CMakePresets.json: Properly report macro expansion errors

Make a distinction between strings which simply use the
$vendor{<...>} macro, which is valid but makes it unusable by CMake,
and strings which actually contain invalid macro expansions.

Fixes: #21308

1 files changed, 13 insertions, 0 deletions

diff --git a/Tests/RunCMake/CMakePresets/EmptyEnv.json.in b/Tests/RunCMake/CMakePresets/EmptyEnv.json.in
new file mode 100644
index 0000000..ef0d575
--- /dev/null
+++ b/Tests/RunCMake/CMakePresets/EmptyEnv.json.in
@@ -0,0 +1,13 @@
+{
+  "version": 1,
+  "configurePresets": [
+    {
+      "name": "EmptyEnv",
+      "generator": "@RunCMake_GENERATOR@",
+      "binaryDir": "${sourceDir}/build",
+      "cacheVariables": {
+        "MY_VAR": "$env{}"
+      }
+    }
+  ]
+}