copying: deep vs shallow copy module (clone() traps, copy constructors, serialization copy, records, defensive copies, collection copies), 17 contract tests

Co-Authored-By: Claude Sonnet 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_017ic4b4X2xx7RrveVQU9R1N
2026-11-12 20:18:06 +05:30
parent 682b7b067c
commit 38fbd513c9
29 changed files with 1201 additions and 0 deletions
@@ -0,0 +1,17 @@
+== 1. Leak through the constructor ==
+  leaky.size() after the caller clears its own list : 0
+
+== 2. Leak through the getter ==
+  leaky2.getNames() = [asha, ravi, intruder]
+
+== 3. The defensive version ==
+  safe.size() after the caller clears its list : 2
+  safe.getNames().add(...) -> UnsupportedOperationException
+
+== 4. unmodifiableList is a VIEW; List.copyOf is a SNAPSHOT ==
+  source   = [a, b, c]
+  view     = [a, b, c]
+  snapshot = [a, b]
+
+== 5. copyOf is shallow: the ELEMENTS are still shared ==
+  frozen.get(0) = x-mutated