implement target kind moduleonly

14 files changed, 351 insertions, 130 deletions

diff --git a/tests/projects/c++/modules/link_order/xmake.lua b/tests/projects/c++/modules/link_order/xmake.lua
index 1ae6639bb..5c7b8a236 100644
--- a/tests/projects/c++/modules/link_order/xmake.lua
+++ b/tests/projects/c++/modules/link_order/xmake.lua
@@ -3,14 +3,14 @@ set_languages("c++20")
 
 target("foo")
     add_rules("c++")
-    set_kind("headeronly")
-    add_rules("c++.moduleonly")
+    set_kind("moduleonly")
+    
     add_files("src/foo.mpp")
 
 target("bar")
     add_rules("c++")
-    set_kind("headeronly")
-    add_rules("c++.moduleonly")
+    set_kind("moduleonly")
+    
     add_files("src/bar.mpp")
 
 target("link_order_1")
diff --git a/tests/projects/c++/modules/moduleonly/xmake.lua b/tests/projects/c++/modules/moduleonly/xmake.lua
index c6cb7cef4..54c681cc8 100644
--- a/tests/projects/c++/modules/moduleonly/xmake.lua
+++ b/tests/projects/c++/modules/moduleonly/xmake.lua
@@ -2,6 +2,5 @@ add_rules("mode.release", "mode.debug")
 set_languages("c++20")
 
 target("mod")
-    set_kind("headeronly")
-    add_rules("c++.moduleonly")
+    set_kind("moduleonly")
     add_files("src/mod.mpp")
diff --git a/tests/projects/c++/modules/packages/my-repo/packages/b/bar2/src/xmake.lua b/tests/projects/c++/modules/packages/my-repo/packages/b/bar2/src/xmake.lua
index 9312aee2d..905c38a02 100644
--- a/tests/projects/c++/modules/packages/my-repo/packages/b/bar2/src/xmake.lua
+++ b/tests/projects/c++/modules/packages/my-repo/packages/b/bar2/src/xmake.lua
@@ -2,6 +2,6 @@ add_rules("mode.release", "mode.debug")
 set_languages("c++20")
 
 target("bar2")
-    set_kind("headeronly")
-    add_rules("c++.moduleonly")
+    set_kind("moduleonly")
+    
     add_files("*.mpp")
diff --git a/tests/projects/c++/modules/packages/my-repo/packages/b/bar2/xmake.lua b/tests/projects/c++/modules/packages/my-repo/packages/b/bar2/xmake.lua
index e56cdaf43..343a52e02 100644
--- a/tests/projects/c++/modules/packages/my-repo/packages/b/bar2/xmake.lua
+++ b/tests/projects/c++/modules/packages/my-repo/packages/b/bar2/xmake.lua
@@ -1,5 +1,5 @@
 package("bar2")
-    set_kind("headeronly")
+    set_kind("moduleonly")
     set_sourcedir(path.join(os.scriptdir(), "src"))
 
     on_install(function(package)
diff --git a/tests/projects/c++/modules/user_headerunit2/a/xmake.lua b/tests/projects/c++/modules/user_headerunit2/a/xmake.lua
index 261428921..8d9a4cb8b 100644
--- a/tests/projects/c++/modules/user_headerunit2/a/xmake.lua
+++ b/tests/projects/c++/modules/user_headerunit2/a/xmake.lua
@@ -1,6 +1,6 @@
 target("a")

     set_languages("cxxlatest")

-    set_kind("headeronly")

-    add_rules("c++.moduleonly")

+    set_kind("moduleonly")

+    

     add_headerfiles("*.hpp")

     add_files("a.mpp")

diff --git a/tests/projects/c++/modules/user_headerunit2/b/xmake.lua b/tests/projects/c++/modules/user_headerunit2/b/xmake.lua
index 9821fcd6d..5be8ae50b 100644
--- a/tests/projects/c++/modules/user_headerunit2/b/xmake.lua
+++ b/tests/projects/c++/modules/user_headerunit2/b/xmake.lua
@@ -1,6 +1,6 @@
 target("b")

     add_deps("a")

     set_languages("cxxlatest")

