Support [elem, ...] non-empty list shorthand in AbstractCode

[andreashasse]

Summary

Spectral.AbstractCode.convert_type/1 did not handle the Elixir shorthand for a non-empty list type, [elem_type, ...] (or bare [...]), even though the longhand nonempty_list(elem_type) worked fine. A type like @type t :: %{tags: [String.t(), ...]} failed to compile with:

** (ArgumentError) Spectral.AbstractCode: unsupported type AST: ...

Fix

Added two clauses to convert_type/1 in lib/spectral/abstract_code.ex, matching before the existing single-element [elem] clause:

• [elem_ast, {:..., _, _}] → sp_nonempty_list(type: convert_type(elem_ast))
• [{:..., _, _}] (bare [...]) → sp_nonempty_list(type: term)

Improper-list shorthands ([elem | tail], [elem, ... | tail]) were considered but not added: Elixir's typespec compiler treats [a | b] as list(a | b) (already handled by the existing [elem] clause) and rejects [a, ... | b] outright at compile time, so there's no AST shape from maybe_improper_list/nonempty_improper_list shorthand to handle here — those types are already only reachable via their named-type form, which already works.

Testing

• New test/support/nonempty_list_module.ex + test/spectral_nonempty_list_test.exs: encode/decode round-trips a non-empty list, empty list is rejected both ways, and the generated JSON Schema has minItems: 1 and matches nonempty_list(elem)'s schema exactly.
• Added [integer(), ...] / [...] types to test/support/all_types_module.ex, covered by the existing compile-time vs. runtime type_info equivalence test.
• make format && make ci passes (217 tests, 0 failures, no Credo or Dialyzer issues).

🤖 Generated with Claude Code

[Copilot]

🟢 Approval recommended

The changes are fully covered by tests and no unresolved issues remain.

Pull request overview

Adds support for Elixir non-empty list shorthand types in Spectral.AbstractCode.

Changes:

• Converts [...] and [elem, ...] to non-empty list types.
• Adds encoding, decoding, schema, and equivalence coverage.

File summaries

File	Description
test/type_info_equivalence_test.exs	Includes shorthand types in equivalence checks.
test/support/nonempty_list_module.ex	Adds shorthand and longhand fixtures.
test/support/all_types_module.ex	Adds shorthand list fixtures.
test/spectral_nonempty_list_test.exs	Tests validation and schema behavior.
lib/spectral/abstract_code.ex	Handles non-empty list shorthand ASTs.

Review details

• Files reviewed: 5/5 changed files
• Comments generated: 0
• Review effort level: Lite

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