(SUBSTRING "${revision}" 1 -1 revision)
+            set(revision "${CMAKE_MATCH_2}")
-        string(SUBSTRING "${dependency}" 0 ${splitindex} dependency)
+            set(required "${CMAKE_MATCH_3}")
+            if(required)
+                set_property(GLOBAL APPEND PROPERTY QT_REQUIRED_DEPS_FOR_${module} ${dependency})
+            endif()
+        else()
+            message(FATAL_ERROR "Internal Error: wrong dependency format ${dependency}")
+        endif()
         list(APPEND modules_dependencies "${dependency}")
         list(FIND ordered "${dependency}" dindex)
         if (dindex EQUAL -1)