add lint rule for missing cancellation token in resolve and provide methods, fyi @alexr00 please remove surpression comment

.eslintrc.json

@@ -976,6 +976,7 @@
                 "vscode-dts-create-func": "warn",
                 "vscode-dts-literal-or-types": "warn",
                 "vscode-dts-interface-naming": "warn",
+                "vscode-dts-cancellation": "warn",
                 "vscode-dts-provider-naming": [
                     "warn",
                     {

build/lib/eslint/vscode-dts-cancellation.js

@@ -0,0 +1,33 @@
+"use strict";
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+const experimental_utils_1 = require("@typescript-eslint/experimental-utils");
+module.exports = new class ApiProviderNaming {
+    constructor() {
+        this.meta = {
+            messages: {
+                noToken: 'Function lacks a cancellation token, preferable as last argument',
+            }
+        };
+    }
+    create(context) {
+        return {
+            ['TSInterfaceDeclaration[id.name=/.+Provider/] TSMethodSignature[key.name=/^(provide|resolve).+/]']: (node) => {
+                let found = false;
+                for (let param of node.params) {
+                    if (param.type === experimental_utils_1.AST_NODE_TYPES.Identifier) {
+                        found = found || param.name === 'token';
+                    }
+                }
+                if (!found) {
+                    context.report({
+                        node,
+                        messageId: 'noToken'
+                    });
+                }
+            }
+        };
+    }
+};

build/lib/eslint/vscode-dts-cancellation.ts

@@ -0,0 +1,38 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import * as eslint from 'eslint';
+import { AST_NODE_TYPES, TSESTree } from '@typescript-eslint/experimental-utils';
+
+export = new class ApiProviderNaming implements eslint.Rule.RuleModule {
+
+	readonly meta: eslint.Rule.RuleMetaData = {
+		messages: {
+			noToken: 'Function lacks a cancellation token, preferable as last argument',
+		}
+	};
+
+	create(context: eslint.Rule.RuleContext): eslint.Rule.RuleListener {
+
+		return {
+			['TSInterfaceDeclaration[id.name=/.+Provider/] TSMethodSignature[key.name=/^(provide|resolve).+/]']: (node: any) => {
+
+				let found = false;
+				for (let param of (<TSESTree.TSMethodSignature>node).params) {
+					if (param.type === AST_NODE_TYPES.Identifier) {
+						found = found || param.name === 'token';
+					}
+				}
+
+				if (!found) {
+					context.report({
+						node,
+						messageId: 'noToken'
+					});
+				}
+			}
+		};
+	}
+};

src/vs/vscode.d.ts

@@ -8886,6 +8886,7 @@ declare module 'vscode' {
 		 * @return The resolved tree item or a thenable that resolves to such. It is OK to return the given
 		 * `item`. When no result is returned, the given `item` will be used.
 		 */
+		// eslint-disable-next-line vscode-dts-cancellation
 		resolveTreeItem?(item: TreeItem, element: T): ProviderResult<TreeItem>;
 	}
 

src/vs/vscode.proposed.d.ts

@@ -1582,6 +1582,7 @@ declare module 'vscode' {
 		// eslint-disable-next-line vscode-dts-provider-naming
 		openNotebook(uri: Uri, openContext: NotebookDocumentOpenContext): NotebookData | Promise<NotebookData>;
 		// eslint-disable-next-line vscode-dts-provider-naming
+		// eslint-disable-next-line vscode-dts-cancellation
 		resolveNotebook(document: NotebookDocument, webview: NotebookCommunication): Promise<void>;
 		// eslint-disable-next-line vscode-dts-provider-naming
 		saveNotebook(document: NotebookDocument, cancellation: CancellationToken): Promise<void>;