Reject malformed lines instead of silently skipping in internal/config/dotenv.go

[Jagadeeshftw]

📌 Description

internal/config/dotenv.go (51 lines) parses .env files for local/dev config loading. If it currently skips malformed lines (e.g. missing =, stray quotes) without any warning, a typo in an env var silently results in that variable being unset rather than failing fast — which then surfaces as a confusing downstream error in internal/config/config.go.

🧩 Requirements and context

• Inspect current parsing behavior for malformed lines and decide fail-fast vs warn-and-skip (recommend: warn loudly via stderr/logger, since this only affects local dev).
• Add a test for common malformation cases: missing =, unterminated quote, duplicate key, comment-only line, empty file.
• Ensure the existing valid-parsing behavior is unchanged.

Non-functional requirements

• Must be secure, tested, and documented.
• Should be efficient and easy to review.

🛠️ Suggested execution

1. Fork the repo and create a branch

git checkout -b fix/dotenv-malformed-line-warning

2. Implement changes

• Modify: internal/config/dotenv.go — add malformed-line detection and a clear warning log.
• Add test: internal/config/config_test.go (or a new dotenv_test.go) covering the malformation cases.

3. Test and commit

• Run tests:

go test ./internal/config/... -v

• Cover edge cases: missing equals sign, unterminated quote, duplicate key (last-wins vs first-wins), Windows line endings (CRLF).
• Include test output and details in the PR description.

Example commit message

fix: warn on malformed .env lines instead of silently skipping them

✅ Acceptance criteria

• Malformed lines produce a visible warning instead of silent omission.
• Valid .env files parse identically to before.
• Duplicate-key behavior is explicit and tested.

🔒 Security notes

Low direct security impact (dev-only tooling), but a silently-dropped JWT_SECRET or similar could lead to a weak/default value being used unnoticed — validate no sensitive default is used as a fallback.

📋 Guidelines

• Minimum 95% test coverage
• Clear documentation
• Timeframe: 96 hours

[spartan124]

Hi maintainer, I would love to work on this. I have implemeted similar solutions on several projects and I can do same here cleanly and efficiently. Allow me the opportunity to contribute to your project while following contribution guidelines for your project. Kindly assign.

[grantfox-oss]

🦊 GrantFox — @spartan124 has been assigned to this issue as part of the Official Campaign | FWC26 campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #172)
2. Your PR will be reviewed by the Grainlify maintainers

Good luck! Track your progress on GrantFox.

[Jagadeeshftw]

Assigned! Go ahead and open a PR referencing this issue (Closes #172) whenever you're ready. If you have questions along the way, feel free to ask here or join the community: t.me/+vTbe0hOUKrFhNTJl