Handle built-in Stellar Asset Contracts (SACs) in contract.Client.from

[quietbits]

Updates

• Client.from now supports SACs. It fetches the contract instance, and when the executable is StellarAsset it builds the client from the embedded SAC spec; otherwise it loads the Wasm and parses the spec as before. This mirrors what BindingGenerator.fromContractId and stellar-cli already do.
• Extracted Server.getContractInstance(contractId). A new public method that fetches the contract instance ledger entry and returns its xdr.ScContractInstance. Both Client.from and getContractWasmByContractId branch off it, so the historical { code: 404, message } rejection for a missing instance lives in exactly one place. This preserves the pre-existing error shape for consumers that inspect err.code (no behavioral change on failure paths).
• Server.getContractWasmByContractId now throws a clear error for a SAC (which has no Wasm bytecode), pointing callers to Client.from, instead of the cryptic XDR crash. Otherwise unchanged and non-breaking.
• Lazy-load the embedded SAC spec. Client.from loads the ~9.5 KB SAC_SPEC via dynamic import() inside the SAC branch, so bundlers can code-split it out of the common contract/client path; it's only fetched when a SAC is actually built.
• Build: set inlineDynamicImports: true on the UMD dist outputs in rollup.config.mjs so the lazily-imported SAC spec stays in a single bundle (explicit guarantee against Rollup's default behavior; bundles are byte-identical).

Backward compatibility

• Success path unchanged.
• Failure paths preserve the existing { code: 404, message } rejection shape (missing instance / missing Wasm) and the same invalid-contract-id behavior.
• New behavior is limited to (a) SACs now succeeding instead of crashing, and (b) a direct call to getContractWasmByContractId on a SAC now throwing a descriptive error.

Testing

• New test/unit/contract/client_from.test.ts: a Wasm baseline plus a SAC case. The SAC case reproduced the exact issue error before the fix and is green after. Fixtures are built in-memory (pure Buffer ops) so the file runs under both the node and browser unit environments.
• New SAC-guard case in test/unit/server/soroban/get_contract_wasm.test.ts.

[Copilot]

Pull request overview

This PR improves Soroban contract client creation and RPC Wasm fetching behavior by correctly handling built-in Stellar Asset Contracts (SACs), which do not have on-chain Wasm bytecode.

Changes:

• Updated contract.Client.from to detect SAC instances and build clients from the embedded SAC_SPEC instead of attempting to fetch Wasm.
• Updated Server#getContractWasmByContractId to fail fast for SACs with a clear, actionable error message.
• Added/updated unit tests to cover SAC handling for both Client.from and getContractWasmByContractId, plus updated generated reference docs accordingly.

Reviewed changes

Copilot reviewed 6 out of 7 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
src/contract/client.ts	Routes SAC contracts through embedded SAC_SPEC instead of Wasm download logic.
src/rpc/server.ts	Adds SAC guard + clearer error for getContractWasmByContractId.
test/unit/contract/client_from.test.ts	New unit coverage for Client.from (Wasm baseline + SAC case).
test/unit/server/soroban/get_contract_wasm.test.ts	Adds SAC-specific failure-mode test for Wasm fetching by contract ID.
docs/reference/contracts-client.md	Updates generated reference to document SAC behavior in Client.from.
docs/reference/network-rpc.md	Updates generated reference to document SAC limitation in getContractWasmByContractId.
.gitignore	Ignores scratch/ directory.

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[Copilot]

Pull request overview

Copilot reviewed 6 out of 7 changed files in this pull request and generated 2 comments.

[Copilot]

Pull request overview

Copilot reviewed 7 out of 8 changed files in this pull request and generated 1 comment.