Normalize relative ref paths to avoid duplicating schemas

Currently, if an OpenAPI spec contains multiple relative refs to
the same file, but those refs are located in different files and
use different relative paths to reach the one file, swagger-parser
will create a separate, duplicate schema for each relative path
rather than reusing the same schema across all equivalent paths.

For example, given a spec with the following refs:

- In spec root directory, `$ref: ./components/schemas/Thing.yaml`
- In components/paths subdirectory, `$ref: ../../components/schemas/Thing.yaml`

The parser will produce a `Thing` and a `Thing_1` schema object
instead of reusing `Thing` for the second, equivalent reference.

This updates the ref processor to resolve relative paths before
processing relative refs in order to produce a single `Thing` schema
that is reused for all equivalent references.

Author: ctreatma

modules/swagger-parser-v3/src/main/java/io/swagger/v3/parser/processors/ExternalRefProcessor.java

@@ -29,6 +29,8 @@
 import io.swagger.v3.parser.ResolverCache;
 import io.swagger.v3.parser.models.RefFormat;
 import io.swagger.v3.parser.models.RefType;
+import io.swagger.v3.parser.util.RefUtils;
+
 import org.apache.commons.io.FilenameUtils;
 import org.apache.commons.lang3.StringUtils;
 import org.slf4j.LoggerFactory;
@@ -86,6 +88,18 @@ public String processRefToExternalSchema(String $ref, RefFormat refFormat) {
             return renamedRef;
         }
 
+        RefFormat format = computeRefFormat($ref);
+        if (format.equals(RefFormat.RELATIVE)) {
+            String normalizedRef = Paths.get($ref).normalize().toString();
+            System.out.println("Normalized " + $ref + " to " + normalizedRef);
+            renamedRef = cache.getRenamedRef($ref);
+            if (renamedRef != null) {
+                return renamedRef;
+            } else {
+                $ref = normalizedRef;
+            }
+        }
+
         final Schema schema = cache.loadRef($ref, refFormat, Schema.class);
 
         if(schema == null) {

modules/swagger-parser-v3/src/test/java/io/swagger/v3/parser/test/OpenAPIV3ParserTest.java

@@ -1953,6 +1953,18 @@ public void testRelativePath2() {
         Assert.assertEquals(readResult.getOpenAPI().getPaths().get("/pet/findByTags").getGet().getResponses().get("default").getContent().get("application/json").getSchema().get$ref(), "#/components/schemas/ErrorModel");
     }
 
+    @Test
+    public void testExternalRefsNormalization() throws Exception {
+            ParseOptions options = new ParseOptions();
+            options.setResolve(true);
+            SwaggerParseResult result = new OpenAPIV3Parser()
+                            .readLocation("src/test/resources/oas3.fetched/openapi3.yaml", null, options);
+
+            OpenAPI openAPI = result.getOpenAPI();
+            Schema localModel = openAPI.getComponents().getSchemas().get("Event_2");
+            assertNull(localModel);
+    }
+
     private OpenAPI doRelativeFileTest(String location) {
         OpenAPIV3Parser parser = new OpenAPIV3Parser();
         ParseOptions options = new ParseOptions();
@@ -3286,4 +3298,4 @@ public void testIssue1886() {
                 "map-pojo", "set-pojo", "simple-pojo", "translation-item")
         );
     }
-}
+}

modules/swagger-parser-v3/src/test/resources/oas3.fetched/components/parameters/DeviceSearch.yaml

@@ -0,0 +1,5 @@
+description: Search by hostname, description, short_id, reservation short_id, tags, plan name, plan slug, facility code, facility name, operating system name, operating system slug, IP addresses.
+in: query
+name: search
+schema:
+  type: string

modules/swagger-parser-v3/src/test/resources/oas3.fetched/components/parameters/Exclude.yaml

@@ -0,0 +1,12 @@
+description: |-
+  Nested attributes to exclude. Excluded objects will return only the href
+  attribute. Attribute names can be dotted (up to 3 levels) to exclude deeply
+  nested objects.
+in: query
+name: exclude
+schema:
+  items:
+    type: string
+  type: array
+style: form
+explode: false

modules/swagger-parser-v3/src/test/resources/oas3.fetched/components/parameters/Include.yaml

@@ -0,0 +1,12 @@
+description: |-
+  Nested attributes to include. Included objects will return their full
+  attributes. Attribute names can be dotted (up to 3 levels) to included deeply
+  nested objects.
+in: query
+name: include
+schema:
+  items:
+    type: string
+  type: array
+style: form
+explode: false

modules/swagger-parser-v3/src/test/resources/oas3.fetched/components/parameters/Page.yaml

@@ -0,0 +1,9 @@
+description: Page to return
+in: query
+name: page
+schema:
+  default: 1
+  format: int32
+  maximum: 100000
+  minimum: 1
+  type: integer

modules/swagger-parser-v3/src/test/resources/oas3.fetched/components/parameters/PerPage.yaml

@@ -0,0 +1,9 @@
+description: Items returned per page
+in: query
+name: per_page
+schema:
+  default: 10
+  format: int32
+  maximum: 1000
+  minimum: 1
+  type: integer

modules/swagger-parser-v3/src/test/resources/oas3.fetched/components/parameters/ProjectName.yaml

@@ -0,0 +1,5 @@
+description: Filter results by name.
+in: query
+name: name
+schema:
+  type: string

modules/swagger-parser-v3/src/test/resources/oas3.fetched/components/requestBodies/InterconnectionCreateInput.yaml

@@ -0,0 +1,9 @@
+content:
+  application/json:
+    schema:
+      oneOf:
+      - $ref: '../schemas/DedicatedPortCreateInput.yaml'
+      - $ref: '../schemas/VlanFabricVcCreateInput.yaml'
+      - $ref: '../schemas/VrfFabricVcCreateInput.yaml'
+description: Dedicated port or shared interconnection (also known as Fabric VC) creation request
+required: true

modules/swagger-parser-v3/src/test/resources/oas3.fetched/components/requestBodies/InvitationInput.yaml

@@ -0,0 +1,6 @@
+content:
+  application/json:
+    schema:
+      $ref: '../schemas/InvitationInput.yaml'
+description: Invitation to create
+required: true