Add check against downgrading proeprties to readonly (#201)

Fixes #199
aws · Aug 26, 2018 · f60b0ac · f60b0ac
1 parent f25c8c4
commit f60b0ac
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Showing 3 changed files with 645 additions and 195 deletions.
diff --git a/packages/jsii/lib/compiler.ts b/packages/jsii/lib/compiler.ts
@@ -1371,6 +1371,11 @@ function validateOverriddenSignatures(mod: spec.Assembly, externalTypes: Map<str
 
                 throw new Error(`${currentFqn}.${currentProperty.name}: type changed from ${orig} (in ${ancestorFqn}) to ${cur}`);
             }
+            if (!!currentProperty.immutable !== !!ancestorProperty.immutable) {
+                const orig = ancestorProperty.immutable ? 'readonly' : 'read-write';
+                const cur = currentProperty.immutable ? 'readonly' : 'read-write';
+                throw new Error(`${currentFqn}.${currentProperty.name}: immutability changed from ${orig} (in ${ancestorFqn}) to ${cur}`);
+            }
             // Register the closest ancestor that is being overridden
             if (!currentProperty.overrides && currentFqn !== ancestorFqn) {
                 currentProperty.overrides = { fqn: ancestorFqn };