fix(36416): empty import path causes server crash (#36751)

Author: a-tarasyuk

Diff for: src/services/textChanges.ts

@@ -1238,9 +1238,10 @@ namespace ts.textChanges {
                 }
 
                 case SyntaxKind.ImportDeclaration:
+                    const isFirstImport = sourceFile.imports.length && node === first(sourceFile.imports).parent || node === find(sourceFile.statements, isImportDeclaration);
                     deleteNode(changes, sourceFile, node,
                         // For first import, leave header comment in place
-                        node === sourceFile.imports[0].parent ? { leadingTriviaOption: LeadingTriviaOption.Exclude } : undefined);
+                        isFirstImport ? { leadingTriviaOption: LeadingTriviaOption.Exclude } : undefined);
                     break;
 
                 case SyntaxKind.BindingElement:

Diff for: tests/cases/fourslash/unusedImportDeclaration_withEmptyPath.ts

@@ -0,0 +1,12 @@
+/// <reference path='fourslash.ts' />
+
+// @Filename: /a.ts
+////// leading trivia
+////import * as foo from ""; // trailing trivia
+
+verify.codeFix({
+    description: "Remove import from ''",
+    newFileContent:
+`// leading trivia
+ // trailing trivia`,
+});

Diff for: tests/cases/fourslash/unusedImportDeclaration_withEmptyPath1.ts

@@ -0,0 +1,22 @@
+/// <reference path='fourslash.ts' />
+
+// @Filename: /a.ts
+////// leading trivia
+////import * as foo from "";
+////import { b } from "./b";
+////import { c } from "./c";
+
+// @Filename: /b.ts
+////export const b = null;
+
+// @Filename: /c.ts
+////export const c = null;
+
+verify.codeFix({
+    index: 0,
+    description: "Remove import from ''",
+    newFileContent:
+`// leading trivia
+import { b } from "./b";
+import { c } from "./c";`,
+});

Diff for: tests/cases/fourslash/unusedImportDeclaration_withEmptyPath2.ts

@@ -0,0 +1,22 @@
+/// <reference path='fourslash.ts' />
+
+// @Filename: /a.ts
+////// leading trivia
+////import { b } from "./b";
+////import * as foo from "";
+////import { c } from "./c";
+
+// @Filename: /b.ts
+////export const b = null;
+
+// @Filename: /c.ts
+////export const c = null;
+
+verify.codeFix({
+    index: 1,
+    description: "Remove import from ''",
+    newFileContent:
+`// leading trivia
+import { b } from "./b";
+import { c } from "./c";`,
+});

Diff for: tests/cases/fourslash/unusedImportDeclaration_withEmptyPath3.ts

@@ -0,0 +1,23 @@
+/// <reference path='fourslash.ts' />
+
+// @Filename: /a.ts
+////// leading trivia
+////import { b } from "./b";
+////import { c } from "./c";
+////import * as foo from "";
+
+// @Filename: /b.ts
+////export const b = null;
+
+// @Filename: /c.ts
+////export const c = null;
+
+verify.codeFix({
+    index: 2,
+    description: "Remove import from ''",
+    newFileContent:
+`// leading trivia
+import { b } from "./b";
+import { c } from "./c";
+`,
+});

Diff for: tests/cases/fourslash/unusedImportDeclaration_withEmptyPath4.ts

@@ -0,0 +1,35 @@
+/// <reference path='fourslash.ts' />
+
+// @Filename: /a.ts
+////// leading trivia
+////import * as a from "";
+////import * as b from "";
+////import * as c from "";
+
+verify.codeFix({
+    index: 0,
+    description: "Remove import from ''",
+    newFileContent:
+`// leading trivia
+import * as b from "";
+import * as c from "";`,
+});
+
+verify.codeFix({
+    index: 1,
+    description: "Remove import from ''",
+    newFileContent:
+`// leading trivia
+import * as a from "";
+import * as c from "";`,
+});
+
+verify.codeFix({
+    index: 2,
+    description: "Remove import from ''",
+    newFileContent:
+`// leading trivia
+import * as a from "";
+import * as b from "";
+`
+});

Diff for: tests/cases/fourslash/unusedImportDeclaration_withEmptyPath5.ts

@@ -0,0 +1,44 @@
+/// <reference path='fourslash.ts' />
+
+// @Filename: /main.ts
+////// leading trivia
+////import { a } from "./a";
+////import { b } from "./b";
+////import { c } from "./c";
+
+// @Filename: /a.ts
+////export const a = null;
+
+// @Filename: /b.ts
+////export const b = null;
+
+// @Filename: /c.ts
+////export const c = null;
+
+verify.codeFix({
+    index: 0,
+    description: "Remove import from './a'",
+    newFileContent:
+`// leading trivia
+import { b } from "./b";
+import { c } from "./c";`,
+});
+
+verify.codeFix({
+    index: 1,
+    description: "Remove import from './b'",
+    newFileContent:
+`// leading trivia
+import { a } from "./a";
+import { c } from "./c";`,
+});
+
+verify.codeFix({
+    index: 2,
+    description: "Remove import from './c'",
+    newFileContent:
+`// leading trivia
+import { a } from "./a";
+import { b } from "./b";
+`,
+});