Add comprehensive email validation for blocked users

[akshayutture-augment]

Test 3

---

Replicated from ai-code-review-evaluation/discourse-greptile#3

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[akshayutture-augment]

@greptileai

[greptile-apps]

Greptile Overview

Confidence Score: 2/5

• This PR has a critical architectural issue with database writes during validation
• Score reflects the critical logic issue in BlockedEmail.should_block? which modifies database state during validation. While the feature implementation is well-structured with good test coverage, the side-effect in validation violates Rails conventions and could cause transaction rollback issues or race conditions in concurrent scenarios.
• Pay close attention to app/models/blocked_email.rb - the should_block? method needs refactoring to separate statistics tracking from the blocking check

Important Files Changed

File Analysis

Filename	Score	Overview
app/models/blocked_email.rb	2/5	New model for blocking emails with tracking stats; has critical database write during validation issue
lib/validators/email_validator.rb	4/5	Email validation logic extracted from User model; integrates BlockedEmail checks, missing newline
app/models/user.rb	5/5	Refactored to use new EmailValidator instead of inline validation methods
app/controllers/users_controller.rb	5/5	Enhanced error response to include error hash and values for client-side handling

Sequence Diagram

sequenceDiagram
    participant Client as Browser/Client
    participant Controller as UsersController
    participant User as User Model
    participant Validator as EmailValidator
    participant Blocked as BlockedEmail
    participant DB as Database

    Client->>Controller: POST /users/create (email, username, password)
    Controller->>User: User.new_from_params(params)
    Controller->>User: user.save
    User->>User: validate :email, presence: true, uniqueness: true
    User->>Validator: validates :email, email: true
    Validator->>Validator: Check whitelist/blacklist settings
    alt Email passes whitelist/blacklist
        Validator->>Blocked: BlockedEmail.should_block?(email)
        Blocked->>DB: WHERE email = ?
        alt Email found in blocked_emails
            Blocked->>DB: UPDATE match_count, last_match_at
            Blocked->>DB: save()
            Blocked-->>Validator: true/false (based on action_type)
        else Email not found
            Blocked-->>Validator: false
        end
        alt Email is blocked
            Validator->>User: errors.add(:email, "blocked")
        end
    else Email fails whitelist/blacklist
        Validator->>User: errors.add(:email, "not_allowed")
    end
    User-->>Controller: validation result
    alt Validation failed
        Controller->>Client: JSON {success: false, errors: {...}, values: {...}}
        Client->>Client: rejectedEmails.pushObject(email)
        Client->>Client: Re-validate email field
        Client->>Client: Show error on form
    else Validation passed
        Controller->>Client: JSON {success: true, message: ...}
    end

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[greptile-apps]

_{10 files reviewed, 2 comments}

_{Edit Code Review Agent Settings | Greptile}

[greptile-apps]

logic: Modifying database state during validation is problematic. This method writes to the database (record.save) even during read-only validation checks, which can cause issues with transaction rollbacks and violates Rails conventions where validations should be side-effect free.

Prompt To Fix With AI

This is a comment left during a code review.
Path: app/models/blocked_email.rb
Line: 11:19

Comment:
**logic:** Modifying database state during validation is problematic. This method writes to the database (`record.save`) even during read-only validation checks, which can cause issues with transaction rollbacks and violates Rails conventions where validations should be side-effect free.

How can I resolve this? If you propose a fix, please make it concise.

[greptile-apps]

syntax: Missing newline at end of file

Suggested change

	end
	end

Prompt To Fix With AI

This is a comment left during a code review.
Path: lib/validators/email_validator.rb
Line: 24:24

Comment:
**syntax:** Missing newline at end of file

```suggestion
end
```

How can I resolve this? If you propose a fix, please make it concise.