Fix semantic functionality not working for macro expansion reference documents due to URL encoding

src/sourcekit-lsp/LanguageClientManager.ts

@@ -30,6 +30,7 @@ import { LSPLogger, LSPOutputChannel } from "./LSPOutputChannel";
 import { SwiftOutputChannel } from "../ui/SwiftOutputChannel";
 import { promptForDiagnostics } from "../commands/captureDiagnostics";
 import { activateGetReferenceDocument } from "./getReferenceDocument";
+import { uriConverters } from "./uriConverters";
 
 interface SourceKitLogMessageParams extends langclient.LogMessageParams {
     logName?: string;
@@ -574,6 +575,7 @@ export class LanguageClientManager {
                     };
                 })(),
             },
+            uriConverters: uriConverters,
             errorHandler,
             // Avoid attempting to reinitialize multiple times. If we fail to initialize
             // we aren't doing anything different the second time and so will fail again.

src/sourcekit-lsp/uriConverters.ts

@@ -0,0 +1,75 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the VS Code Swift open source project
+//
+// Copyright (c) 2024 the VS Code Swift project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of VS Code Swift project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import * as vscode from "vscode";
+
+export const uriConverters = {
+    code2Protocol: (value: vscode.Uri) => {
+        if (value.scheme === "sourcekit-lsp") {
+            // Custom encoding for `sourcekit-lsp://` requests having a `parent` parameter which
+            // can be a `file://` URL or a `sourcekit-lsp://` URL.
+            const scheme = value.scheme;
+            const authority = value.authority;
+            const path = value.path;
+            const fragment = value.fragment;
+
+            let query = value.query;
+
+            const parentParameter = "parent=";
+            const parentParameterIndex = query.indexOf("parent=");
+
+            if (parentParameterIndex === -1) {
+                // No need to do this encoding if there's no parent parameter in the
+                // reference document URL
+
+                // Same as the default implementation
+                return value.toString();
+            }
+
+            // Apply encoding from the start of the value of the `parent` parameter's value
+            // till the end of the url string (`parent` parameter is the last parameter of the
+            // reference document url)
+
+            const startIndex = parentParameterIndex + parentParameter.length;
+
+            const before = query.slice(0, startIndex);
+            const toEncode = query.slice(startIndex);
+
+            // Replace only the percent, equals, ampersand signs
+            // This is inline with how sourcekit-lsp handles the URLs in its test cases.
+            const encoded = toEncode.replace(/%/g, "%25").replace(/=/g, "%3D").replace(/&/g, "%26");
+
+            query = before + encoded;
+
+            let uriString = scheme + "://" + authority + path;
+
+            if (query !== "" && query !== null) {
+                uriString += "?" + query;
+            }
+
+            if (fragment !== "" && fragment !== null) {
+                uriString += "#" + fragment;
+            }
+
+            return uriString;
+        } else {
+            // Same as the default implementation
+            return value.toString();
+        }
+    },
+    protocol2Code: (value: string) => {
+        // Same as the default implementation
+        return vscode.Uri.parse(value);
+    },
+};