[GitHub] [beam] TheNeuralBit commented on a change in pull request #11981: [BEAM-8364] SchemaCoder is not consistent with equals

[GitBox <gi...@apache.org>]

TheNeuralBit commented on a change in pull request #11981:
URL: https://github.com/apache/beam/pull/11981#discussion_r442993899



##########
File path: sdks/java/core/src/main/java/org/apache/beam/sdk/schemas/SchemaCoder.java
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@@ -140,7 +140,14 @@ private void verifyDeterministic(Schema schema)
 
   @Override
   public boolean consistentWithEquals() {
-    return true;
+    // We can't guarantee that the user type T has a good equals method, so we assume the coder is
+    // not consistent with equals (BEAM-8364).
+    return false;
+  }

Review comment:
       My only concern with that is if a user's type doesn't have equals defined they'll just get undefined behavior, and not a useful error message. Could we reasonably detect when a user type doesn't meet that requirement and throw an error (or log a warning and have this function return false)?
   
   I think it's technically possible, my first draft of this PR looked at the typeDescriptor and only returned true when the class had equals defined, but I was concerned it was brittle since we don't know the user-defined equals is actually a good one.




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