Implement SerialiseAsCBOR and Eq for AnyScript era by Jimbo4350 · Pull Request #1122 · IntersectMBO/cardano-api

Jimbo4350 · 2026-03-09T20:28:43Z

Changelog

- description: |
    Add `SerialiseAsCBOR (AnyScript era)` and `Eq (AnyScript era)` instances,
    and generators and property tests for CBOR roundtripping.
  type:
  - feature
  projects:
  - cardano-api

Context

Closes #1088

How to trust this PR

AnyScript CBOR serialisation uses the ledger's tagged AlonzoScript format (tag 0 = native script, tags 1–4 = PlutusV1–V4), so round-tripping is unambiguous.
Eq (AnyScript era) uses eqT to resolve the existential lang in AnyPlutusScript, delegating to the underlying Eq instances.
Property tests cover: CBOR roundtrip via H.tripping, and garbage bytes always returning Left.

Checklist

Commit sequence broadly makes sense and commits have useful messages
New tests are added if needed and existing tests are updated. See Running tests for more details
Self-reviewed the diff

Copilot

Pull request overview

Adds CBOR serialisation and equality support for AnyScript in the experimental API, plus generators and property tests to validate CBOR roundtripping for the Conway-era AnyScript wrapper.

Changes:

Implement Eq (AnyScript era) by resolving the existential Plutus language via eqT.
Implement SerialiseAsCBOR (AnyScript era) using the ledger Script encoding (native vs Plutus tagged form).
Add a Conway AnyScript generator and Hedgehog properties for CBOR roundtrip and failure cases.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
`cardano-api/src/Cardano/Api/Experimental/AnyScript.hs`	Adds `Eq` and `SerialiseAsCBOR` instances for `AnyScript` and the `AsAnyScript` type proxy.
`cardano-api/gen/Test/Gen/Cardano/Api/Experimental.hs`	Adds generators for `SimpleScript` in Conway and `AnyScript` values used by tests.
`cardano-api/test/cardano-api-test/Test/Cardano/Api/Experimental.hs`	Adds a new test group with CBOR roundtrip and “garbage bytes” deserialisation properties for `AnyScript`.

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Copilot · 2026-03-10T13:18:26Z

cardano-api/src/Cardano/Api/Experimental/AnyScript.hs

 import Cardano.Api.Ledger.Internal.Reexport qualified as L
+import Cardano.Api.Serialise.Cbor

-import Cardano.Binary qualified as CBOR
+import Cardano.Ledger.Binary qualified as CBOR
 import Cardano.Ledger.Core qualified as L


The module imports two different modules qualified as L (Cardano.Api.Ledger.Internal.Reexport and Cardano.Ledger.Core), which will not compile due to the duplicate qualifier. Use distinct qualifiers (e.g. Ledger vs LedgerCore) or drop one import if it’s redundant, and update the references accordingly.

Copilot · 2026-03-10T13:18:27Z

cardano-api/test/cardano-api-test/Test/Cardano/Api/Experimental.hs

+prop_roundtrip_cbor_any_script :: Property
+prop_roundtrip_cbor_any_script = H.property $ do
+  script <- H.forAll genAnyScript
+  H.tripping script Exp.serialiseToCBOR (Exp.deserialiseFromCBOR Exp.AsAnyScript)


serialiseToCBOR, deserialiseFromCBOR, and AsAnyScript are not exported from Cardano.Api.Experimental, so Exp.serialiseToCBOR / Exp.deserialiseFromCBOR Exp.AsAnyScript won’t typecheck from this import. Either import Cardano.Api.Serialise.Cbor (for the methods) and Cardano.Api.Experimental.AnyScript (for AsAnyScript), or switch to using Api.serialiseToCBOR / Api.deserialiseFromCBOR with AsAnyScript brought into scope.

Copilot · 2026-03-10T13:18:27Z

cardano-api/test/cardano-api-test/Test/Cardano/Api/Experimental.hs

+prop_deserialise_garbage_bytes_returns_left = H.property $ do
+  garbage <- H.forAll $ Gen.bytes (Range.linear 0 128)
+  case Exp.deserialiseFromCBOR Exp.AsAnyScript garbage of
+    Left _ -> H.success
+    Right _ -> H.annotate "Expected deserialisation failure but got Right" >> H.failure


This property is not guaranteed: arbitrary bytes can occasionally form a valid CBOR encoding of a script, so the test can be flaky (sometimes Right). Consider generating bytes that are guaranteed invalid for this decoder (e.g. take a valid serialiseToCBOR output and append extra trailing bytes, or otherwise ensure the bytes cannot match the tagged AlonzoScript encoding).

