fix: regex

Author: parker-snyk

lib/extractor/index.ts

@@ -271,8 +271,9 @@ export function isWhitedOutFile(filename: string) {
  * Remove the .wh. prefix from a whiteout file to get the original filename
  */
 export function removeWhiteoutPrefix(filename: string): string {
-  // Replace .wh. that appears at the start or after the last slash
-  return filename.replace(/^(.*\/)?\.wh\./, "$1");
+  // Replace .wh. that appears at the start or after the last slash,
+  // and ensure no slashes come after .wh.
+  return filename.replace(/^(.*\/)?\.wh\.([^\/]*)$/, "$1$2");
 }
 
 function isBufferType(type: FileContent): type is Buffer {

test/lib/extractor/index.spec.ts

@@ -1,4 +1,4 @@
-import { getContentAsString, isWhitedOutFile } from "../../../lib/extractor";
+import { getContentAsString, isWhitedOutFile, removeWhiteoutPrefix } from "../../../lib/extractor";
 import { ExtractAction, ExtractedLayers } from "../../../lib/extractor/types";
 
 describe("index", () => {
@@ -55,3 +55,44 @@ describe("isWhitedOutFile", () => {
     expect(isWhitedOutFile("/the/.wh./in/path/present")).toBe(false);
   });
 });
+
+describe("removeWhiteoutPrefix", () => {
+  test("should remove .wh. prefix from filenames without slashes", () => {
+    expect(removeWhiteoutPrefix(".wh.hosts")).toBe("hosts");
+    expect(removeWhiteoutPrefix(".wh.data")).toBe("data");
+    expect(removeWhiteoutPrefix(".wh.config")).toBe("config");
+    expect(removeWhiteoutPrefix(".wh.")).toBe("");
+    expect(removeWhiteoutPrefix(".wh.file.txt")).toBe("file.txt");
+  });
+
+  test("should remove .wh. prefix after the last slash in paths", () => {
+    expect(removeWhiteoutPrefix("/etc/.wh.hosts")).toBe("/etc/hosts");
+    expect(removeWhiteoutPrefix("/var/lib/.wh.data")).toBe("/var/lib/data");
+    expect(removeWhiteoutPrefix("/.wh.config")).toBe("/config");
+    expect(removeWhiteoutPrefix("/deeply/nested/path/.wh.present")).toBe("/deeply/nested/path/present");
+    expect(removeWhiteoutPrefix("/path/to/.wh.")).toBe("/path/to/");
+  });
+
+  test("should not modify files that don't have .wh. prefix in the correct position", () => {
+    expect(removeWhiteoutPrefix("normal.file")).toBe("normal.file");
+    expect(removeWhiteoutPrefix("/etc/hosts")).toBe("/etc/hosts");
+    expect(removeWhiteoutPrefix("middle.wh.file")).toBe("middle.wh.file");
+    expect(removeWhiteoutPrefix("/path/middle.wh.file")).toBe("/path/middle.wh.file");
+    expect(removeWhiteoutPrefix(".whfile")).toBe(".whfile");
+    expect(removeWhiteoutPrefix("/path/.whfile")).toBe("/path/.whfile");
+    expect(removeWhiteoutPrefix("/path/has/.wh./in/middle")).toBe("/path/has/.wh./in/middle");
+  });
+
+  test("should handle edge cases", () => {
+    expect(removeWhiteoutPrefix("")).toBe("");
+    expect(removeWhiteoutPrefix("/")).toBe("/");
+    expect(removeWhiteoutPrefix("//")).toBe("//");
+    expect(removeWhiteoutPrefix("/.wh.")).toBe("/");
+    expect(removeWhiteoutPrefix("//.wh.test")).toBe("//test");
+  });
+
+  test("should not remove .wh. that appears in the middle of paths", () => {
+    expect(removeWhiteoutPrefix("/the/.wh./in/path/file")).toBe("/the/.wh./in/path/file");
+    expect(removeWhiteoutPrefix("/path/.wh.dir/.wh.file")).toBe("/path/.wh.dir/file");
+  });
+});