Report warnings in diagnostics when we find a tslint config file but encounte an error during actual linting

src/plugin.ts

@@ -1,4 +1,5 @@
 import * as tslint from 'tslint';
+import * as path from 'path';
 import * as ts_module from 'typescript/lib/tsserverlibrary';
 import { TSLINT_ERROR_CODE, TSLINT_ERROR_SOURCE } from './config';
 import { ConfigFileWatcher } from './configFileWatcher';
@@ -160,10 +161,31 @@ export class TSLintPlugin {
                 return diagnostics;
             }
 
-            const file = this.getProgram().getSourceFile(fileName)!;
-
-            for (const warning of result.warnings) {
-                this.logger.info(`[tslint] ${warning}`);
+            const program = this.getProgram();
+            const file = program.getSourceFile(fileName)!;
+            if (result.warnings) {
+                const defaultTsconfigJsonPath = path.join(program.getCurrentDirectory(), 'tslint.json');
+                if ((result.configFilePath && this.ts.sys.fileExists(result.configFilePath)) || this.ts.sys.fileExists(defaultTsconfigJsonPath)) {
+                    // If we have a config file, the user likely wanted to lint. The fact that linting has a
+                    // warning should be reported to them.
+                    for (const warning of result.warnings) {
+                        diagnostics.unshift({
+                            file,
+                            start: 0,
+                            length: 1,
+                            category: this.ts.DiagnosticCategory.Warning,
+                            code: TSLINT_ERROR_CODE,
+                            messageText: warning,
+                        });
+                    }
+                } else {
+                    // If we have not found a config file, then we don't want to annoy users by generating warnings
+                    // about tslint not being installed or misconfigured. In many cases, the user is opening a
+                    // file/project that was not intended to be linted.
+                    for (const warning of result.warnings) {
+                        this.logger.info(`[tslint] ${warning}`);
+                    }
+                }
             }
 
             const tslintProblems = filterProblemsForFile(fileName, result.lintResult.failures);
@@ -332,7 +354,6 @@ export class TSLintPlugin {
             : `${failure.getFailure()}`;
 
         const category = this.getDiagnosticCategory(failure);
-
         return {
             file,
             start: failure.getStartPosition().getPosition(),

src/runner/index.ts

@@ -113,7 +113,6 @@ export class TsLintRunner {
                 warnings: [
                     getInstallFailureMessage(
                         filePath,
-                        configuration.workspaceFolderPath,
                         configuration.packageManager || 'npm'),
                 ],
             };
@@ -392,7 +391,7 @@ function testForExclusionPattern(filePath: string, pattern: string, cwd: string
     return minimatch(filePath, pattern, { dot: true });
 }
 
-function getInstallFailureMessage(filePath: string, workspaceFolder: string | undefined, packageManager: 'npm' | 'yarn'): string {
+function getInstallFailureMessage(filePath: string, packageManager: 'npm' | 'yarn'): string {
     const localCommands = {
         npm: 'npm install tslint',
         yarn: 'yarn add tslint',
@@ -401,23 +400,12 @@ function getInstallFailureMessage(filePath: string, workspaceFolder: string | un
         npm: 'npm install -g tslint',
         yarn: 'yarn global add tslint',
     };
-    if (workspaceFolder) { // workspace opened on a folder
-        return [
-            '',
-            `Failed to load the TSLint library for the document ${filePath}`,
-            '',
-            `To use TSLint in this workspace please install tslint using \'${localCommands[packageManager]}\' or globally using \'${globalCommands[packageManager]}\'.`,
-            'TSLint has a peer dependency on `typescript`, make sure that `typescript` is installed as well.',
-            'You need to reopen the workspace after installing tslint.',
-        ].join('\n');
-    } else {
-        return [
-            `Failed to load the TSLint library for the document ${filePath}`,
-            `To use TSLint for single file install tslint globally using \'${globalCommands[packageManager]}\'.`,
-            'TSLint has a peer dependency on `typescript`, make sure that `typescript` is installed as well.',
-            'You need to reopen VS Code after installing tslint.',
-        ].join('\n');
-    }
+
+    return [
+        `Failed to load the TSLint library for '${filePath}'`,
+        `To use TSLint, please install tslint using \'${localCommands[packageManager]}\' or globally using \'${globalCommands[packageManager]}\'.`,
+        'Be sure to restart your editor after installing tslint.',
+    ].join('\n');
 }
 
 function isJsDocument(filePath: string) {