-    set_kind("headeronly")

-    add_rules("c++.moduleonly")

+    set_kind("moduleonly")

+    

     add_files("b.mpp")

diff --git a/xmake/actions/build/build.lua b/xmake/actions/build/build.lua
index bb0b61cc1..1db197cd6 100644
--- a/xmake/actions/build/build.lua
+++ b/xmake/actions/build/build.lua
@@ -65,7 +65,7 @@ function _add_batchjobs_builtin(batchjobs, rootjob, target)
     end
 
     -- uses the builtin target script
-    if not job and (target:is_static() or target:is_binary() or target:is_shared() or target:is_object()) then
+    if not job and (target:is_static() or target:is_binary() or target:is_shared() or target:is_object() or target:is_moduleonly()) then
         job, job_leaf = import("kinds." .. target:kind(), {anonymous = true})(batchjobs, rootjob, target)
     end
     job = job or rootjob
diff --git a/xmake/actions/build/kinds/moduleonly.lua b/xmake/actions/build/kinds/moduleonly.lua
new file mode 100644
index 000000000..1a5997712
--- /dev/null
+++ b/xmake/actions/build/kinds/moduleonly.lua
@@ -0,0 +1,257 @@
+--!A cross-platform build utility based on Lua
+--
+-- Licensed under the Apache License, Version 2.0 (the "License");
+-- you may not use this file except in compliance with the License.
+-- You may obtain a copy of the License at
+--
+--     http://www.apache.org/licenses/LICENSE-2.0
+--
+-- Unless required by applicable law or agreed to in writing, software
+-- distributed under the License is distributed on an "AS IS" BASIS,
+-- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+-- See the License for the specific language governing permissions and
+-- limitations under the License.
+--
+-- Copyright (C) 2015-present, TBOOX Open Source Group.
+--
+-- @author      ruki, Arthapz
+-- @file        modules.lua
+--
+
+-- imports
+import("core.base.option")
+import("core.project.rule")
+import("core.project.config")
+import("core.project.project")
+import("async.runjobs")
+import("private.utils.batchcmds")
+import("private.utils.rule_groups")
+
+-- has scripts for the custom rule
+function _has_scripts_for_rule(ruleinst, suffix)
+
+    -- add batch jobs for xx_build_files
+    local scriptname = "build_files" .. (suffix and ("_" .. suffix) or "")
+    local script = ruleinst:script(scriptname)
+    if script then
+        return true
+    end
+
+    -- add batch jobs for xx_build_file
+    scriptname = "build_file" .. (suffix and ("_" .. suffix) or "")
+    script = ruleinst:script(scriptname)
+    if script then
+        return true
+    end
+
+    -- add batch jobs for xx_buildcmd_files
+    scriptname = "buildcmd_files" .. (suffix and ("_" .. suffix) or "")
+    script = ruleinst:script(scriptname)
+    if script then
+        return true
+    end
+
+    -- add batch jobs for xx_buildcmd_file
+    scriptname = "buildcmd_file" .. (suffix and ("_" .. suffix) or "")
+    script = ruleinst:script(scriptname)
+    if script then
+        return true
+    end
+end
+
+-- has scripts for target
+function _has_scripts_for_target(target, suffix)
+    local scriptname = "build_files" .. (suffix and ("_" .. suffix) or "")
+    local script = target:script(scriptname)
+    if script then
+        return true
+    else
+        scriptname = "build_file" .. (suffix and ("_" .. suffix) or "")
+        script = target:script(scriptname)
+        if script then
+            return true
+        end
+    end
+end
+
+-- has scripts for group
+function _has_scripts_for_group(group, suffix)
+    for _, item in pairs(group) do
+        if item.target and _has_scripts_for_target(item.target, suffix) then
+            return true
+        end
+        if item.rule and _has_scripts_for_rule(item.rule, suffix) then
+            return true
+        end
+    end
+end
+
+-- add batch jobs for the custom rule
+function _add_batchjobs_for_rule(batchjobs, rootjob, target, sourcebatch, suffix)
