Honor the exemption list in language service plugin.

Resolves the issue mentioned in microsoft/vscode#116459.

PiperOrigin-RevId: 358426009
Change-Id: Id80e6e4f46207239fdac316e7af2eab91cad17af

src/build.ts

@@ -31,21 +31,25 @@ export function isInBuildMode(cmdArgs: string[]) {
   return false;
 }
 
-/** Perform security checks on a single project. */
-export function performCheck(program: ts.Program): ts.Diagnostic[] {
+/**
+ * Create a new cheker with all enabled rules registered and the exemption list
+ * configured.
+ */
+export function getConfiguredChecker(program: ts.Program):
+    {checker: Checker, errors: ts.Diagnostic[]} {
   let exemptionList: ExemptionList|undefined = undefined;
 
   const exemptionConfigPath = resolveExemptionConfigPath(
       program.getCompilerOptions()['configFilePath'] as string);
 
-  const diagnostics = [];
+  const errors = [];
 
   if (exemptionConfigPath) {
     const projExemptionConfigOrErr = parseExemptionConfig(exemptionConfigPath);
     if (projExemptionConfigOrErr instanceof ExemptionList) {
       exemptionList = projExemptionConfigOrErr;
     } else {
-      diagnostics.push(...projExemptionConfigOrErr);
+      errors.push(...projExemptionConfigOrErr);
     }
   }
 
@@ -65,17 +69,24 @@ export function performCheck(program: ts.Program): ts.Diagnostic[] {
     rule.register(checker);
   }
 
+  return {checker, errors};
+}
+
+/** Perform security checks on a single project. */
+export function performCheck(program: ts.Program): ts.Diagnostic[] {
+  const {checker, errors} = getConfiguredChecker(program);
+
   // Run all enabled checks and collect errors.
   for (const sf of program.getSourceFiles()) {
     // We don't emit errors for delcarations, so might as well skip checking
     // declaration files all together.
     if (sf.isDeclarationFile) continue;
     const tsecErrors = checker.execute(sf).map(
         failure => failure.toDiagnosticWithStringifiedFixes());
-    diagnostics.push(...tsecErrors);
+    errors.push(...tsecErrors);
   }
 
-  return diagnostics;
+  return errors;
 }
 
 const ALL_TSEC_RULE_NAMES =

src/language_service_plugin.ts

@@ -17,11 +17,11 @@
  * directly in the editor.
  */
 
-import {ENABLED_RULES} from './rule_groups';
-import {Checker} from './third_party/tsetse/checker';
 import {ErrorCode} from './third_party/tsetse/error_code';
 import {DiagnosticWithFixes} from './third_party/tsetse/failure';
 import * as ts from 'typescript/lib/tsserverlibrary';
+
+import {getConfiguredChecker} from './build';
 import {createProxy} from './utils';
 
 function diagnosticToCodeFixActions(d: DiagnosticWithFixes):
@@ -86,13 +86,7 @@ class TsecLanguageServicePlugin {
           );
         }
 
-        const checker = new Checker(program);
-
-        // Register all of the rules for now.
-        for (const rule of ENABLED_RULES) {
-          new rule().register(checker);
-        }
-
+        const {checker} = getConfiguredChecker(program);
         const failures = checker.execute(program.getSourceFile(fileName)!);
 
         this.codeFixActions.set(fileName, new Map());