formula: restore using replacement from disable!

[cho-m]

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Previous behavior before #21644

This allows providing a single replacement_formula: on the disable! stanza rather than duplicating it in both disable! and deprecate!

e.g.

deprecate! date: "2026-03-06", because: :unmaintained
disable! date: "2026-03-06", because: :unmaintained, replacement_formula: "foo"

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Also remove some T.must and move some T.let to the simpler (nil) case for readability.

[Copilot]

Pull request overview

Updates Formula deprecation/disable metadata handling so disable! can supply replacement information used for deprecation (restoring behavior from before #21644), while also simplifying some Sorbet annotations for readability.

Changes:

• Populate deprecation fields from disable! when disable! is in the future and deprecate! hasn’t set them.
• Refactor deprecate!/disable! to reduce T.must usage and streamline T.let placement.
• Adjust interaction between deprecate! and disable! when both stanzas are present.

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[Copilot]

Same as in deprecate!: replacement_formula ||= replacement/replacement_cask ||= replacement won’t remap when replacement_formula/replacement_cask is "". Because blanks are treated as absent via .presence in the argument validation (and later when setting @disable_replacement_*), consider using .presence || replacement for the remap to avoid blank replacements being stored/propagated.

Suggested change

	replacement_formula ||= replacement
	replacement_cask ||= replacement
	replacement_formula = replacement_formula.presence || replacement
	replacement_cask = replacement_cask.presence || replacement

[Copilot]

The new disable!→deprecation propagation (@deprecation_* ||= ...) changes behavior when both deprecate! and a future disable! are present (e.g., deprecate has no replacement but disable does). There are existing specs for date ordering, but none cover this replacement propagation; please add an RSpec example asserting deprecation_replacement_formula/cask are populated from disable! when missing from deprecate! (in both stanza orders).

[Copilot]

replacement_formula ||= replacement/replacement_cask ||= replacement doesn't treat blank strings as absent, but earlier validation uses .presence (so a blank value is effectively treated like nil). This can leave replacement_formula as "" and then set @deprecation_replacement_* to an empty string. Consider normalizing with .presence (and doing the legacy replacement remap using .presence || replacement) before using these values, so blanks don’t propagate into deprecation metadata/API output.

[Copilot]

In the deprecated branch, @deprecation_replacement_formula = replacement_formula if replacement_formula will also accept an empty string (truthy) and persist it as the replacement. To match the .presence semantics used elsewhere in this method, consider assigning only replacement_formula.presence/replacement_cask.presence (or normalizing once up-front) so blank values don’t override or block fallback behavior.

Suggested change

	@deprecation_reason = because if because
	@deprecation_replacement_formula = replacement_formula if replacement_formula
	@deprecation_replacement_cask = replacement_cask if replacement_cask
	if (present_because = because.presence)
	@deprecation_reason = present_because
	end
	if (present_replacement_formula = replacement_formula.presence)
	@deprecation_replacement_formula = present_replacement_formula
	end
	if (present_replacement_cask = replacement_cask.presence)
	@deprecation_replacement_cask = present_replacement_cask
	end

[MikeMcQuaid]

Thanks! A comment from me and Copilot ones look worth considering.

Self-merge when happy.

[MikeMcQuaid]

Can you add comments here and anywhere else that this odeprecated/odisabled should stay the same between releases 🙇🏻