Herb Linting Vs. Formatting: Where's The Line?

Understanding the distinction between linting and formatting is crucial for maintaining code quality and consistency in any project. In the context of Herb, a tool that combines both functionalities, the line between these two can sometimes appear blurred. This article delves into the philosophical question of where Herb draws this line, exploring the nuances and implications for developers.

The Core Question: Linting vs. Formatting in Herb

When adopting herb-lint in a project, it's noticeable that it primarily identifies serious issues like accessibility problems or invalid HTML. This is a significant advantage, ensuring the codebase adheres to crucial standards. However, herb-lint also flags formatting-related issues, such as erb-comment-syntax, erb-no-extra-newline, and html-attribute-double-quotes. This raises the question: Where does herb draw the line between linting and formatting?

Understanding Linting

Linting, at its core, is about identifying potential bugs, errors, and stylistic inconsistencies that can lead to code that is difficult to maintain or prone to runtime issues. Linters analyze code for programmatic and stylistic errors, helping developers catch problems early in the development process. Linters enforce coding standards, suggest improvements, and highlight potential pitfalls that might not be immediately obvious.

Understanding Formatting

Formatting, on the other hand, focuses on the aesthetic presentation of code. It deals with aspects like indentation, spacing, line breaks, and the consistent use of quotes. While formatting doesn't directly impact the functionality of the code, it significantly affects readability and maintainability. Properly formatted code is easier to understand, review, and collaborate on.

Herb's Approach: A Blend of Both

Herb appears to blend linting and formatting concerns, which can be surprising for developers accustomed to tools that strictly separate these functions. While some rules, like ensuring valid HTML, clearly fall under linting, others, such as enforcing double quotes for HTML attributes, seem more formatting-oriented. This overlap prompts a deeper exploration into the rationale behind Herb's design choices.

Specific Examples: Walking the Line

Several Herb rules highlight the nuanced boundary between linting and formatting:

• erb-comment-syntax: This rule ensures consistent comment syntax in ERB files. While primarily a formatting concern, consistent comments enhance code clarity and maintainability, blurring the line slightly.
• erb-no-extra-newline: Preventing extra newlines might seem purely cosmetic, but excessive whitespace can obscure code structure and make it harder to read, thus having a mild impact on maintainability.
• erb-no-extra-whitespace-inside-tags: Similar to extra newlines, excessive whitespace within tags can reduce readability. This rule sits on the fence between formatting and maintainability.
• erb-require-trailing-newline: This rule, ensuring every file ends with a newline, is a common formatting practice that helps prevent certain issues with file concatenation and version control systems. It's a formatting rule with practical implications.
• erb-require-whitespace-inside-tags: Requiring whitespace inside tags, when appropriate, improves readability. This rule enhances the visual structure of the code.
• html-attribute-double-quotes: The consistent use of double quotes for HTML attributes is largely a formatting preference, but it also avoids potential issues with special characters and string interpolation.
• html-attribute-equals-spacing: Proper spacing around the equals sign in HTML attributes enhances readability and reduces the risk of misinterpreting attribute assignments. This rule treads the line between formatting and potential bug prevention.
• html-attribute-values-require-quotes: This rule is crucial for preventing bugs. Omitting quotes around attribute values can lead to parsing errors and unexpected behavior. This is a prime example of a rule with both formatting and linting implications.
• html-no-space-in-tag: Preventing spaces within HTML tags is essential for valid HTML syntax. This rule falls squarely within the realm of linting.

These examples illustrate how Herb's rules sometimes address both formatting and potential bug risks, making the distinction less clear-cut. The inclusion of formatting rules in herb-lint suggests a holistic approach to code quality, where presentation and correctness are intertwined.

The ESLint and Prettier Comparison

The separation of concerns between ESLint and Prettier in the JavaScript world provides a useful comparison. ESLint, since version 8.53.0, focuses solely on linting, deprecating formatting rules and recommending the use of Prettier for code formatting. This division allows each tool to specialize in its respective domain, with ESLint ensuring code correctness and Prettier handling code aesthetics.

Why the Separation?

The rationale behind this separation is that formatting rules can often be automatically applied without requiring human judgment, making them ideal for a dedicated formatting tool. Linting, on the other hand, often requires a deeper understanding of the code and its intended behavior, necessitating more nuanced analysis and human intervention. By separating these concerns, developers can leverage the strengths of each type of tool.

Herb's