add compatibility.version policy #5527

xmake/core/project/policy.lua

@@ -149,13 +149,25 @@ function policy.policies()
             ["diagnosis.check_build_deps"]        = {description = "Show diagnosis info for checking build dependencies", default = false, type = "boolean"},
             -- Set the network mode, e.g. public/private
             --   private: it will disable fetch remote package repositories
-            ["network.mode"]                      = {description = "Set the network mode", type = "string"}
+            ["network.mode"]                      = {description = "Set the network mode", type = "string"},
+            -- Set the compatibility version, e.g. 2.0, 3.0
+            ["compatibility.version"]             = {description = "Set the compatibility version", type = "string"}
         }
         policy._POLICIES = policies
     end
     return policies
 end
 
+-- set policy default value
+function policy.set_default(name, value)
+    local defined_policy = policy.policies()[name]
+    if defined_policy then
+        defined_policy.default = value
+    else
+        os.raise("unknown policy(%s)!", name)
+    end
+end
+
 -- check policy value
 function policy.check(name, value)
     local defined_policy = policy.policies()[name]

xmake/core/project/project.lua

@@ -32,6 +32,7 @@ local global                = require("base/global")
 local process               = require("base/process")
 local hashset               = require("base/hashset")
 local baseoption            = require("base/option")
+local semver                = require("base/semver")
 local deprecated            = require("base/deprecated")
 local interpreter           = require("base/interpreter")
 local instance_deps         = require("base/private/instance_deps")
@@ -819,11 +820,32 @@ function project.version()
     return project.get("target.version")
 end
 
+-- init default policies
+-- @see https://github.com/xmake-io/xmake/issues/5527
+function project._init_default_policies()
+    local compatibility_version = project.policy("compatibility.version")
+    if compatibility_version then
+        if semver.compare(compatibility_version, "3.0") >= 0 then
+            policy.set_default("package.cmake_generator.ninja", true)
+        else
+            policy.set_default("package.cmake_generator.ninja", false)
+        end
+    end
+end
+
 -- get the project policy, the root policy of the target scope
 function project.policy(name)
     local policies = project._memcache():get("policies")
     if not policies then
 
+        -- init default policies
+        if name ~= "compatibility.version" then
+            if not project._DEFAULT_POLICIES_INITED then
+                project._init_default_policies()
+                project._DEFAULT_POLICIES_INITED = true
+            end
+        end
+
         -- get policies from project, e.g. set_policy("xxx", true)
         policies = project.get("target.policy")