+
+    -- get rule
+    local rulename = assert(sourcebatch.rulename, "unknown rule for sourcebatch!")
+    local ruleinst = rule_groups.get_rule(target, rulename)
+
+    -- add batch jobs for xx_build_files
+    local scriptname = "build_files" .. (suffix and ("_" .. suffix) or "")
+    local script = ruleinst:script(scriptname)
+    if script then
+        if ruleinst:extraconf(scriptname, "batch") then
+            script(target, batchjobs, sourcebatch, {rootjob = rootjob, distcc = ruleinst:extraconf(scriptname, "distcc")})
+        else
+            batchjobs:addjob("rule/" .. rulename .. "/" .. scriptname, function (index, total)
+                script(target, sourcebatch, {progress = (index * 100) / total})
+            end, {rootjob = rootjob})
+        end
+    end
+
+    -- add batch jobs for xx_build_file
+    if not script then
+        scriptname = "build_file" .. (suffix and ("_" .. suffix) or "")
+        script = ruleinst:script(scriptname)
+        if script then
+            local sourcekind = sourcebatch.sourcekind
+            for _, sourcefile in ipairs(sourcebatch.sourcefiles) do
+                batchjobs:addjob(sourcefile, function (index, total)
+                    script(target, sourcefile, {sourcekind = sourcekind, progress = (index * 100) / total})
+                end, {rootjob = rootjob, distcc = ruleinst:extraconf(scriptname, "distcc")})
+            end
+        end
+    end
+
+    -- add batch jobs for xx_buildcmd_files
+    if not script then
+        scriptname = "buildcmd_files" .. (suffix and ("_" .. suffix) or "")
+        script = ruleinst:script(scriptname)
+        if script then
+            batchjobs:addjob("rule/" .. rulename .. "/" .. scriptname, function (index, total)
+                local batchcmds_ = batchcmds.new({target = target})
+                local distcc = ruleinst:extraconf(scriptname, "distcc")
+                script(target, batchcmds_, sourcebatch, {progress = (index * 100) / total, distcc = distcc})
+                batchcmds_:runcmds({changed = target:is_rebuilt(), dryrun = option.get("dry-run")})
+            end, {rootjob = rootjob})
+        end
+    end
+
+    -- add batch jobs for xx_buildcmd_file
+    if not script then
+        scriptname = "buildcmd_file" .. (suffix and ("_" .. suffix) or "")
+        script = ruleinst:script(scriptname)
+        if script then
+            local sourcekind = sourcebatch.sourcekind
+            for _, sourcefile in ipairs(sourcebatch.sourcefiles) do
+                batchjobs:addjob(sourcefile, function (index, total)
+                    local batchcmds_ = batchcmds.new({target = target})
+                    script(target, batchcmds_, sourcefile, {sourcekind = sourcekind, progress = (index * 100) / total})
+                    batchcmds_:runcmds({changed = target:is_rebuilt(), dryrun = option.get("dry-run")})
+                end, {rootjob = rootjob, distcc = ruleinst:extraconf(scriptname, "distcc")})
+            end
+        end
+    end
+end
+
+-- add batch jobs for target
+function _add_batchjobs_for_target(batchjobs, rootjob, target, sourcebatch, suffix)
+    -- we just build sourcebatch with on_build_files scripts
+    --
+    -- for example, c++.build and c++.build.modules.builder rules have same sourcefiles,
+    -- but we just build it for c++.build
+    --
+    -- @see https://github.com/xmake-io/xmake/issues/3171
+    --
+    local rulename = sourcebatch.rulename
+    if rulename then
+        local ruleinst = rule_groups.get_rule(target, rulename)
+        if not ruleinst:script("build_file") and
+            not ruleinst:script("build_files") then
+            return
+        end
+    end
+
+    -- add batch jobs
+    local scriptname = "build_files" .. (suffix and ("_" .. suffix) or "")
+    local script = target:script(scriptname)
