feat(EXC): Name Section for Metadata Command (#69)

Add support for keeping the name section in the Wasm module when running
the `metadata` command. Currently that command will always drop the name
section when mutating the custom sections.

src/bin/main.rs

@@ -33,6 +33,8 @@ enum SubCommand {
         /// Visibility of metadata
         #[clap(short, long, value_parser = ["public", "private"], default_value = "private")]
         visibility: String,
+        #[clap(short, long)]
+        keep_name_section: bool,
     },
     /// Limit resource usage
     Resource {
@@ -94,6 +96,9 @@ fn main() -> anyhow::Result<()> {
         SubCommand::Optimize {
             keep_name_section, ..
         } => keep_name_section,
+        SubCommand::Metadata {
+            keep_name_section, ..
+        } => keep_name_section,
         _ => false,
     };
     let mut m = ic_wasm::utils::parse_wasm_file(opts.input, keep_name_section)?;
@@ -155,6 +160,7 @@ fn main() -> anyhow::Result<()> {
             data,
             file,
             visibility,
+            keep_name_section: _,
         } => {
             use ic_wasm::metadata::*;
             if let Some(name) = name {

tests/tests.rs

@@ -1,4 +1,5 @@
 use assert_cmd::Command;
+
 use std::fs;
 use std::path::Path;
 
@@ -34,6 +35,21 @@ fn assert_wasm(expected: &str) {
     }
 }
 
+fn assert_functions_are_named() {
+    let path = Path::new(env!("CARGO_MANIFEST_DIR")).join("tests");
+    let out = path.join("out.wasm");
+
+    let module = walrus::Module::from_file(out).unwrap();
+    let name_count = module.funcs.iter().filter(|f| f.name.is_some()).count();
+    let total = module.funcs.iter().count();
+    // Walrus doesn't give direct access to the name section, but as a proxy
+    // just check that moste functions have names.
+    assert!(
+        name_count > total / 2,
+        "Module has {total} functions but only {name_count} have names."
+    )
+}
+
 #[test]
 fn instrumentation() {
     wasm_input("motoko.wasm", true)
@@ -352,3 +368,23 @@ icp:public whatever
         )
         .success();
 }
+
+#[test]
+fn metadata_keep_name_section() {
+    for file in [
+        "motoko.wasm",
+        "classes.wasm",
+        "motoko-region.wasm",
+        "rust.wasm",
+    ] {
+        wasm_input(file, true)
+            .arg("metadata")
+            .arg("foo")
+            .arg("-d")
+            .arg("hello")
+            .arg("--keep-name-section")
+            .assert()
+            .success();
+        assert_functions_are_named();
+    }
+}