Eliminate unreachable default branch in Output accessors for default-only responses#816
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czechboy0 merged 4 commits intoapple:mainfrom Sep 16, 2025
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…ly responses) Fixes apple#810 OpenAPI operations that declare only a default response produced an accessor like: switch self { case .default: return …; default: throw … } Since the enum has a single case, the fallback was statically unreachable and triggered a compiler warning: “Default will never be executed.” This change omits the fallback branch when the Output enum is provably single-case (default-only), eliminating the warning and keeping the accessor exhaustive. Accessor signatures remain throwing for source compatibility. Details - Generator: Gate the fallback default branch in [`TypesFileTranslator.translateResponseOutcomeInTypes()`](Sources/_OpenAPIGeneratorCore/Translator/Responses/translateResponseOutcome.swift:31) behind a single-case check (contains default and exactly one response outcome). Multi-case outputs remain unchanged and still throw on mismatches. - Tests: Update default-only expected snippet to match the new, exhaustive switch without a fallback in [`SnippetBasedReferenceTests.swift`](Tests/OpenAPIGeneratorReferenceTests/SnippetBasedReferenceTests.swift:3412). No new tests added.
czechboy0
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Aug 25, 2025
Sources/_OpenAPIGeneratorCore/Translator/Responses/translateResponseOutcome.swift
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Thanks @czechboy0! 🙏 I've committed the suggested change. |
czechboy0
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Aug 26, 2025
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@alxxndrv apologies about the delay - can you rerun the formatter? The CI still seems red |
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@czechboy0 Got it—thanks for the heads-up! I’ve re-run the formatter; should be good to go now |
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Motivation
OpenAPI operations that declare only a default response caused the generator to emit an accessor switch with an extra fallback branch that is statically unreachable, triggering a Swift compiler warning:
Default will never be executed.The OpenAPI spec explicitly allows default as the only entry in the Responses Object, and tooling validates such specs. This change ensures generated code is clean and warning-free for these valid definitions. Fixes #810.Result
For default-only outputs, the accessor is exhaustive and compiles without unreachable code warnings. Multi-case outputs are unchanged and continue to throw for mismatches. No changes to the public API surface or signatures of generated types
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Links
Fixes #810, OpenAPI spec rule: https://spec.openapis.org/oas/v3.1.1.html#responses-object