FileAPI: Add "multiConfig" parameter to index file

Help/manual/cmake-file-api.7.rst

@@ -199,6 +199,7 @@ The reply index file contains a JSON object:
         "root": "/prefix/share/cmake-3.14"
       },
       "generator": {
+        "multiConfig": false,
         "name": "Unix Makefiles"
       }
     },
@@ -267,6 +268,9 @@ The members are:
     A JSON object describing the CMake generator used for the build.
     It has members:
 
+    ``multiConfig``
+      A boolean specifying whether the generator supports multiple output
+      configurations.
     ``name``
       A string specifying the name of the generator.
     ``platform``

Help/release/dev/fileapi-multi-config.rst

@@ -0,0 +1,6 @@
+fileapi-multi-config
+--------------------
+
+* The :manual:`file API <cmake-file-api(7)>` index file now emits a
+  ``multiConfig`` flag specifying whether or not the generator supports
+  multiple output configurations.

Source/cmGlobalGenerator.cxx

@@ -124,6 +124,7 @@ Json::Value cmGlobalGenerator::GetJson() const
 {
   Json::Value generator = Json::objectValue;
   generator["name"] = this->GetName();
+  generator["multiConfig"] = this->IsMultiConfig();
   return generator;
 }
 #endif

Tests/RunCMake/FileAPI/check_index.py

@@ -109,10 +109,11 @@ def check_cmake_generator(g):
     name = g.get("name", None)
     assert is_string(name)
     if name.startswith("Visual Studio"):
-        assert sorted(g.keys()) == ["name", "platform"]
+        assert sorted(g.keys()) == ["multiConfig", "name", "platform"]
         assert is_string(g["platform"])
     else:
-        assert sorted(g.keys()) == ["name"]
+        assert sorted(g.keys()) == ["multiConfig", "name"]
+    assert is_bool(g["multiConfig"], matches(name, "^(Visual Studio |Xcode$)"))
 
 def check_index_object(indexEntry, kind, major, minor, check):
     assert is_dict(indexEntry)