Use a qualified metadata key for removeTraits

README.md

@@ -136,14 +136,16 @@ After the `addMembers` transformer runs, `MyStruct` has the original `original`
 
 ## `removeTraits`
 
-Unlike the others, this one isn't driven by a trait — it's model-wide, so there's no shape to attach it to. It's configured by the `removeTraits` metadata key, whose type is declared with Smithy's [`@metadata` trait](https://smithy.io/2.0/spec/model.html#metadata-trait), so the value is validated as part of loading the model.
+Unlike the others, this one isn't driven by a trait — it's model-wide, so there's no shape to attach it to. It's configured by the `smithytransformations#removeTraits` metadata key, whose type is declared with Smithy's [`@metadata` trait](https://smithy.io/2.0/spec/model.html#metadata-trait), so the value is validated as part of loading the model.
+
+Metadata keys are plain strings — Smithy attaches no namespace meaning to the `#`. It's qualified here purely to avoid collisions: metadata is merged across every model loaded together, so a bare `removeTraits` would clash with any other library that picked the same word. (The transformer's *name*, used in `smithy4sModelTransformers` and `smithy-build.json`, is just `removeTraits`.)
 
 Each entry is a [selector](https://smithy.io/2.0/spec/selectors.html) matching the **trait definition shapes** to strip:
 
 ```smithy
 $version: "2"
 
-metadata "removeTraits" = [
+metadata "smithytransformations#removeTraits" = [
     "[trait|trait][id|namespace = 'smithy.rules']"  // every trait in the namespace
     "[id = 'smithy.api#deprecated']"                // just this one trait
 ]

smithy4sExample/src/main/smithy/example.smithy

@@ -1,7 +1,7 @@
 $version: "2"
 
 // every trait in the `custom` namespace is stripped from the model before codegen runs
-metadata "removeTraits" = ["[trait|trait][id|namespace = 'custom']"]
+metadata "smithytransformations#removeTraits" = ["[trait|trait][id|namespace = 'custom']"]
 
 namespace example
 

tests/src/test/scala/smithytransformations/RemoveTraitsTest.scala

@@ -32,7 +32,7 @@ class RemoveTraitsTest extends FunSuite {
         customTraits,
         """|$version: "2"
            |
-           |metadata "removeTraits" = ["[trait|trait][id|namespace = 'custom']"]
+           |metadata "smithytransformations#removeTraits" = ["[trait|trait][id|namespace = 'custom']"]
            |
            |namespace example
            |
@@ -52,7 +52,7 @@ class RemoveTraitsTest extends FunSuite {
         customTraits,
         """|$version: "2"
            |
-           |metadata "removeTraits" = ["[trait|trait][id|namespace = 'custom']"]
+           |metadata "smithytransformations#removeTraits" = ["[trait|trait][id|namespace = 'custom']"]
            |
            |namespace example
            |
@@ -71,7 +71,7 @@ class RemoveTraitsTest extends FunSuite {
         customTraits,
         """|$version: "2"
            |
-           |metadata "removeTraits" = ["[id = 'custom#alpha']"]
+           |metadata "smithytransformations#removeTraits" = ["[id = 'custom#alpha']"]
            |
            |namespace example
            |
@@ -89,7 +89,7 @@ class RemoveTraitsTest extends FunSuite {
         customTraits,
         """|$version: "2"
            |
-           |metadata "removeTraits" = ["[id = 'custom#alpha']"]
+           |metadata "smithytransformations#removeTraits" = ["[id = 'custom#alpha']"]
            |
            |namespace example
            |
@@ -111,7 +111,7 @@ class RemoveTraitsTest extends FunSuite {
         otherTraits,
         """|$version: "2"
            |
-           |metadata "removeTraits" = ["[trait|trait][id|namespace = 'custom']", "[id = 'other#gamma']"]
+           |metadata "smithytransformations#removeTraits" = ["[trait|trait][id|namespace = 'custom']", "[id = 'other#gamma']"]
            |
            |namespace example
            |
@@ -133,7 +133,7 @@ class RemoveTraitsTest extends FunSuite {
         otherTraits,
         """|$version: "2"
            |
-           |metadata "removeTraits" = ["[trait|trait][id|namespace = 'custom']", "[id = 'other#gamma']"]
+           |metadata "smithytransformations#removeTraits" = ["[trait|trait][id|namespace = 'custom']", "[id = 'other#gamma']"]