+    if script then
+        if target:extraconf(scriptname, "batch") then
+            script(target, batchjobs, sourcebatch, {rootjob = rootjob, distcc = target:extraconf(scriptname, "distcc")})
+        else
+            batchjobs:addjob(target:name() .. "/" .. scriptname, function (index, total)
+                script(target, sourcebatch, {progress = (index * 100) / total})
+            end, {rootjob = rootjob})
+        end
+        return true
+    else
+        scriptname = "build_file" .. (suffix and ("_" .. suffix) or "")
+        script = target:script(scriptname)
+        if script then
+            local sourcekind = sourcebatch.sourcekind
+            for _, sourcefile in ipairs(sourcebatch.sourcefiles) do
+                batchjobs:addjob(sourcefile, function (index, total)
+                    script(target, sourcefile, {sourcekind = sourcekind, progress = (index * 100) / total})
+                end, {rootjob = rootjob, distcc = target:extraconf(scriptname, "distcc")})
+            end
+            return true
+        end
+    end
+end
+
+-- add batch jobs for group
+function _add_batchjobs_for_group(batchjobs, rootjob, target, group, suffix)
+    for _, item in pairs(group) do
+        local sourcebatch = item.sourcebatch
+        if item.target then
+            _add_batchjobs_for_target(batchjobs, rootjob, target, sourcebatch, suffix)
+        end
+        -- override on_xxx script in target? we need to ignore rule scripts
+        if item.rule and (suffix or not _has_scripts_for_target(target, suffix)) then
+            _add_batchjobs_for_rule(batchjobs, rootjob, target, sourcebatch, suffix)
+        end
+    end
+end
+
+-- add batch jobs for building source files
+function add_batchjobs_for_sourcefiles(batchjobs, rootjob, target, sourcebatches)
+
+    -- build sourcebatch groups first
+    local groups = rule_groups.build_sourcebatch_groups(target, sourcebatches)
+
+    -- add batch jobs for build_after
+    local groups_root
+    local groups_leaf = rootjob
+    for idx, group in ipairs(groups) do
+        if _has_scripts_for_group(group, "after") then
+            batchjobs:group_enter(target:name() .. "/after_build_files" .. idx)
+            _add_batchjobs_for_group(batchjobs, groups_leaf, target, group, "after")
+            groups_leaf = batchjobs:group_leave() or groups_leaf
+            groups_root = groups_root or groups_leaf
+        end
+    end
+
+    -- add batch jobs for build
+    for idx, group in ipairs(groups) do
+        if _has_scripts_for_group(group) then
+            batchjobs:group_enter(target:name() .. "/build_files" .. idx)
+            _add_batchjobs_for_group(batchjobs, groups_leaf, target, group)
+            groups_leaf = batchjobs:group_leave() or groups_leaf
+            groups_root = groups_root or groups_leaf
+        end
+    end
+
+    -- add batch jobs for build_before
+    for idx, group in ipairs(groups) do
+        if _has_scripts_for_group(group, "before") then
+            batchjobs:group_enter(target:name() .. "/before_build_files" .. idx)
+            _add_batchjobs_for_group(batchjobs, groups_leaf, target, group, "before")
+            groups_leaf = batchjobs:group_leave() or groups_leaf
+            groups_root = groups_root or groups_leaf
+        end
+    end
+    return groups_leaf, groups_root or groups_leaf
+end
+
+-- add batch jobs for generating modules deps files
+function main(batchjobs, rootjob, target)
+    return add_batchjobs_for_sourcefiles(batchjobs, rootjob, target, target:sourcebatches())
+end
+
diff --git a/xmake/core/project/target.lua b/xmake/core/project/target.lua
index 8cc2ff824..b6835a277 100644
--- a/xmake/core/project/target.lua
+++ b/xmake/core/project/target.lua
@@ -1201,9 +1201,14 @@ function _instance:is_headeronly()
     return self:kind() == "headeronly"
 end
 
