paritytech / paritytech/parity-scale-codec
Disallow duplicated enum variant indices
Open
Nobody has claimed this yet.
- Dominant language
- Rust
- Stars
- 287
- Forks
- 103
- Avg merge
- 6d 13h
- Merged PRs (30d)
- 1
Description
Currently it is possible to do this:
#[derive(Encode, Decode)]
enum E {
#[codec(index = 0)]
A,
#[codec(index = 0)]
B,
}
Logically it seems like an error and should not compile at all. Admittedly this is a minor issue.
Contributor guide
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First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by locating the Rust derive implementation for Encode and Decode and its existing tests for #[codec(index = ...)]. Reproduce the duplicate-index example, then inspect how enum variants are validated. Done means duplicate indices are rejected at compile time and the behavior is covered by a regression test.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- rust
- Domain
- backend
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 45/100