From 21e5e1d8d237b889e0be1dffb724aea5e84709b1 Mon Sep 17 00:00:00 2001
From: Manuel Guilherme <m.galmanus@gmail.com>
Date: Fri, 14 Aug 2026 18:52:28 -0300
Subject: [PATCH] Fix panic in `contract info interface` when WASM has env meta
 but no spec

`contractenvmetav0` and `contractspecv0` are independent custom sections,
so a WASM can carry env meta without a spec. The command guarded on
`env_meta_base64` being present but then unwrapped `spec_base64`,
panicking instead of reporting "no interface present".

Extract the WASM branch into `spec_from_wasm` so it is unit-testable,
replace the unwrap with a clean `NoInterfacePresent` error, and add
regression tests that build minimal WASM modules with `wasm-encoder`
(already used by soroban-spec-tools tests).

Fixes #2429
---
 Cargo.lock                                    |  1 +
 cmd/soroban-cli/Cargo.toml                    |  1 +
 .../src/commands/contract/info/interface.rs   | 66 ++++++++++++++++---
 3 files changed, 59 insertions(+), 9 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index a63546cca6..a236ce8349 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -5464,6 +5464,7 @@ dependencies = [
  "ulid",
  "url",
  "walkdir",
+ "wasm-encoder 0.235.0",
  "wasm-gen",
  "wasm-opt",
  "wasmparser 0.116.1",
diff --git a/cmd/soroban-cli/Cargo.toml b/cmd/soroban-cli/Cargo.toml
index 76d6fc0323..c379d71d5e 100644
--- a/cmd/soroban-cli/Cargo.toml
+++ b/cmd/soroban-cli/Cargo.toml
@@ -142,3 +142,4 @@ predicates = { workspace = true }
 walkdir = "2.5.0"
 mockito = "1.5.0"
 serial_test = "3.0.0"
+wasm-encoder = "0.235.0"
diff --git a/cmd/soroban-cli/src/commands/contract/info/interface.rs b/cmd/soroban-cli/src/commands/contract/info/interface.rs
index a2dfa1de38..9658cd7e7a 100644
--- a/cmd/soroban-cli/src/commands/contract/info/interface.rs
+++ b/cmd/soroban-cli/src/commands/contract/info/interface.rs
@@ -51,15 +51,7 @@ impl Cmd {
         let Fetched { contract, .. } = fetch(&self.common, &print).await?;
 
         let (base64, spec) = match contract {
-            shared::Contract::Wasm { wasm_bytes } => {
-                let spec = Spec::new(&wasm_bytes)?;
-
-                if spec.env_meta_base64.is_none() {
-                    return Err(NoInterfacePresent());
-                }
-
-                (spec.spec_base64.unwrap(), spec.spec)
-            }
+            shared::Contract::Wasm { wasm_bytes } => spec_from_wasm(&wasm_bytes)?,
             shared::Contract::StellarAssetContract => {
                 Spec::spec_to_base64(stellar_asset_spec::xdr())?
             }
@@ -85,3 +77,59 @@ impl Cmd {
         Ok(())
     }
 }
+
+fn spec_from_wasm(wasm_bytes: &[u8]) -> Result<(String, Vec<crate::xdr::ScSpecEntry>), Error> {
+    let spec = Spec::new(wasm_bytes)?;
+
+    if spec.env_meta_base64.is_none() {
+        return Err(NoInterfacePresent());
+    }
+
+    // `contractenvmetav0` and `contractspecv0` are independent custom
+    // sections, so the presence of env meta does not imply a spec is present.
+    let Some(base64) = spec.spec_base64 else {
+        return Err(NoInterfacePresent());
+    };
+
+    Ok((base64, spec.spec))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::borrow::Cow;
+
+    /// A minimal WASM module containing only the given custom sections.
+    fn wasm_with_custom_sections(sections: &[(&str, &[u8])]) -> Vec<u8> {
+        let mut module = wasm_encoder::Module::new();
+        for (name, data) in sections {
+            module.section(&wasm_encoder::CustomSection {
+                name: Cow::Borrowed(name),
+                data: Cow::Borrowed(data),
+            });
+        }
+        module.finish()
+    }
+
+    #[test]
+    fn env_meta_without_spec_returns_no_interface_error() {
+        // Regression test for https://github.com/stellar/stellar-cli/issues/2429:
+        // `contractenvmetav0` and `contractspecv0` are independent custom
+        // sections, so a WASM can carry env meta without a spec. This used to
+        // panic on `spec.spec_base64.unwrap()`.
+        let wasm = wasm_with_custom_sections(&[("contractenvmetav0", &[])]);
+
+        let result = spec_from_wasm(&wasm);
+
+        assert!(matches!(result, Err(Error::NoInterfacePresent())));
+    }
+
+    #[test]
+    fn missing_env_meta_returns_no_interface_error() {
+        let wasm = wasm_with_custom_sections(&[]);
+
+        let result = spec_from_wasm(&wasm);
+
+        assert!(matches!(result, Err(Error::NoInterfacePresent())));
+    }
+}