+-- is moduleonly target?
+function _instance:is_moduleonly()
+    return self:kind() == "moduleonly"
+end
+
 -- is library target?
 function _instance:is_library()
-    return self:is_static() or self:is_shared() or self:is_headeronly()
+    return self:is_static() or self:is_shared() or self:is_headeronly() or self:is_moduleonly()
 end
 
 -- is default target?
@@ -1555,7 +1560,7 @@ end
 function _instance:filename()
 
     -- no target file?
-    if self:is_object() or self:is_phony() or self:is_headeronly() then
+    if self:is_object() or self:is_phony() or self:is_headeronly() or self:is_moduleonly() then
         return
     end
 
diff --git a/xmake/modules/private/check/checkers/api/target/kind.lua b/xmake/modules/private/check/checkers/api/target/kind.lua
index 127f78ad5..5d716b129 100644
--- a/xmake/modules/private/check/checkers/api/target/kind.lua
+++ b/xmake/modules/private/check/checkers/api/target/kind.lua
@@ -23,5 +23,5 @@ import(".api_checker")
 
 function main(opt)
     opt = opt or {}
-    api_checker.check_targets("kind", table.join(opt, {values = {"object", "binary", "static", "shared", "headeronly", "phony"}}))
+    api_checker.check_targets("kind", table.join(opt, {values = {"object", "binary", "static", "shared", "headeronly", "moduleonly", "phony"}}))
 end
diff --git a/xmake/plugins/project/cmake/cmakelists.lua b/xmake/plugins/project/cmake/cmakelists.lua
index 6fcf38313..a91328d54 100644
--- a/xmake/plugins/project/cmake/cmakelists.lua
+++ b/xmake/plugins/project/cmake/cmakelists.lua
@@ -1003,6 +1003,8 @@ function _add_target(cmakelists, target, outputdir)
         _add_target_headeronly(cmakelists, target)
         _add_target_include_directories(cmakelists, target, outputdir)
         return
+    elseif targetkind == 'moduleonly' then
+        raise("target kind moduleonly is currently not supported for cmakelists")
     else
         raise("unknown target kind %s", target:kind())
     end
diff --git a/xmake/rules/c++/modules/modules_support/compiler_support.lua b/xmake/rules/c++/modules/modules_support/compiler_support.lua
index d7e8a0bd8..d9d849454 100644
--- a/xmake/rules/c++/modules/modules_support/compiler_support.lua
+++ b/xmake/rules/c++/modules/modules_support/compiler_support.lua
@@ -116,14 +116,14 @@ end
 -- this target contains module files?
 function contains_modules(target)
     -- we can not use `"c++.build.builder"`, because it contains sourcekind/cxx.
-    local target_with_modules = (target:sourcebatches()["c++.moduleonly"] or target:sourcebatches()["c++.build.modules"]) and true or false
+    local target_with_modules = target:sourcebatches()["c++.build.modules"] and true or false
     if not target_with_modules then
         target_with_modules = target:policy("build.c++.modules")
     end
     if not target_with_modules then
         for _, dep in ipairs(target:orderdeps()) do
             local sourcebatches = dep:sourcebatches()
-            if sourcebatches["c++.moduleonly"] or sourcebatches["c++.build.modules"] then
+            if sourcebatches["c++.build.modules"] then
                 target_with_modules = true
                 break
             end
diff --git a/xmake/rules/c++/modules/modules_support/dependency_scanner.lua b/xmake/rules/c++/modules/modules_support/dependency_scanner.lua
index e4e6783bd..0b02292ef 100644
--- a/xmake/rules/c++/modules/modules_support/dependency_scanner.lua
+++ b/xmake/rules/c++/modules/modules_support/dependency_scanner.lua
@@ -438,7 +438,7 @@ end
 function get_targetdeps_modules(target)
     local sourcefiles
     for _, dep in ipairs(target:orderdeps()) do
-        local sourcebatch = dep:sourcebatches()["c++.moduleonly"] or dep:sourcebatches()["c++.build.modules.builder"]
+        local sourcebatch = dep:sourcebatches()["c++.build.modules.builder"]
         if sourcebatch and sourcebatch.sourcefiles then
             for _, sourcefile in ipairs(sourcebatch.sourcefiles) do
                 local fileconfig = dep:fileconfig(sourcefile)
diff --git a/xmake/rules/c++/modules/xmake.lua b/xmake/rules/c++/modules/xmake.lua
index 34d636ca1..13fb405d8 100644
--- a/xmake/rules/c++/modules/xmake.lua
+++ b/xmake/rules/c++/modules/xmake.lua
@@ -54,8 +54,8 @@ rule("c++.build.modules")
             target:data_set("cxx.has_modules", true)
 
