From 2ffa417665a89cbff7b7def0a61eaad70c3b50cd Mon Sep 17 00:00:00 2001
From: Kristiyan Kostadinov <crisbeto@abv.bg>
Date: Mon, 29 Jul 2024 10:40:47 +0200
Subject: [PATCH] refactor(migrations): add the ability to remove imports in
 the change tracker (#57179)

Updates the `ChangeTracker` to integrate the changes from #57110.

PR Close #57179
---
 .../core/schematics/utils/change_tracker.ts   | 25 ++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/packages/core/schematics/utils/change_tracker.ts b/packages/core/schematics/utils/change_tracker.ts
index a6081ced32f..390e6e2f021 100644
--- a/packages/core/schematics/utils/change_tracker.ts
+++ b/packages/core/schematics/utils/change_tracker.ts
@@ -140,6 +140,25 @@ export class ChangeTracker {
     });
   }
 
+  /**
+   * Removes an import from a file.
+   * @param sourceFile File from which to remove the import.
+   * @param symbolName Original name of the symbol to be removed. Used even if the import is aliased.
+   * @param moduleName Module from which the symbol is imported.
+   */
+  removeImport(sourceFile: ts.SourceFile, symbolName: string, moduleName: string): void {
+    // It's common for paths to be manipulated with Node's `path` utilties which
+    // can yield a path with back slashes. Normalize them since outputting such
+    // paths will also cause TS to escape the forward slashes.
+    moduleName = normalizePath(moduleName);
+
+    if (!this._changes.has(sourceFile)) {
+      this._changes.set(sourceFile, []);
+    }
+
+    this._importManager.removeImport(sourceFile, symbolName, moduleName);
+  }
+
   /**
    * Gets the changes that should be applied to all the files in the migration.
    * The changes are sorted in the order in which they should be applied.
@@ -201,12 +220,16 @@ export class ChangeTracker {
 
   /** Records the pending import changes from the import manager. */
   private _recordImports(): void {
-    const {newImports, updatedImports} = this._importManager.finalize();
+    const {newImports, updatedImports, deletedImports} = this._importManager.finalize();
 
     for (const [original, replacement] of updatedImports) {
       this.replaceNode(original, replacement);
     }
 
+    for (const node of deletedImports) {
+      this.removeNode(node);
+    }
+
     for (const [sourceFile] of this._changes) {
       const importsToAdd = newImports.get(sourceFile.fileName);