From b6c042d0a35b977fc1ab51827805b73dfceefabb Mon Sep 17 00:00:00 2001
From: Pete Bacon Darwin <pete@bacondarwin.com>
Date: Thu, 7 May 2020 08:29:24 +0100
Subject: [PATCH] fix(compiler-cli): ensure `MockFileSystem` handles
 case-sensitivity (#36968)

Previously this class used the file passed in directly to look up files in the
in-memory mock file-system. But this doesn't match the behaviour of
case-insensitive file-systems. Now the look up is done on the canonical
file paths.

PR Close #36968
---
 .../testing/src/mock_file_system.ts           | 46 +++++++++++--------
 1 file changed, 26 insertions(+), 20 deletions(-)

diff --git a/packages/compiler-cli/src/ngtsc/file_system/testing/src/mock_file_system.ts b/packages/compiler-cli/src/ngtsc/file_system/testing/src/mock_file_system.ts
index 7731f5fea6..8382d456f5 100644
--- a/packages/compiler-cli/src/ngtsc/file_system/testing/src/mock_file_system.ts
+++ b/packages/compiler-cli/src/ngtsc/file_system/testing/src/mock_file_system.ts
@@ -119,7 +119,7 @@ export abstract class MockFileSystem implements FileSystem {
   }
 
   ensureDir(path: AbsoluteFsPath): void {
-    const segments = this.splitPath(path);
+    const segments = this.splitPath(path).map(segment => this.getCanonicalPath(segment));
     let current: Folder = this._fileTree;
 
     // Convert the root folder to a canonical empty string `''` (on Windows it would be `'C:'`).
@@ -212,12 +212,29 @@ export abstract class MockFileSystem implements FileSystem {
   protected abstract splitPath<T extends PathString>(path: T): string[];
 
   dump(): Folder {
-    return cloneFolder(this._fileTree);
+    return this.cloneFolder(this._fileTree);
   }
   init(folder: Folder): void {
-    this._fileTree = cloneFolder(folder);
+    this._fileTree = this.cloneFolder(folder);
   }
 
+  private cloneFolder(folder: Folder): Folder {
+    const clone: Folder = {};
+    for (const path in folder) {
+      const item = folder[path];
+      const canonicalPath = this.getCanonicalPath(path);
+      if (isSymLink(item)) {
+        clone[canonicalPath] = new SymLink(this.getCanonicalPath(item.path));
+      } else if (isFolder(item)) {
+        clone[canonicalPath] = this.cloneFolder(item);
+      } else {
+        clone[canonicalPath] = folder[path];
+      }
+    }
+    return clone;
+  }
+
+
   protected findFromPath(path: AbsoluteFsPath, options?: {followSymLinks: boolean}): FindResult {
     const followSymLinks = !!options && options.followSymLinks;
     const segments = this.splitPath(path);
@@ -229,7 +246,7 @@ export abstract class MockFileSystem implements FileSystem {
     segments[0] = '';
     let current: Entity|null = this._fileTree;
     while (segments.length) {
-      current = current[segments.shift()!];
+      current = current[this.getCanonicalPath(segments.shift()!)];
       if (current === undefined) {
         return {path, entity: null};
       }
@@ -252,10 +269,14 @@ export abstract class MockFileSystem implements FileSystem {
   }
 
   protected splitIntoFolderAndFile(path: AbsoluteFsPath): [AbsoluteFsPath, string] {
-    const segments = this.splitPath(path);
+    const segments = this.splitPath(this.getCanonicalPath(path));
     const file = segments.pop()!;
     return [path.substring(0, path.length - file.length - 1) as AbsoluteFsPath, file];
   }
+
+  protected getCanonicalPath<T extends string>(p: T): T {
+    return this.isCaseSensitive() ? p : p.toLowerCase() as T;
+  }
 }
 export interface FindResult {
   path: AbsoluteFsPath;
@@ -300,18 +321,3 @@ export function isSymLink(item: Entity|null): item is SymLink {
 export function isFolder(item: Entity|null): item is Folder {
   return item !== null && !isFile(item) && !isSymLink(item);
 }
-
-function cloneFolder(folder: Folder): Folder {
-  const clone: Folder = {};
-  for (const path in folder) {
-    const item = folder[path];
-    if (isSymLink(item)) {
-      clone[path] = new SymLink(item.path);
-    } else if (isFolder(item)) {
-      clone[path] = cloneFolder(item);
-    } else {
-      clone[path] = folder[path];
-    }
-  }
-  return clone;
-}