Add HasTypeProxy and SerialiseAsCBOR instances for AnyScript era, enabling CBOR serialisation/deserialisation of both simple and plutus scripts using the ledger's native Script era encoding format. Closes #1088

Uses eqT to handle the existential lang in AnyPlutusScript, delegating to the underlying Eq instances on SimpleScript and PlutusScriptInEra. Also adds Typeable lang constraint to the AnyPlutusScript constructor.

Adds genAnyScript and genSimpleScriptInEra generators, along with roundtrip and garbage-input property tests for SerialiseAsCBOR AnyScript.

carbolymer · 2026-03-12T11:24:47Z

cardano-api/src/Cardano/Api/Experimental/AnyScript.hs

+                    CBOR.DecoderErrorCustom
+                      ( mconcat
+                          [ "AnyScript PlutusScript ("
+                          , Text.pack (show (Plutus.plutusLanguage plutus))


Suggested change

, Text.pack (show (Plutus.plutusLanguage plutus))

, Text.show (Plutus.plutusLanguage plutus)

carbolymer · 2026-03-12T11:25:01Z

cardano-api/src/Cardano/Api/Experimental/AnyScript.hs

+                          , ")"
+                          ]
+                      )
+                      (Text.pack . show $ pretty e)


Suggested change

(Text.pack . show $ pretty e)

(Text.show $ pretty e)

carbolymer · 2026-03-12T11:27:34Z

cardano-api/src/Cardano/Api/Experimental/AnyScript.hs

+    script <- decodeScript
+    case L.getNativeScript script of
+      Just ns -> Right $ AnySimpleScript (SimpleScript ns)
+      Nothing ->


@copilot Rewrite deserialiseFromCBOR using asum over a list, utilising Alternative Maybe to short-circuit on the first successful parse.

@Jimbo4350 thoughts on #1130 ?

Copilot · 2026-03-12T11:27:42Z

@carbolymer I've opened a new pull request, #1130, to work on those changes. Once the pull request is ready, I'll request review from you.

carbolymer · 2026-03-12T11:29:34Z

cardano-api/test/cardano-api-test/Test/Cardano/Api/Experimental.hs

+
+-- | Deserialising random garbage bytes should always return 'Left'.
+prop_deserialise_garbage_bytes_returns_left :: Property
+prop_deserialise_garbage_bytes_returns_left = H.property $ do


This negative case test is pointless - it does not give us any guarantees and just adds a maintenance burden.

Jimbo4350 force-pushed the jordan/1088-serialise-as-cbor-any-simple-script branch 3 times, most recently from f2fbb2e to da77b52 Compare March 10, 2026 13:06

Jimbo4350 marked this pull request as ready for review March 10, 2026 13:13

Jimbo4350 requested review from carbolymer, dcoutts, erikd and newhoggy as code owners March 10, 2026 13:13

Copilot AI review requested due to automatic review settings March 10, 2026 13:13

Jimbo4350 requested review from CarlosLopezDeLara, disassembler, kevinhammond and palas as code owners March 10, 2026 13:13

Copilot started reviewing on behalf of Jimbo4350 March 10, 2026 13:14 View session

Copilot AI reviewed Mar 10, 2026

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Jimbo4350 force-pushed the jordan/1088-serialise-as-cbor-any-simple-script branch 3 times, most recently from 51d7d8c to 830c361 Compare March 11, 2026 13:11

Jimbo4350 added 4 commits March 11, 2026 09:36

Implement SerialiseAsCBOR for AnyScript era

ae17441

Add HasTypeProxy and SerialiseAsCBOR instances for AnyScript era, enabling CBOR serialisation/deserialisation of both simple and plutus scripts using the ledger's native Script era encoding format. Closes #1088

Add Eq instance for AnyScript era

395a434

Uses eqT to handle the existential lang in AnyPlutusScript, delegating to the underlying Eq instances on SimpleScript and PlutusScriptInEra. Also adds Typeable lang constraint to the AnyPlutusScript constructor.

Add tests for SerialiseAsCBOR AnyScript and generators

99a7894

Adds genAnyScript and genSimpleScriptInEra generators, along with roundtrip and garbage-input property tests for SerialiseAsCBOR AnyScript.

Export AnyScript from Cardano.Api.Experimental

13deb19

Jimbo4350 force-pushed the jordan/1088-serialise-as-cbor-any-simple-script branch from 830c361 to 13deb19 Compare March 11, 2026 13:37

carbolymer reviewed Mar 12, 2026

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Copilot AI mentioned this pull request Mar 12, 2026

Rewrite deserialiseFromCBOR using asum with Alternative Maybe #1130

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Implement SerialiseAsCBOR and Eq for AnyScript era#1122

Implement SerialiseAsCBOR and Eq for AnyScript era#1122
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jordan/1088-serialise-as-cbor-any-simple-script

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	, Text.pack (show (Plutus.plutusLanguage plutus))
	, Text.show (Plutus.plutusLanguage plutus)

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Jimbo4350 commented Mar 9, 2026 •

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