fix(conan): Properly inspect null values

This is a fixup for 802dfa8.

Signed-off-by: Sebastian Schuberth <[email protected]>

plugins/package-managers/conan/src/funTest/assets/projects/synthetic/conan-expected-output-py.yml

@@ -1,6 +1,6 @@
 ---
 project:
-  id: "Conan::poco:null"
+  id: "Conan::poco:"
   definition_file_path: "plugins/package-managers/conan/src/funTest/assets/projects/synthetic/conan-py/conanfile.py"
   declared_licenses:
   - "BSL-1.0"

plugins/package-managers/conan/src/main/kotlin/Conan.kt

@@ -32,6 +32,7 @@ import java.io.File
 
 import kotlinx.serialization.json.Json
 import kotlinx.serialization.json.JsonObject
+import kotlinx.serialization.json.contentOrNull
 import kotlinx.serialization.json.jsonObject
 import kotlinx.serialization.json.jsonPrimitive
 
@@ -334,7 +335,9 @@ class Conan(
             }
         }
 
-        return results[field]?.jsonPrimitive?.content
+        // Note that while the console output of "conan inspect" uses "None" for absent values, the JSON output actually
+        // uses null values.
+        return results[field]?.jsonPrimitive?.contentOrNull
     }
 
     /**