New Rule: `no-meta-replaced-by`

[bmish]

Based on the newer format for ESLint rule deprecation info:

• https://eslint.org/docs/latest/extend/rule-deprecation#-deprecatedinfo-type
• https://github.com/eslint/rfcs/tree/main/designs/2024-deprecated-rule-metadata

meta.deprecated should be used in place of meta.replacedBy. meta.deprecated has a more standardized format with many possible fields to fully represent a rule deprecation.

[error-four-o-four]

Hey there,

I'd love to work on this issue but I'd also like to clarify a few questions beforehand.

• The goal of this rule is to enforce the usage of the newer format. Therefore a plugin maintainer shouldn't use a boolean type for meta.deprecated either. I was wondering if this should be included here as well or if this sould be a separate rule? I'd prefer the former and because of that a different name like prefer-deprecated-info (?)
• Should it be a rule of type suggestion or problem? I assume suggestion and maybe switch to problem when eslint has reached v10, right?
• I also assume it should be recommended and have no additional options, right?
• Should I wait for feat: move to ESM only #516 ? If neccessary I could contribute to the fork too

Please bare with me because I haven't written a custom rule yet but this seems like a good opportunity

[bmish]

I think there should be one rule called no-meta-replaced-by limited to discouraging use of the deprecated replacedBy property. This should be of rule type problem and should become a recommended rule.

In terms of the property named deprecated, I don't see a problem with a rule providing this as a boolean like deprecated: true. I wrote the original RFC and intended to continue to support booleans here. In my mind, the DeprecatedInfo object format is only necessary when a rule author has additional information to provide about the deprecation, but there's nothing wrong with using a boolean if no further information is available or necessary.

• I've opened a PR in ESLint to confirm if there's consensus on this position with the ESLint team, and if so, to fix the misleading documentation:
• docs: clarify that boolean is still allowed for rule meta.deprecated eslint/eslint#19866

That said, if you want to write a rule encouraging the use of the object-format of deprecated or any other best practices around this property, that would still be fine, although I believe that requiring the object format should be an optional rule. We could perhaps call it prefer-meta-deprecated-object. This would be of rule type suggestion because it's not required to use the object format.

I would not worry about the ESM conversion for now. That is a breaking change so it may take some time to get in.