Details
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Improvement
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Status: Closed
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Major
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Resolution: Fixed
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None
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None
Description
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' :
,
'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.