             -- moduleonly modules are implicitly public
-            if target:rule("c++.moduleonly") then
-                local sourcebatch = target:sourcebatches()["c++.moduleonly"]
+            if target:is_moduleonly() then
+                local sourcebatch = target:sourcebatches()["c++.build.modules.builder"]
                 for _, sourcefile in ipairs(sourcebatch.sourcefiles) do
                     target:fileconfig_add(sourcefile, {public = true})
                 end
@@ -70,43 +70,43 @@ rule("c++.build.modules.builder")
 
     -- parallel build support to accelerate `xmake build` to build modules
     before_build_files(function(target, batchjobs, sourcebatch, opt)
-        if not target:rule("c++.moduleonly") then
-            if target:data("cxx.has_modules") then
-                import("modules_support.compiler_support")
-                import("modules_support.dependency_scanner")
-                import("modules_support.builder")
+        if target:data("cxx.has_modules") then
+            import("modules_support.compiler_support")
+            import("modules_support.dependency_scanner")
+            import("modules_support.builder")
 
-                -- add target deps modules
-                if target:orderdeps() then
-                    local deps_sourcefiles = dependency_scanner.get_targetdeps_modules(target)
-                    if deps_sourcefiles then
-                        table.join2(sourcebatch.sourcefiles, deps_sourcefiles)
-                    end
+            -- add target deps modules
+            if target:orderdeps() then
+                local deps_sourcefiles = dependency_scanner.get_targetdeps_modules(target)
+                if deps_sourcefiles then
+                    table.join2(sourcebatch.sourcefiles, deps_sourcefiles)
                 end
+            end
 
-                -- append std module
-                local std_modules = compiler_support.get_stdmodules(target)
-                if std_modules then
-                    table.join2(sourcebatch.sourcefiles, std_modules)
-                    target:fileconfig_set(std_modules[1], {external = true})
-                    target:fileconfig_set(std_modules[2], {external = true})
-                end
+            -- append std module
+            local std_modules = compiler_support.get_stdmodules(target)
+            if std_modules then
+                table.join2(sourcebatch.sourcefiles, std_modules)
+                target:fileconfig_set(std_modules[1], {external = true})
+                target:fileconfig_set(std_modules[2], {external = true})
+            end
 
-                -- extract packages modules dependencies
-                local package_modules_data = dependency_scanner.get_all_packages_modules(target, opt)
-                if package_modules_data then
-                    -- append to sourcebatch
-                    for _, package_module_data in table.orderpairs(package_modules_data) do
-                        table.insert(sourcebatch.sourcefiles, package_module_data.file)
-                        target:fileconfig_set(package_module_data.file, {external = true, defines = package_module_data.metadata.defines})
-                    end
+            -- extract packages modules dependencies
+            local package_modules_data = dependency_scanner.get_all_packages_modules(target, opt)
+            if package_modules_data then
+                -- append to sourcebatch
+                for _, package_module_data in table.orderpairs(package_modules_data) do
+                    table.insert(sourcebatch.sourcefiles, package_module_data.file)
+                    target:fileconfig_set(package_module_data.file, {external = true, defines = package_module_data.metadata.defines})
                 end
+            end
 
