Add config for inline JSON Schema maps

This commit adds the useInlineMaps setting to allow users to configure
JSON Schema conversion to inline converted map shapes instead of creating
references.

docs/source-2.0/guides/model-translations/converting-to-openapi.rst

@@ -804,6 +804,26 @@ mapStrategy (``string``)
             }
         }
 
+.. _generate-openapi-jsonschema-setting-useInlineMaps:
+
+useInlineMaps (``boolean``)
+    Configures Smithy to generate ``map`` shapes inline instead of as
+    references. This is necessary for some code generators to distinguish
+    between ``maps`` and ``structure`` shapes when generating.
+
+    .. code-block:: json
+        :caption: smithy-build.json
+
+        {
+            "version": "1.0",
+            "plugins": {
+                "openapi": {
+                    "service": "example.weather#Weather",
+                    "useInlineMaps": true
+                }
+            }
+        }
+
 .. _generate-openapi-jsonschema-setting-schemaDocumentExtensions:
 
 schemaDocumentExtensions (``Map<String, any>``)

smithy-jsonschema/src/main/java/software/amazon/smithy/jsonschema/DefaultRefStrategy.java

@@ -148,6 +148,17 @@ public boolean isInlined(Shape shape) {
             return true;
         }
 
+        // Maps are not inlined by default, but can be if configured.
+        // Maps are usually not a generated type in programming languages,
+        // but JSON schema represents them as "object" types which code
+        // generators may not distinguish from converted structures.
+        //
+        // Some code generators, however, will treat inline "object" types
+        // as maps and referenced ones as structures.
+        if (shape.isMapShape() && config.getUseInlineMaps()) {
+            return true;
+        }
+
         // Strings with the enum trait are never inlined. This helps to ensure
         // that the name of an enum string can be round-tripped from
         // Smithy -> JSON Schema -> Smithy, helps OpenAPI code generators to

smithy-jsonschema/src/main/java/software/amazon/smithy/jsonschema/JsonSchemaConfig.java

@@ -115,6 +115,7 @@ public String toString() {
     private boolean disableDefaultValues = false;
     private boolean disableIntEnums = false;
     private boolean addReferenceDescriptions = false;
+    private boolean useInlineMaps = false;
 
     public JsonSchemaConfig() {
         nodeMapper.setWhenMissingSetter(NodeMapper.WhenMissing.IGNORE);
@@ -479,4 +480,26 @@ public boolean getAddReferenceDescriptions() {
     public void setAddReferenceDescriptions(boolean addReferenceDescriptions) {
         this.addReferenceDescriptions = addReferenceDescriptions;
     }
+
+    /**
+     * Whether to inline map shapes when creating JSON Schema object types
+     * from them.
+     *
+     * <p>Defaults to {@code false}.</p>
+     *
+     * @return Whether to inline map shapes in the resulting schema
+     */
+    public boolean getUseInlineMaps() {
+        return useInlineMaps;
+    }
+
+    /**
+     * Sets whether to inline map shapes when creating JSON schema object types
+     * from them.
+     *
+     * @param useInlineMaps Whether to inline map shapes in the resulting schema.
+     */
+    public void setUseInlineMaps(boolean useInlineMaps) {
+        this.useInlineMaps = useInlineMaps;
+    }
 }

smithy-jsonschema/src/test/java/software/amazon/smithy/jsonschema/JsonSchemaConverterTest.java

@@ -573,6 +573,32 @@ public void supportsMapPropertyNames() {
         assertThat(schema.getAdditionalProperties().get().getType().get(), equalTo("string"));
     }
 
+    @Test
+    public void supportsInlineMapPropertyNames() {
+        ShapeId shapeId = ShapeId.from("smithy.api#String");
+        StringShape string = StringShape.builder().id(shapeId).build();
+        MapShape map = MapShape.builder().id("a.b#Map").key(shapeId).value(shapeId).build();
+        StructureShape container = StructureShape.builder().id("a.b#Container").addMember("map", map.getId()).build();
+        Model model = Model.builder().addShapes(container, map, string).build();
+        JsonSchemaConfig config = new JsonSchemaConfig();
+        config.setUseInlineMaps(true);
+        SchemaDocument document = JsonSchemaConverter.builder()
+                .config(config)
+                .model(model)
+                .build()
+                .convertShape(container);
+        Schema schema = document.getRootSchema();
+
+        assertThat(schema.getProperties().containsKey("map"), equalTo(true));
+        Schema mapMember = schema.getProperties().get("map");
+        assertThat(mapMember.getRef().isPresent(), equalTo(false));
+        assertThat(mapMember.getType().get(), equalTo("object"));
+        assertTrue(mapMember.getPropertyNames().isPresent());
+        assertThat(mapMember.getPropertyNames().get().getType().get(), equalTo("string"));
+        assertTrue(mapMember.getAdditionalProperties().isPresent());
+        assertThat(mapMember.getAdditionalProperties().get().getType().get(), equalTo("string"));
+    }
+
     @Test
     public void supportsMapPatternProperties() {
         ShapeId shapeId = ShapeId.from("smithy.api#String");
@@ -596,6 +622,35 @@ public void supportsMapPatternProperties() {
         assertThat(schema.getPatternProperties().get(pattern).getType().get(), equalTo("string"));
     }
 
+    @Test
+    public void supportsInlineMapPatternProperties() {
+        ShapeId shapeId = ShapeId.from("smithy.api#String");
+        StringShape string = StringShape.builder().id(shapeId).build();
+        String pattern = "[a-z]{1,16}";
+        StringShape key = StringShape.builder().id("a.b#Key")
+                .addTrait(new PatternTrait(pattern)).build();
+        MapShape map = MapShape.builder().id("a.b#Map").key(key.getId()).value(shapeId).build();
+        StructureShape container = StructureShape.builder().id("a.b#Container").addMember("map", map.getId()).build();
+        Model model = Model.builder().addShapes(container, map, key, string).build();
+        JsonSchemaConfig config = new JsonSchemaConfig();
+        config.setUseInlineMaps(true);
+        config.setMapStrategy(JsonSchemaConfig.MapStrategy.PATTERN_PROPERTIES);
+        SchemaDocument document = JsonSchemaConverter.builder()
+                .config(config)
+                .model(model)
+                .build()
+                .convertShape(container);
+        Schema schema = document.getRootSchema();
+
+        assertThat(schema.getProperties().containsKey("map"), equalTo(true));
+        Schema mapMember = schema.getProperties().get("map");
+        assertThat(mapMember.getRef().isPresent(), equalTo(false));
+        assertThat(mapMember.getType().get(), equalTo("object"));
+        assertThat(mapMember.getPatternProperties().size(), equalTo(1));
+        assertTrue(mapMember.getPatternProperties().containsKey(pattern));
+        assertThat(mapMember.getPatternProperties().get(pattern).getType().get(), equalTo("string"));
+    }
+
     @Test
     public void supportsMapPatternPropertiesWithDefaultPattern() {
         ShapeId shapeId = ShapeId.from("smithy.api#String");