Patch may be applied multiple times

[OliverJAsh]

Reduced test case: https://github.com/OliverJAsh/patch-package-multple-patches-bug

If you clone this test case and run yarn multiple times, you'll find that the patch which adds StreamApiError applies each time yarn is ran, resulting in corrupt code.

patch-package 6.2.2 (latest at time of writing)

[petrbela]

A similar problem happens on Vercel which caches node_modules after a successful build but runs yarn again after reloading the cache on a subsequent build.

[petrbela]

Btw a quick trick to prevent duplication is to make the patch idempotent, i.e. the original code no longer matches the patch after applying the change.

For example, in my case, I changed from:

diff --git a/node_modules/react-native-web/dist/index.js b/node_modules/react-native-web/dist/index.js
index debd306..ca206ec 100644
--- a/node_modules/react-native-web/dist/index.js
+++ b/node_modules/react-native-web/dist/index.js
@@ -71,3 +71,5 @@ export { default as DeviceEventEmitter } from './exports/DeviceEventEmitter'; //
 
 export { default as useColorScheme } from './exports/useColorScheme';
 export { default as useWindowDimensions } from './exports/useWindowDimensions';
+
+export const ViewPropTypes = { style: null }

to

diff --git a/node_modules/react-native-web/dist/index.js b/node_modules/react-native-web/dist/index.js
index debd306..af22832 100644
--- a/node_modules/react-native-web/dist/index.js
+++ b/node_modules/react-native-web/dist/index.js
@@ -70,4 +70,5 @@ export { default as TVEventHandler } from './exports/TVEventHandler'; // plugins
 export { default as DeviceEventEmitter } from './exports/DeviceEventEmitter'; // hooks
 
 export { default as useColorScheme } from './exports/useColorScheme';
+export const ViewPropTypes = { style: null }
 export { default as useWindowDimensions } from './exports/useWindowDimensions';

Since it's now an insertion instead of an addition, the patch sees the insertion points have changed and doesn't get applied again.

[tplk]

Any ideas for a workaround if I can't make it an insertion instead of an addition?

In my case the file is only 2 lines & I can't figure out a way to insert my bit in the middle.

diff --git a/node_modules/@nrwl/jest/src/schematics/jest-project/files/src/test-setup.ts__tmpl__ b/node_modules/@nrwl/jest/src/schematics/jest-project/files/src/test-setup.ts__tmpl__
index ed2d24f..4808e94 100644
--- a/node_modules/@nrwl/jest/src/schematics/jest-project/files/src/test-setup.ts__tmpl__
+++ b/node_modules/@nrwl/jest/src/schematics/jest-project/files/src/test-setup.ts__tmpl__
@@ -1,2 +1,4 @@
+import 'array-flat-polyfill';
 <% if (setupFile === 'angular') { %>import 'jest-preset-angular';
 <% } else if (setupFile === 'web-components') { %>import 'document-register-element';<% } %>
+import 'jsdom-polyfills';

[petrbela]

You can slightly modify one of the existing lines, e.g. by adding a space, as part of the patch. I think that should do the trick.

[tplk]

Yeah, a comment in the middle did the trick, thanks!

diff --git a/node_modules/@nrwl/jest/src/schematics/jest-project/files/src/test-setup.ts__tmpl__ b/node_modules/@nrwl/jest/src/schematics/jest-project/files/src/test-setup.ts__tmpl__
index ed2d24f..4808e94 100644
--- a/node_modules/@nrwl/jest/src/schematics/jest-project/files/src/test-setup.ts__tmpl__
+++ b/node_modules/@nrwl/jest/src/schematics/jest-project/files/src/test-setup.ts__tmpl__
@@ -1,2 +1,5 @@
+import 'array-flat-polyfill';
 <% if (setupFile === 'angular') { %>import 'jest-preset-angular';
+// matching patch hack
 <% } else if (setupFile === 'web-components') { %>import 'document-register-element';<% } %>
+import 'jsdom-polyfills';