Detect components in wasmtime compile more robustly (#5592)

The binary version of component is going to change over time so use a
more robust method than checking for a fixed 8 bytes.

Cargo.lock

@@ -3491,6 +3491,7 @@ dependencies = [
  "tempfile",
  "test-programs",
  "tokio",
+ "wasmparser",
  "wasmtime",
  "wasmtime-cache",
  "wasmtime-cli-flags",

Cargo.toml

@@ -41,6 +41,7 @@ listenfd = "1.0.0"
 wat = { workspace = true }
 serde = "1.0.94"
 serde_json = "1.0.26"
+wasmparser = { workspace = true }
 
 [target.'cfg(unix)'.dependencies]
 rustix = { workspace = true, features = ["mm", "param"] }

src/commands/compile.rs

@@ -90,7 +90,15 @@ impl CompileCommand {
         // bytes with the current component model proposal.
         #[cfg(feature = "component-model")]
         {
-            if input.starts_with(b"\0asm\x0a\0\x01\0") {
+            if let Ok(wasmparser::Chunk::Parsed {
+                payload:
+                    wasmparser::Payload::Version {
+                        encoding: wasmparser::Encoding::Component,
+                        ..
+                    },
+                ..
+            }) = wasmparser::Parser::new(0).parse(&input, true)
+            {
                 fs::write(output, engine.precompile_component(&input)?)?;
                 return Ok(());
             }