[expo-font][iOS] Fix font registration failing when font was in use.

[aleqsio]

Why

Fixes #28948

How

When unregistering a font, we sometimes bump into a failure.

Now, if the failure code indicates that the font will still be available afterwards, we let the registerFont function complete instead of rethrowing this error.

Test Plan

Tested that this works in standalone app.

Checklist

• Documentation is up to date to reflect these changes (eg: https://docs.expo.dev and README.md).
• Conforms with the Documentation Writing Style Guide
• This diff will work correctly for npx expo prebuild & EAS Build (eg: updated a module plugin).

[expo-bot]

The Pull Request introduced fingerprint changes against the base commit: 56a028d

Fingerprint diff

[
  {
    "type": "dir",
    "filePath": "../../packages/expo-font/ios",
    "reasons": [
      "expoAutolinkingIos"
    ],
    "hash": "eeb1766aaef499afccd13cb634d09e754ec7b445"
  }
]

---

Generated by PR labeler 🤖

[anstapol]

hey @aleqsio how long does it usually takes after the PR is merged for this to get into a release?

[aleqsio]

For a CNG flow (not expo-go), usually a week or so :)

[anstapol]

@aleqsio roger that. Thank you for the fix!

[pera14]

when will this update be live in npm?

[hyochan]

Also waiting for this!

[Lurtroxx]

Waiting this as well. Fonts do not work in my app from latest expo upgrade. Any Expo team member able to comment on when this will be released to the live version? What is the last stable version of Expo that we can use.

[Lurtroxx]

@aleqsio What can be done to test the pull request or integrate into the package. I can install the standalone build from the pull request (or current main branch, since the PR is merged, but not published to NPM), but I do not see how to use it with EAS build. Any advice?

[hyochan]

Here is a patch package for expo-font. This works great!

diff --git a/node_modules/expo-font/ios/FontLoaderModule.swift b/node_modules/expo-font/ios/FontLoaderModule.swift
index 0cce788..f03aa4f 100644
--- a/node_modules/expo-font/ios/FontLoaderModule.swift
+++ b/node_modules/expo-font/ios/FontLoaderModule.swift
@@ -12,7 +12,9 @@ public final class FontLoaderModule: Module {
       // If the font was already registered, unregister it first. Otherwise CTFontManagerRegisterGraphicsFont
       // would fail because of a duplicated font name when the app reloads or someone wants to override a font.
       if let familyName = FontFamilyAliasManager.familyName(forAlias: fontFamilyAlias) {
-        try unregisterFont(named: familyName)
+        guard try unregisterFont(named: familyName) else {
+          return
+        }
       }
 
       // Create a font object from the given file
diff --git a/node_modules/expo-font/ios/FontUtils.swift b/node_modules/expo-font/ios/FontUtils.swift
index 48968db..2e179f4 100644
--- a/node_modules/expo-font/ios/FontUtils.swift
+++ b/node_modules/expo-font/ios/FontUtils.swift
@@ -67,19 +67,30 @@ internal func registerFont(_ font: CGFont) throws {
 /**
  Unregisters the given font, so the app will no longer be able to render it.
  */
-internal func unregisterFont(_ font: CGFont) throws {
+internal func unregisterFont(_ font: CGFont) throws -> Bool {
   var error: Unmanaged<CFError>?
 
   if !CTFontManagerUnregisterGraphicsFont(font, &error), let error = error?.takeRetainedValue() {
-    throw FontRegistrationFailedException(error)
+    if let ctFontManagerError = CTFontManagerError(rawValue: CFErrorGetCode(error as CFError)) {
+      switch ctFontManagerError {
+      case .systemRequired, .inUse:
+        return false
+      case .notRegistered:
+        return true
+      default:
+        throw FontRegistrationFailedException(error)
+      }
+    }
   }
+  return true
 }
 
 /**
  Unregisters a font with the given name, so the app will no longer be able to render it.
  */
-internal func unregisterFont(named fontName: String) throws {
+internal func unregisterFont(named fontName: String) throws -> Bool {
   if let font = CGFont(fontName as CFString) {
-    try unregisterFont(font)
+    return try unregisterFont(font)
   }
+  return true
 }
\ No newline at end of file

[Lurtroxx]

@hyochan Unfortunately, this did not work.

[diceros-soojungkim]

also waiting for this!

[pera14]

@aleqsio what's going on with this? Is there any solution for the ongoing issue or it's sorted? If that's the case, can you please tell us how to apply that

[aleqsio]

@pera14 Make sure to update to the latest expo-font package version - it should be fixed there.

[pera14]

@aleqsio I installed the latest expo-font@12.0.6 and expo@51.0.9 and I still have an issue when I build the app, and reopen it, after pressing any button, the app will crash.

[aleqsio]

This sounds like an unrelated issue - this one was happening on an app reload.

You can try to open an issue with a fresh reproduction - I'm pretty sure the issue in the repro linked here was fixed already.

[pera14]

Can you try to open a new issue then since I have had this issue for a long time and I thought it was related to this because it was crashing the app on reload as well

[hyochan]

I've just realized that this patch doesn't work in release mode while it is fine in development.
When I remove the newArch, it works again.

Let me investigate further and come back.

[Lurtroxx]

@hyochan no need to use patch package anymore, new version of Expo fixes this.

[hyochan]

Disabling newArch works fine with this updates. With newArch, it only works in dev client and not production mode (tested in android device).