-                opt.batchjobs = true
+            opt.batchjobs = true
 
-                compiler_support.patch_sourcebatch(target, sourcebatch, opt)
-                local modules = dependency_scanner.get_module_dependencies(target, sourcebatch, opt)
+            compiler_support.patch_sourcebatch(target, sourcebatch, opt)
+            local modules = dependency_scanner.get_module_dependencies(target, sourcebatch, opt)
 
+            if not target:is_moduleonly() then
                 -- avoid building non referenced modules
                 sourcebatch.objectfiles = dependency_scanner.sort_modules_by_dependencies(target, sourcebatch.objectfiles, modules)
 
@@ -118,58 +118,57 @@ rule("c++.build.modules.builder")
 
                 -- cull external modules objectfile
                 compiler_support.cull_objectfiles(target, modules, sourcebatch)
-                compiler_support.localcache():set2(target:name(), "c++.modules", modules)
-                compiler_support.localcache():save()
             else
-                -- avoid duplicate linking of object files of non-module programs
                 sourcebatch.objectfiles = {}
             end
+
+            compiler_support.localcache():set2(target:name(), "c++.modules", modules)
+            compiler_support.localcache():save()
         else
-            sourcebatch.sourcefiles = {}
+            -- avoid duplicate linking of object files of non-module programs
             sourcebatch.objectfiles = {}
-            sourcebatch.dependfiles = {}
         end
     end, {batch = true})
 
     -- serial compilation only, usually used to support project generator
     before_buildcmd_files(function(target, batchcmds, sourcebatch, opt)
-        if not target:rule("c++.moduleonly") then
-            if target:data("cxx.has_modules") then
-                import("modules_support.compiler_support")
-                import("modules_support.dependency_scanner")
-                import("modules_support.builder")
+        if target:data("cxx.has_modules") then
+            import("modules_support.compiler_support")
+            import("modules_support.dependency_scanner")
+            import("modules_support.builder")
 
-                -- add target deps modules
-                if target:orderdeps() then
-                    local deps_sourcefiles = dependency_scanner.get_targetdeps_modules(target)
-                    if deps_sourcefiles then
-                        table.join2(sourcebatch.sourcefiles, deps_sourcefiles)
-                    end
+            -- add target deps modules
+            if target:orderdeps() then
+                local deps_sourcefiles = dependency_scanner.get_targetdeps_modules(target)
+                if deps_sourcefiles then
+                    table.join2(sourcebatch.sourcefiles, deps_sourcefiles)
                 end
+            end
 
-                -- append std module
-                local std_modules = compiler_support.get_stdmodules(target)
-                if std_modules then
-                    table.join2(sourcebatch.sourcefiles, std_modules)
-                    target:fileconfig_set(std_modules[1], {external = true})
-                    target:fileconfig_set(std_modules[2], {external = true})
-                end
+            -- append std module
+            local std_modules = compiler_support.get_stdmodules(target)
+            if std_modules then
+                table.join2(sourcebatch.sourcefiles, std_modules)
+                target:fileconfig_set(std_modules[1], {external = true})
+                target:fileconfig_set(std_modules[2], {external = true})
+            end
 
-                -- extract packages modules dependencies
-                local package_modules_data = dependency_scanner.get_all_packages_modules(target, opt)
-                if package_modules_data then
-                    -- append to sourcebatch
-                    for _, package_module_data in table.orderpairs(package_modules_data) do
-                        table.insert(sourcebatch.sourcefiles, package_module_data.file)
-                        target:fileconfig_set(package_module_data.file, {external = true, defines = package_module_data.metadata.defines})
-                    end
+            -- extract packages modules dependencies
+            local package_modules_data = dependency_scanner.get_all_packages_modules(target, opt)
+            if package_modules_data then
+                -- append to sourcebatch
+                for _, package_module_data in table.orderpairs(package_modules_data) do
+                    table.insert(sourcebatch.sourcefiles, package_module_data.file)
+                    target:fileconfig_set(package_module_data.file, {external = true, defines = package_module_data.metadata.defines})
                 end
+            end
 
