fix(log-parser): validate configured delimiter

[pbreton]

Summary

Validate the log parser's configured delimiter before processing log files.

The delimiter must contain exactly one byte. Invalid configurations now return a descriptive error instead of panicking or silently using only the first byte.

Fixes #4401.

Root cause

process_log_file_events accessed delim.as_bytes()[0] without validating its length:

• An empty delimiter caused an index-out-of-bounds panic.
• A multi-byte delimiter was silently truncated.
• A non-ASCII delimiter used only the first byte of its UTF-8 encoding.

Changes

• Validate delimiters while loading event definitions.
• Preserve newline as the default when the delimiter is omitted.
• Accept single-byte delimiters.
• Reject empty, multi-byte ASCII, and multi-byte UTF-8 delimiters.
• Reuse the validated conversion when processing log files.
• Add table-driven regression coverage.

Validation

• cargo test -p carbide-log-parser
• cargo clippy -p carbide-log-parser --all-targets -- -D warnings
• cargo fmt --all -- --check
• git diff --check

The regression test was confirmed to fail before the fix and pass afterward.

Note

This is an attempt at fully automated issue resolution using Codex with Sol 5.6 Medium.

[coderabbitai]

Summary by CodeRabbit

• New Features

  • Added configurable log delimiters, defaulting to newline.
  • Supports single-byte delimiters for log processing.
  • Log events are now split consistently using the selected delimiter.

• Bug Fixes

  • Invalid delimiters, including empty, multi-byte ASCII, and multi-byte UTF-8 values, are now rejected with validation errors.
  • Incomplete trailing log content is preserved until a complete delimited event is available.

• Tests

  • Added coverage for omitted, valid, invalid, and custom delimiter configurations.

Walkthrough

The log parser validates delimiters through Configuration::delimiter_byte. It uses the validated delimiter for log boundaries and event-definition loading. Tests cover valid, invalid, and configured-delimiter processing cases.

Changes

Delimiter validation

Layer / File(s)	Summary
Delimiter contract and integration crates/log-parser/src/main.rs	Configuration::delimiter_byte accepts omitted and single-byte delimiters and rejects empty or multi-byte values. Log processing and event-definition loading use the validated delimiter.
Delimiter validation and processing tests crates/log-parser/src/tests.rs	Tests cover delimiter validation and confirm that configured delimiters complete records while leaving unfinished suffixes unread.

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

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely identifies delimiter validation as the primary change.
Description check	✅ Passed	The description directly explains the delimiter validation fix, affected failure modes, implementation, and regression tests.
Linked Issues check	✅ Passed	The changes satisfy issue #4401 by rejecting invalid delimiters, preserving the newline default, and preventing truncation and panics.
Out of Scope Changes check	✅ Passed	The changes are limited to delimiter validation, delimiter handling, and related regression tests.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@crates/log-parser/src/main.rs`:
- Line 297: Update the record-processing path around delimiter_byte to use the
delimiter variable for both record detection and splitting instead of hard-coded
newline bytes, while preserving the existing seek calculation. Add a regression
case covering a non-newline delimiter such as "|" with input that lacks a
trailing newline, verifying the record is processed and its offset advances
correctly.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

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Review profile: CHILL

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📥 Commits

Reviewing files that changed from the base of the PR and between 0021e8c and 444d861.

📒 Files selected for processing (2)

• crates/log-parser/src/main.rs
• crates/log-parser/src/tests.rs

[coderabbitai]

Caution

Some comments are outside the diff and can’t be posted inline due to platform limitations.

⚠️ Outside diff range comments (1)

crates/log-parser/src/tests.rs (1)

943-1015: 🎯 Functional Correctness | 🟡 Minor | ⚡ Quick win

Assert the delimiter value and diagnostic. inspect_delimiter currently discards the parsed Configuration and maps every error to (). Assert that omitted and "|" delimiters produce b'\n' and b'|', respectively, and that invalid delimiters return the delimiter-specific diagnostic.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@crates/log-parser/src/tests.rs` around lines 943 - 1015, Update
inspect_delimiter to retain the parsed Configuration and return or assert its
delimiter value, verifying omitted input becomes b'\n' and "|" becomes b'|'.
Preserve the existing test cases while matching invalid inputs against the
delimiter-specific diagnostic instead of mapping all errors to ().

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Outside diff comments:
In `@crates/log-parser/src/tests.rs`:
- Around line 943-1015: Update inspect_delimiter to retain the parsed
Configuration and return or assert its delimiter value, verifying omitted input
becomes b'\n' and "|" becomes b'|'. Preserve the existing test cases while
matching invalid inputs against the delimiter-specific diagnostic instead of
mapping all errors to ().

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Enterprise

Run ID: 2828b677-4d52-4586-b152-3b7afb5f1c78

📥 Commits

Reviewing files that changed from the base of the PR and between 444d861 and 43d41c0.

📒 Files selected for processing (2)

• crates/log-parser/src/main.rs
• crates/log-parser/src/tests.rs

🚧 Files skipped from review as they are similar to previous changes (1)

• crates/log-parser/src/main.rs