refactor: remove a few unnecessary .expect("infallible")

[hanabi1224]

Summary of changes

Changes introduced in this pull request:

Reference issue to close (if applicable)

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Change checklist

• I have performed a self-review of my own code,
• I have made corresponding changes to the documentation. All new code adheres to the team's documentation standards,
• I have added tests that prove my fix is effective or that my feature works (if possible),
• I have made sure the CHANGELOG is up-to-date. All user-facing changes should be reflected in this document.

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Summary by CodeRabbit

• Refactor

  • Streamlined internal construction of non-zero numeric values across authentication, chain sync, and RPC areas to use a simpler, non-fallible approach while preserving behavior.
  • Adjusted cache capacity initialization to the same effective size using the new pattern.

• Tests

  • Simplified test token expiration setup to use non-fallible duration construction.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: 5767c4a7-c17a-4997-9c5f-927694519179

📥 Commits

Reviewing files that changed from the base of the PR and between f4dbce4 and 4abd00f.

📒 Files selected for processing (1)

• src/rpc/methods/f3.rs

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Walkthrough

Replaced fallible NonZero and chrono Duration constructors with non-fallible alternatives: nonzero! macro for NonZero types and direct chrono::Duration constructors in JWT test code. Changes are limited to test and internal initialization sites; no public API changes.

Changes

Cohort / File(s)	Summary
JWT Test Refactoring src/auth/mod.rs	Swapped Duration::try_hours/try_seconds(...).expect("Infallible") for direct chrono::Duration::hours(...) and negated durations in JWT test token-expiration setup.
Index cache capacity src/chain/store/index.rs	Replaced 20480.try_into().expect("infallible") with nonzero!(20480_usize) when initializing SizeTrackingLruCache capacity.
Chain sync NonZero migration src/chain_sync/network_context.rs	Replaced NonZeroU64::new(...).expect("Infallible") with nonzero!(...) at three handle_chain_exchange_request call sites; added nonzero_ext::nonzero import.
RPC (f3) NonZero and cache changes src/rpc/methods/f3.rs	Changed blockstore read-cache capacity to NonZeroUsize via nonzero!(65536_usize), removed prior try_into().expect(...) conversions, and replaced 1.try_into().expect("Infallible") with nonzero!(1_u64); added imports for nonzero_ext::nonzero and std::num::NonZeroUsize.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Suggested labels

RPC

Suggested reviewers

• LesnyRumcajs
• sudo-shashank

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the primary change: refactoring to remove unnecessary .expect("infallible") calls across multiple files, which is what the entire changeset implements.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

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[hanabi1224]

@coderabbitai anything similar in the repo?

[coderabbitai]

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🧩 Analysis chain

🏁 Script executed:

#!/bin/bash
# Search for .expect("infallible") patterns
rg -n 'expect\("infallible"\)' --type rust -C2

echo "---"
# Also search for similar patterns with different casing or wording
rg -n 'expect\("Infallible"\)' --type rust -C2

echo "---"
# Search for unwrap with infallible comments
rg -n 'infallible' --type rust -C2

Repository: ChainSafe/forest
Length of output: 19394

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@hanabi1224 Yes! Here's a summary of similar .expect("infallible") / .expect("Infallible") patterns found across the codebase, grouped by category:

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1. ProgressStyle::with_template with hardcoded strings (same pattern as this PR)

These are trivially infallible since the template strings are compile-time constants:

• src/tool/subcommands/snapshot_cmd.rs:245
• src/tool/subcommands/benchmark_cmd.rs:323
• src/tool/subcommands/car_cmd.rs:109

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2. Hardcoded literal conversions

• src/rpc/methods/f3.rs:534 — 1.try_into().expect("Infallible") (converting the literal 1)
• src/rpc/methods/f3.rs:173 — BLOCKSTORE_CACHE_CAP.try_into().expect("Infallible") (converting a constant)
• src/shim/version.rs:89 — u32::from(other.0).try_into().expect("Infallible")

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3. Fixed-size slice-to-array conversions

• src/db/car/forest.rs:469 — bytes[8..16].try_into().expect("infallible") — the slice length is structurally guaranteed by [u8; Self::SIZE]

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4. Hardcoded valid string parsing

• src/libp2p/config.rs:42,43 — "/ip4/0.0.0.0/tcp/0".parse().expect("Infallible") and /udp/0/quic-v1 variant
• src/blocks/header/test.rs:13,18 — parsing hardcoded CID/hex strings in tests

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5. Non-empty iterator .last() after .first() check

• src/chain_sync/chain_follower.rs:758 — chain.last().expect("Infallible") immediately after chain.first() succeeds

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6. Regex-validated .parse() calls

• src/cli/subcommands/f3_cmd.rs:334,337 — parsing regex capture groups that are guaranteed to be valid integers

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7. signature.bytes() slice ops (may be justified by invariants)

Multiple occurrences in src/eth/homestead_transaction.rs, src/eth/eip_155_transaction.rs, and src/eth/transaction.rs that assume the signature is always a fixed length. These might be better expressed with a length assertion or a typed wrapper, but the "infallible" claim depends on an upstream invariant.

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🧠 Learnings used

Learnt from: hanabi1224
Repo: ChainSafe/forest PR: 5930
File: build.rs:64-77
Timestamp: 2025-08-13T09:43:20.301Z
Learning: hanabi1224 prefers hard compile-time errors in build scripts rather than runtime safeguards or collision detection, believing it's better to fail fast and fix root causes of issues like malformed snapshot names.

---

Learnt from: hanabi1224
Repo: ChainSafe/forest PR: 6057
File: src/cli/subcommands/f3_cmd.rs:0-0
Timestamp: 2025-09-09T10:37:17.947Z
Learning: hanabi1224 prefers having default timeouts (like 10m for --no-progress-timeout) to prevent commands from hanging indefinitely, even when the timeout flag isn't explicitly provided by users. This fail-fast approach is preferred over requiring explicit flag usage.

---

Learnt from: hanabi1224
Repo: ChainSafe/forest PR: 6644
File: src/rpc/methods/eth/tipset_resolver.rs:168-168
Timestamp: 2026-03-05T01:04:43.904Z
Learning: In the Forest codebase (ChainSafe/forest), `ec` in function names like `get_ec_finalized_tipset` and `get_ec_safe_tipset` stands for "expected-consensus", not "election-confirmation". Doc comments and descriptions referring to these functions should use the term "expected-consensus finality".

[codecov]

Codecov Report

❌ Patch coverage is 50.00000% with 5 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (main@94a5591). Learn more about missing BASE report.
⚠️ Report is 1 commits behind head on main.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
src/chain_sync/network_context.rs	0.00%	3 Missing ⚠️
src/rpc/methods/f3.rs	0.00%	2 Missing ⚠️

Additional details and impacted files

Files with missing lines	Coverage Δ
src/auth/mod.rs	100.00% <100.00%> (ø)
src/chain/store/index.rs	87.11% <100.00%> (ø)
src/rpc/methods/f3.rs	2.06% <0.00%> (ø)
src/chain_sync/network_context.rs	30.68% <0.00%> (ø)

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