[jira] [Commented] (THRIFT-4513) thrift generated code is not stable for constants

["James E. King, III (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/THRIFT-4513?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16398912#comment-16398912 ] 

James E. King, III commented on THRIFT-4513:
--------------------------------------------

Root cause of this defect was that the compiler was using pointers as keys in a map to store the values being written out.

This meant the results from different compilers and even runs of the same compiler could produce different results.

Now the map is sorted by key content, not the pointer, thus resolving the issue.

> thrift generated code is not stable for constants
> -------------------------------------------------
>
>                 Key: THRIFT-4513
>                 URL: https://issues.apache.org/jira/browse/THRIFT-4513
>             Project: Thrift
>          Issue Type: Improvement
>          Components: Compiler (General)
>            Reporter: Roman Soroka
>            Assignee: James E. King, III
>            Priority: Major
>             Fix For: 0.12.0
>
>
> In certain cases, output generated with java compiler is unstable, this prevents correct incremental generation, artifact caching, etc. 
> This is especially crucible if the goal is reproducible builds: same results for the same source inputs. 
> Here's example: 
> Let's say we have thrift definition:
> const map<string, Enum1Enum2> CONSTANT_MAP =
> { 'key1' : \\{"enum1" : Enum1.ENUM1_VALUE1, "enum2" : Enum2.ENUM2_VALUE}
> ,
>  'key2' : \{"enum1" : Enum1.ENUM1_VALUE2, "enum2" : Enum2.ENUM2_VALUE},
>  'key3' : \{"enum1" : Enum1.ENUM1_VALUE3, "enum2" : Enum2.ENUM2_VALUE},
>  ....
>  }
> Compiler generates code like:
> public static final java.util.Map<java.lang.String,Enum1Enum2> CONSTANT_MAP = new java.util.HashMap<java.lang.String,Enum1Enum2>();
>  static {
>  Enum1Enum2 tmp199 = new Enum1Enum2();
>  tmp199.setEnum1(com.java.package.Enum1.ENUM1_VALUE2);
>  tmp199.setEnum2(com.java.package.Enum2.ENUM2_VALUE);
> CONSTANT_MAP.put("key2", tmp199);
>  Enum1Enum2 tmp200 = new Enum1Enum2();
>  tmp200.setEnum1(com.java.package.Enum1.ENUM1_VALUE1);
>  tmp200.setEnum2(com.java.package.Enum2.ENUM2_VALUE);
> CONSTANT_MAP.put("key1", tmp200);
>  Enum1Enum2 tmp201 = new Enum1Enum2();
>  tmp201.setEnum1(com.java.package.Enum1.ENUM1_VALUE3);
>  tmp201.setEnum2(com.java.package.Enum2.ENUM2_VALUE);
> CONSTANT_MAP.put("key3", tmp201);
> Possible reorderings:
> 1. Values are added in different order from run to run.
> 2. Set methods in value construction may be called in different order.
> Note: this results in equivalent java maps, so there is no runtime issues. 
> Proposed remedy: 
>  When building construction of Constants from JSON, java code generator should use by-key ordering.
>  



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