feat(chain): add reusable chain_id query-param parser

[midasbal]

Scope

optimum-common only. Adds ParseChainIDParam(raw string, opts ...IDParamOption) (uint64, error) to pkg/chain, plus an AllowZero() option, covering both semantics described in #141: empty means 0 ("all chains"); a present value must be a non-zero uint64 by default; and AllowZero() accepts a literal "0" as an explicit value.

Adopting this in optimum-measurements (replacing its two duplicated parsers) is left to the maintainers, since that repo is private and out of my reach.

Design notes

• One function plus a functional option (IDParamOption / AllowZero()), matching the pattern already used elsewhere in this repo (pkg/net.CurlOpts, pkg/config.Option, pkg/config.RotatorOption, pkg/telemetry.MetricOption) rather than two near-identical named functions.
• The parser accepts any uint64 and does not validate against the known-chain table (ChainMainnet / ChainHoodi). This matches the issue's stated spec ("present values parse as uint64") rather than chain-ID validation. Happy to add a ValidateAgainstKnownChains() style option if you'd prefer the helper to also reject unknown chain IDs; flagging it since it's the one open question from the issue thread that only a maintainer can settle.
• pkg/chain was already the right home: it's the existing chain-ID helper package, and nothing under pkg/net handles inbound parsing.

Refs #141

Summary by CodeRabbit

• New Features
  • Added parsing for numeric chain ID query parameters.
  • Supports whitespace trimming and empty values.
  • Added an option to explicitly allow zero as a valid chain ID.
  • Invalid formats, disallowed zero values, and values exceeding the supported range now return errors.

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• pkg/chain/chain.go
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📝 Walkthrough

Walkthrough

The chain package adds ParseChainIDParam for trimmed decimal uint64 parsing. Empty input returns zero. Zero is rejected by default and accepted with AllowZero(). Parse errors and overflow return errors with a zero result. Tests cover valid inputs, whitespace, zero handling, malformed values, signed values, decimals, and overflow.

Estimated code review effort: 2 (Simple) | ~10 minutes

Merge Risk: ⚪ Minimal · up to 82812

This PR adds a reusable parser for chain_id query parameters, including explicit zero handling; no actionable merge-blocking risk remains beyond normal checks and review.

Suggested reviewers: abergasov, hpsing, swarna1101

🚥 Pre-merge checks | ✅ 8 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 33.33% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 6 functions across 2 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (8 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title follows the required format: feat(chain): plus a short imperative summary. It is 53 characters, has no trailing punctuation, and accurately describes the parser addition.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Scope Discipline	✅ Passed	PASS. The PR commit changes only pkg/chain/chain.go and pkg/chain/chain_test.go. The source changes implement the stated parser and option, and the tests cover the stated behavior. The functional-…
Behavior Safety	✅ Passed	No explicit behavior-safety failure is introduced. ParseChainIDParam trims input, returns zero for trimmed empty input, uses strconv.ParseUint with a 64-bit limit, rejects zero by default, and app…
Over-Engineering	✅ Passed	No explicit over-engineering condition is introduced. The commit adds no cache or unrelated helper layer. chainIDParamConfig and IDParamOption directly implement the requested AllowZero() behavi…
Security	✅ Passed	No security failure is introduced. The changed parser trims input and uses strconv.ParseUint with base 10 and 64-bit bounds, rejects malformed, signed, overflowing, and zero values by default, and ret…

Full details: Scope Discipline

Explanation

PASS. The PR commit changes only pkg/chain/chain.go and pkg/chain/chain_test.go. The source changes implement the stated parser and option, and the tests cover the stated behavior. The functional-option abstraction is directly related to the API and the PR description explains its design. No dependency files or unrelated production files changed in the PR commit.

Full details: Behavior Safety

Explanation

No explicit behavior-safety failure is introduced. ParseChainIDParam trims input, returns zero for trimmed empty input, uses strconv.ParseUint with a 64-bit limit, rejects zero by default, and applies AllowZero as documented. Focused tests cover whitespace, valid boundaries, invalid syntax, zero handling, and overflow. The JWKS change validates payloads before disk persistence and adds fallback and refresh tests; the dependency updates do not change production behavior.

Full details: Over-Engineering

Explanation

No explicit over-engineering condition is introduced. The commit adds no cache or unrelated helper layer. chainIDParamConfig and IDParamOption directly implement the requested AllowZero() behavior and match existing functional-option patterns in pkg/config and pkg/telemetry. The tests check returned IDs and errors for observable inputs. They do not inspect private fields or implementation details.

Full details: Security

Explanation

No security failure is introduced. The changed parser trims input and uses strconv.ParseUint with base 10 and 64-bit bounds, rejects malformed, signed, overflowing, and zero values by default, and returns quoted errors without logging. The AllowZero behavior is explicit. The diff adds no command execution, credentials, cryptography, secrets, manifests, or log sinks. Acceptance of unknown but syntactically valid chain IDs is documented as intentional, and the new API has no repository call sites that activate a security-sensitive path.

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Actionable comments posted: 1

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Inline comments:
In `@pkg/chain/chain.go`:
- Around line 88-92: Reduce the exported AllowZero and ParseChainIDParam
documentation in pkg/chain/chain.go at lines 88-92 and 99-106 to concise one- or
two-line comments while preserving essential behavior details. Remove the
repeated test-table layout comments in pkg/chain/chain_test.go at lines 86-87
and 128-129; no test logic changes are needed.

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📥 Commits

Reviewing files that changed from the base of the PR and between 4674354 and c4f721a.

📒 Files selected for processing (2)

• pkg/chain/chain.go
• pkg/chain/chain_test.go

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