Linter Rule: Disallow commented-out ERB output tags

Rule: erb-no-commented-out-output-tags

Description

Flag ERB comments that look like a temporarily commented-out output tag, i.e. <%#=, <%# =, <%#==, and <%# ==.

Rationale

Commenting out an ERB output tag by inserting a # (which is what most editors do when you toggle a comment on <%= ... %>) is a convenient way to disable a tag while debugging, but it is easy to forget and commit. This rule surfaces those leftovers so they can either be removed or restored.

The rule intentionally only recognizes the = forms. A comment like <%# hello world %> is prose and is never flagged, and neither is a divider such as <%# === Section === %>.

This rule is reported at info severity and does not fail herb lint unless you raise failLevel.

Examples

✅ Good

<%# This is a regular comment %>

<%# === Section divider === %>

<%= link_to "Home", root_path %>

🚫 Bad

<%#= link_to "Home", root_path %>
`<%#=` looks like a temporarily commented ERB output tag. Remove it, or restore it to `<%=` if it's still needed. (erb-no-commented-out-output-tags)

<%# = link_to "Home", root_path %>
`<%# =` looks like a temporarily commented ERB output tag. Remove it, or restore it to `<%=` if it's still needed. (erb-no-commented-out-output-tags)

<%#== raw_content %>
`<%#==` looks like a temporarily commented ERB output tag. Remove it, or restore it to `<%==` if it's still needed. (erb-no-commented-out-output-tags)

References

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