-                opt.batchjobs = false
+            opt.batchjobs = false
 
-                compiler_support.patch_sourcebatch(target, sourcebatch, opt)
-                local modules = dependency_scanner.get_module_dependencies(target, sourcebatch, opt)
+            compiler_support.patch_sourcebatch(target, sourcebatch, opt)
+            local modules = dependency_scanner.get_module_dependencies(target, sourcebatch, opt)
 
+            if not target:is_moduleonly() then
                 -- avoid building non referenced modules
                 sourcebatch.objectfiles = dependency_scanner.sort_modules_by_dependencies(target, sourcebatch.objectfiles, modules)
 
@@ -181,12 +180,13 @@ rule("c++.build.modules.builder")
 
                 -- cull external modules objectfile
                 compiler_support.cull_objectfiles(target, modules, sourcebatch)
-                compiler_support.localcache():set2(target:name(), "c++.modules", modules)
-                compiler_support.localcache():save()
             else
                 -- avoid duplicate linking of object files of non-module programs
                 sourcebatch.objectfiles = {}
             end
+
+            compiler_support.localcache():set2(target:name(), "c++.modules", modules)
+            compiler_support.localcache():save()
         else
             sourcebatch.sourcefiles = {}
             sourcebatch.objectfiles = {}
@@ -211,48 +211,6 @@ rule("c++.build.modules.builder")
         end
     end)
 
--- moduleonly
-rule("c++.moduleonly")
-    add_deps("c++.build.modules.install")
-    set_extensions(".mpp", ".mxx", ".cppm", ".ixx", ".cpp")
-
-    before_build(function(target)
-        if target:data("cxx.has_modules") then
-            import("modules_support.compiler_support")
-            import("modules_support.dependency_scanner")
-
-            local sourcebatch = target:sourcebatches()["c++.moduleonly"]
-
-            -- add target deps modules
-            if target:orderdeps() then
-                local deps_sourcefiles = dependency_scanner.get_targetdeps_modules(target)
-                if deps_sourcefiles then
-                    table.join2(sourcebatch.sourcefiles, deps_sourcefiles)
-                end
-            end
-
-            -- append std module
-            table.join2(sourcebatch.sourcefiles, compiler_support.get_stdmodules(target) or {})
-
-            -- extract packages modules dependencies
-            local package_modules_data = dependency_scanner.get_all_packages_modules(target, opt)
-            if package_modules_data then
-                -- append to sourcebatch
-                for _, package_module_data in table.orderpairs(package_modules_data) do
-                    table.insert(sourcebatch.sourcefiles, package_module_data.file)
-                    target:fileconfig_add(package_module_data.file, {external = true, defines = package_module_data.metadata.defines})
-                end
-            end
-
-            local opt = {batchjobs = true}
-
-            compiler_support.patch_sourcebatch(target, sourcebatch, opt)
-            local modules = dependency_scanner.get_module_dependencies(target, sourcebatch, opt)
-            compiler_support.localcache():set2(target:name(), "c++.modules", modules)
-            compiler_support.localcache():save()
-        end
-    end)
-
 -- install modules
 rule("c++.build.modules.install")
     set_extensions(".mpp", ".mxx", ".cppm", ".ixx")
@@ -266,7 +224,7 @@ rule("c++.build.modules.install")
         if compiler_support.contains_modules(target) then
             local modules = compiler_support.localcache():get2(target:name(), "c++.modules")
             builder.generate_metadata(target, modules)
-  
+
             compiler_support.install_module_target(target)
         end
     end)