sanitizes model names so they're valid class/interface names fixes #4097

 (#4127)

modules/openapi-generator/src/main/java/org/openapitools/codegen/InlineModelResolver.java

@@ -426,17 +426,22 @@ private void fixStringModel(Schema m) {
      * Generates a unique model name. Non-alphanumeric characters will be replaced
      * with underscores
      *
+     * e.g. io.schema.User_name => io_schema_User_name
+     * 
      * @param title String title field in the schema if present
      * @param key String model name
+     *
+     * @return if provided the sanitized {@code title}, else the sanitized {@code key}
      */
     private String resolveModelName(String title, String key) {
         if (title == null) {
-            // for auto-generated schema name, replace non-alphanumeric characters with underscore
-            // to avoid bugs with schema look up with inline schema created on the fly
-            // e.g. io.schema.User_name => io_schema_User_name
-            return uniqueName(key).replaceAll("[^A-Za-z0-9]", "_");
+            if (key == null) {
+                LOGGER.warn("Found an inline schema without the `title` attribute. Default the model name to InlineObject instead. To have better control of the model naming, define the model separately so that it can be reused throughout the spec.");
+                return uniqueName("InlineObject");
+            }
+            return uniqueName(sanitizeName(key));
         } else {
-            return uniqueName(title);
+            return uniqueName(sanitizeName(title));
         }
     }
 
@@ -452,29 +457,31 @@ private void addGenerated(String name, Schema model) {
         generatedSignature.put(Json.pretty(model), name);
     }
 
-    private String uniqueName(String key) {
-        if (key == null) {
-            key = "InlineObject";
-            LOGGER.warn("Found an inline schema without the `title` attribute. Default the model name to InlineObject instead. To have better control of the model naming, define the model separately so that it can be reused throughout the spec.");
+    /**
+     * Sanitizes the input so that it's valid name for a class or interface
+     *
+     * e.g. 12.schema.User name => _2_schema_User_name
+     */
+    private String sanitizeName(final String name) {
+        return name
+            .replaceAll("^[0-9]", "_") // e.g. 12object => _2object
+            .replaceAll("[^A-Za-z0-9]", "_"); // e.g. io.schema.User name => io_schema_User_name
+    }
+
+    private String uniqueName(final String name) {
+        if (openapi.getComponents().getSchemas() == null) {
+            return name;
         }
+
+        String uniqueName = name;
         int count = 0;
-        boolean done = false;
-        key = key.replaceAll("/", "_"); // e.g. /me/videos => _me_videos
-        key = key.replaceAll("[^a-z_\\.A-Z0-9 ]", ""); // FIXME: a parameter
-        // should not be assigned. Also declare the methods parameters as 'final'.
-        while (!done) {
-            String name = key;
-            if (count > 0) {
-                name = key + "_" + count;
-            }
-            if (openapi.getComponents().getSchemas() == null) {
-                return name;
-            } else if (!openapi.getComponents().getSchemas().containsKey(name)) {
-                return name;
+        while (true) {
+            if (!openapi.getComponents().getSchemas().containsKey(uniqueName)) {
+                return uniqueName;
             }
-            count += 1;
+            uniqueName = name + "_" + ++count;
         }
-        return key;
+        // TODO it would probably be a good idea to check against a list of used uniqueNames to make sure there are no collisions
     }
 
     private void flattenProperties(Map<String, Schema> properties, String path) {

modules/openapi-generator/src/test/java/org/openapitools/codegen/InlineModelResolverTest.java

@@ -100,6 +100,35 @@ public void resolveInlineModelTestWithTitle() {
         assertNotNull(address.getProperties().get("street"));
     }
 
+    @Test
+    public void resolveInlineModelTestWithTitleWithSpaces() {
+        OpenAPI openapi = new OpenAPI();
+        openapi.setComponents(new Components());
+        openapi.getComponents().addSchemas("User", new ObjectSchema()
+                .name("user")
+                .description("a common user")
+                .addProperties("name", new StringSchema())
+                .addProperties("address", new ObjectSchema()
+                        .title("User Address Title")
+                        .readOnly(false)
+                        .description("description")
+                        .name("name")
+                        .addProperties("street", new StringSchema())
+                        .addProperties("city", new StringSchema())));
+
+        new InlineModelResolver().flatten(openapi);
+
+        Schema user = openapi.getComponents().getSchemas().get("User");
+
+        assertNotNull(user);
+        assertTrue(user.getProperties().get("address") instanceof Schema);
+
+        Schema address = openapi.getComponents().getSchemas().get("User_Address_Title");
+        assertNotNull(address);
+        assertNotNull(address.getProperties().get("city"));
+        assertNotNull(address.getProperties().get("street"));
+    }
+
     @Test
     public void resolveInlineModel2EqualInnerModels() {
         OpenAPI openapi = new OpenAPI();