Fix: Immutability of Int is broken by BigInt method (#332)

google / starlark-go

Starlark in Go: the Starlark configuration language, implemented in Go

BSD 3-Clause "New" or "Revised" License

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Fix: Immutability of Int is broken by BigInt method (#332) #333

Closed cloudgerman closed 3 years ago

cloudgerman commented 3 years ago

The interface of Int assumes the value is immutable but a reference to its content is leaked through the BigInt() method, which is mutable. This fix resolves the leak by:

making a copy of the *big.Int in MakeBigInt()
returning a copy of the *big.Int content in BigInt()
creating an internal method bigInt() for internal use that still returns reference to the internal big.Int

Fixes: #332

cloudgerman commented 3 years ago

No problem! comments have now the fixes requested