            |
            |namespace example
            |
@@ -164,7 +164,7 @@ class RemoveTraitsTest extends FunSuite {
     val model =
       """|$version: "2"
          |
-         |metadata "removeTraits" = []
+         |metadata "smithytransformations#removeTraits" = []
          |
          |namespace example
          |
@@ -180,7 +180,7 @@ class RemoveTraitsTest extends FunSuite {
     val model =
       """|$version: "2"
          |
-         |metadata "removeTraits" = ["[trait|trait][id|namespace = 'nope']"]
+         |metadata "smithytransformations#removeTraits" = ["[trait|trait][id|namespace = 'nope']"]
          |
          |namespace example
          |
@@ -196,15 +196,15 @@ class RemoveTraitsTest extends FunSuite {
     val errors = validationErrorsFor(
       """|$version: "2"
          |
-         |metadata "removeTraits" = "custom"
+         |metadata "smithytransformations#removeTraits" = "custom"
          |
          |namespace example
          |
          |structure MyStruct {}
          |""".stripMargin
     )
     assert(
-      errors.exists(_.contains("removeTraits")),
+      errors.exists(_.contains("smithytransformations#removeTraits")),
       errors.mkString("\n"),
     )
   }
@@ -213,15 +213,15 @@ class RemoveTraitsTest extends FunSuite {
     val errors = validationErrorsFor(
       """|$version: "2"
          |
-         |metadata "removeTraits" = [""]
+         |metadata "smithytransformations#removeTraits" = [""]
          |
          |namespace example
          |
          |structure MyStruct {}
          |""".stripMargin
     )
     assert(
-      errors.exists(_.contains("removeTraits")),
+      errors.exists(_.contains("smithytransformations#removeTraits")),
       errors.mkString("\n"),
     )
   }
@@ -242,7 +242,7 @@ class RemoveTraitsTest extends FunSuite {
            |""".stripMargin,
         """|$version: "2"
            |
-           |metadata "removeTraits" = ["[trait|trait][trait|smithy.api#unstable]"]
+           |metadata "smithytransformations#removeTraits" = ["[trait|trait][trait|smithy.api#unstable]"]
            |
            |namespace example
            |
@@ -270,7 +270,7 @@ class RemoveTraitsTest extends FunSuite {
            |""".stripMargin,
         """|$version: "2"
            |
-           |metadata "removeTraits" = ["[trait|trait][trait|smithy.api#unstable]"]
+           |metadata "smithytransformations#removeTraits" = ["[trait|trait][trait|smithy.api#unstable]"]
            |
            |namespace example
            |
@@ -289,7 +289,7 @@ class RemoveTraitsTest extends FunSuite {
     val model = loadModel(
       """|$version: "2"
          |
-         |metadata "removeTraits" = ["[[[not a selector"]
+         |metadata "smithytransformations#removeTraits" = ["[[[not a selector"]
          |
          |namespace example
          |

transformation/src/main/java/smithytransformations/RemoveTraits.java

@@ -33,7 +33,7 @@
 /**
  * Strips traits off every shape in the model.
  *
- * <p>Configured by the {@code removeTraits} metadata key, whose shape (and therefore whose
+ * <p>Configured by the {@code smithytransformations#removeTraits} metadata key, whose shape (and therefore whose
  * validation) is declared with {@code @metadata} in {@code smithytransformations.smithy}. Metadata
  * rather than a trait, because the transformation is model-wide and has no shape to attach itself
  * to.
@@ -45,7 +45,7 @@
 public final class RemoveTraits implements ProjectionTransformer {
 
     /** Metadata key holding the selectors. Kept in sync with the {@code @metadata} declaration. */
-    static final String METADATA_KEY = "removeTraits";
+    static final String METADATA_KEY = "smithytransformations#removeTraits";
 
     @Override
     public String getName() {

transformation/src/main/resources/META-INF/smithy/smithytransformations.smithy

@@ -38,7 +38,7 @@ map TraitMap {
 
 /// Selectors matching the trait definition shapes whose traits should be stripped off
 /// every shape in the model, e.g. `[trait|trait][id|namespace = 'smithy.rules']`.
-@metadata(key: "removeTraits")
+@metadata(key: "smithytransformations#removeTraits")
 list RemoveTraits {
     member: RemoveTraitsSelector
 }