WIP: try to check fixes against language service

palantir · Sep 25, 2016 · 43f204a · 43f204a
1 parent 1506d8b
commit 43f204a
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Showing 2 changed files with 54 additions and 5 deletions.
diff --git a/src/language/languageServiceHost.ts b/src/language/languageServiceHost.ts
@@ -19,6 +19,35 @@ import * as ts from "typescript";
 
 import {createCompilerOptions} from "./utils";
 
+export interface LanguageServiceEditableHost extends ts.LanguageServiceHost {
+    editFile(fileName: string, newContent: string): void;
+}
+
+export function hostFromProgram(program: ts.Program): LanguageServiceEditableHost {
+    const files: {[name: string]: string} = {};
+    const fileVersions: {[name: string]: number} = {};
+    return {
+            getCompilationSettings: () => program.getCompilerOptions(),
+            getCurrentDirectory: () => program.getCurrentDirectory(),
+            getDefaultLibFileName: () => "lib.d.ts",
+            getScriptFileNames: () => program.getRootFileNames(),
+            getScriptSnapshot: (name: string) => ts.ScriptSnapshot.fromString(
+                files.hasOwnProperty(name) ? files[name] :
+                program.getSourceFile(name).getFullText()
+            ),
+            getScriptVersion: (name: string) => fileVersions.hasOwnProperty(name) ? fileVersions[name] + "" : "1",
+            log: () => { /* */ },
+            editFile(fileName: string, newContent: string) {
+                files[fileName] = newContent;
+                if (fileVersions.hasOwnProperty(fileName)) {
+                    fileVersions[fileName]++;
+                } else {
+                    fileVersions[fileName] = 0;
+                }
+            },
+        };
+}
+
 export function createLanguageServiceHost(fileName: string, source: string): ts.LanguageServiceHost {
     return {
         getCompilationSettings: () => createCompilerOptions(),
@@ -31,7 +60,7 @@ export function createLanguageServiceHost(fileName: string, source: string): ts.
     };
 }
 
-export function createLanguageService(fileName: string, source: string) {
-    const languageServiceHost = createLanguageServiceHost(fileName, source);
+export function createLanguageService(fileName: string, source: string, program?: ts.Program) {
+    const languageServiceHost = program ? hostFromProgram(program) : createLanguageServiceHost(fileName, source);
     return ts.createLanguageService(languageServiceHost);
 }
diff --git a/src/rules/noUnusedVariableRule.ts b/src/rules/noUnusedVariableRule.ts
@@ -81,8 +81,9 @@ export class Rule extends Lint.Rules.TypedRule {
     }
 
     public applyWithProgram(sourceFile: ts.SourceFile, program?: ts.Program): Lint.RuleFailure[] {
-        const languageService = Lint.createLanguageService(sourceFile.fileName, sourceFile.getFullText());
-        return this.applyWithWalker(new NoUnusedVariablesWalker(sourceFile, this.getOptions(), languageService, program));
+        let languageServiceHost = program ? Lint.hostFromProgram(program) :
+          Lint.createLanguageServiceHost(sourceFile.fileName, sourceFile.getFullText());
+        return this.applyWithWalker(new NoUnusedVariablesWalker(sourceFile, this.getOptions(), languageServiceHost, program));
     }
 }
 
@@ -95,10 +96,12 @@ class NoUnusedVariablesWalker extends Lint.RuleWalker {
     private ignorePattern: RegExp;
     private isReactUsed: boolean;
     private reactImport: ts.NamespaceImport;
+    private languageService: ts.LanguageService;
 
     constructor(sourceFile: ts.SourceFile, options: Lint.IOptions,
-                private languageService: ts.LanguageService, private program?: ts.Program) {
+                private languageServiceHost: ts.LanguageServiceHost, private program?: ts.Program) {
         super(sourceFile, options);
+        this.languageService = ts.createLanguageService(languageServiceHost);
         this.skipVariableDeclaration = false;
         this.skipParameterDeclaration = false;
         this.hasSeenJsxElement = false;
@@ -424,6 +427,23 @@ class NoUnusedVariablesWalker extends Lint.RuleWalker {
         if (replacements && replacements.length) {
             fix = new Lint.Fix("no-unused-variable", replacements);
         }
+        // If we have the program, we can verify that the fix doesn't introduce failures
+        if (this.program) {
+            const program = this.languageService.getProgram();
+            const sf = this.getSourceFile();
+            const existingDiags = ts.getPreEmitDiagnostics(program, sf);
+            if (existingDiags.length > 0) {
+                throw new Error("Fix existing diagnostics before running no-unused-variable");
+            }
+            (this.languageServiceHost as any).editFile(sf.fileName, fix.apply(sf.getFullText()));
+            const newProgram = this.languageService.getProgram();
+            const newSf = newProgram.getSourceFile(sf.fileName);
+            const newDiags = ts.getPreEmitDiagnostics(newProgram, newSf);
+            if (newDiags.length > 0) {
+                console.error("rejecting fix because it causes errors");
+                return;
+            }
+        }
         this.addFailure(this.createFailure(position, name.length, Rule.FAILURE_STRING_FACTORY(type, name), fix));
     }