Warn on missing types in contract spec

[leighmcculloch]

What

Add Spec::verify() to soroban-spec-tools that checks every UDT referenced in function signatures, event params, and type definitions is defined within the spec. Integrate the check into contract build to emit warnings after a successful build. Add a hidden contract spec-verify subcommand for standalone verification of a WASM file.

Why

Contracts can compile and deploy with incomplete specs when referenced types are missing — for example, due to spec shaking in the SDK. Downstream tooling such as bindings generators and explorers silently fail when types are unresolvable. Surfacing this at build time gives developers an early, actionable signal.

This will also act as a backup safety to help alert us and developers if changes we make and experiment with wrt spec shaking in #2353 cause specs to disappear that were otherwise needed.

Close #2425

[Copilot]

Pull request overview

Adds contract-spec verification to catch missing user-defined types (UDTs) referenced by function signatures/events/types, and surfaces issues as warnings during stellar contract build, with an additional hidden contract spec-verify command for ad-hoc checks.

Changes:

• Implement Spec::verify() in soroban-spec-tools to detect references to undefined UDTs (with built-in exceptions).
• Integrate spec verification into contract build to emit warnings post-build.
• Add hidden contract spec-verify subcommand to verify a WASM’s spec on demand.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
cmd/soroban-cli/src/commands/contract/spec_verify.rs	New hidden CLI command to run spec verification against a provided WASM.
cmd/soroban-cli/src/commands/contract/mod.rs	Wires the hidden spec-verify subcommand into the contract command tree and error plumbing.
cmd/soroban-cli/src/commands/contract/build.rs	Runs Spec::verify() after a successful build and prints warnings.
cmd/crates/soroban-spec-tools/src/lib.rs	Adds the Spec::verify() implementation, warning type, and unit tests.

Comments suppressed due to low confidence (2)

cmd/soroban-cli/src/commands/contract/build.rs:348

• This verification block re-reads the built WASM from disk even though the build step already has the pre- and post-optimization bytes in memory. Consider verifying against the existing wasm_bytes/optimized_wasm_bytes (or moving verification before print_build_summary), to avoid redundant IO and reduce the chance of silently skipping verification due to an unexpected read failure.

                // Verify spec references after build
                match fs::read(&final_path) {
                    Ok(final_wasm_bytes) => {
                        match soroban_spec_tools::Spec::from_wasm(&final_wasm_bytes) {
                            Ok(spec) => {
                                for w in spec.verify() {
                                    print.warnln(format!("{}: {}", p.name, w));
                                }

cmd/crates/soroban-spec-tools/src/lib.rs:183

• verify() can emit duplicate warnings when the same undefined UDT appears multiple times in a single type (e.g., both key and value of a map, or repeated tuple elements), because it unconditionally pushes a warning for every occurrence returned by collect_udt_names. Consider deduplicating by (context, type_name) before pushing to keep build output actionable and avoid warning spam.

                    &input.type_,
                    defined,
                    warnings,
                );
            }
            for output in f.outputs.iter() {
                check_type(
                    &format!("function '{fn_name}' output"),
                    output,

[mootz12]

Minor comments inline