Require component package names/namespace are lowercase (#1505)

Implement WebAssembly/component-model#338

Author: alexcrichton

crates/wasmparser/src/validator/names.rs

@@ -627,9 +627,9 @@ impl<'a> ComponentNameParser<'a> {
     // pkgpath ::= <namespace>+ <label> <projection>*
     fn pkg_path(&mut self, require_projection: bool) -> Result<()> {
         // There must be at least one package namespace
-        self.take_kebab()?;
+        self.take_lowercase_kebab()?;
         self.expect_str(":")?;
-        self.take_kebab()?;
+        self.take_lowercase_kebab()?;
 
         if self
             .features
@@ -638,7 +638,7 @@ impl<'a> ComponentNameParser<'a> {
             // Take the remaining package namespaces and name
             while self.next.starts_with(':') {
                 self.expect_str(":")?;
-                self.take_kebab()?;
+                self.take_lowercase_kebab()?;
             }
         }
 
@@ -823,6 +823,17 @@ impl<'a> ComponentNameParser<'a> {
             .unwrap_or_else(|| self.expect_kebab())
     }
 
+    fn take_lowercase_kebab(&mut self) -> Result<&'a KebabStr> {
+        let kebab = self.take_kebab()?;
+        if let Some(c) = kebab.chars().find(|c| *c != '-' && !c.is_lowercase()) {
+            bail!(
+                self.offset,
+                "character `{c}` is not lowercase in package name/namespace"
+            );
+        }
+        Ok(kebab)
+    }
+
     fn expect_kebab(&mut self) -> Result<&'a KebabStr> {
         let s = self.take_rest();
         self.kebab(s)

tests/local/component-model/naming.wast

@@ -97,3 +97,19 @@
   )
   "`DOWn` is not in kebab case"
 )
+
+(assert_invalid
+  (component
+    (instance (import "A:b/c"))
+  )
+  "character `A` is not lowercase in package name/namespace"
+)
+(assert_invalid
+  (component
+    (instance (import "a:B/c"))
+  )
+  "character `B` is not lowercase in package name/namespace"
+)
+(component
+  (instance (import "a:b/c"))
+)

tests/snapshots/local/component-model/naming.wast/16.print

@@ -0,0 +1,6 @@
+(component
+  (type (;0;)
+    (instance)
+  )
+  (import "a:b/c" (instance (;0;) (type 0)))
+)