capacitor-plugin-upgrade-v4-to-v5

Capacitor Plugin Upgrade v4 to v5

Move a plugin library to Capacitor 5. Source of truth: https://capacitorjs.com/docs/updating/plugins/5-0

When to Use

Snapshot shows @capacitor/core 4.x in peer/dev deps and the plugin must work in Capacitor 5 apps.
A Capacitor 5 app fails building this plugin with Namespace not specified or Java 17 errors.
The plugin manually conforms to CAPBridgedPlugin or calls getObject() / getArray().

Do not use:

Upgrading an app -> capacitor-app-upgrade-v4-to-v5.
Plugin already on 5 -> capacitor-plugin-upgrade-v5-to-v6. Multi-hop -> capacitor-plugin-upgrades.

Live Project Snapshot

Plugin and Capacitor package snapshot: !node -e "const fs=require('fs');if(!fs.existsSync('package.json'))process.exit(0);const pkg=JSON.parse(fs.readFileSync('package.json','utf8'));const out=['package.name='+(pkg.name||''),'package.version='+(pkg.version||'')];for(const section of ['peerDependencies','dependencies','devDependencies']){for(const [name,version] of Object.entries(pkg[section]||{})){if(name.startsWith('@capacitor/'))out.push(section+'.'+name+'='+version)}}console.log(out.join('\n'))"

Example and native project paths: !find . -maxdepth 3 \( -path './example-app' -o -path './ios' -o -path './android' \)

References

File	Load when
`references/android.md`	Applying Gradle, manifest, Java or Kotlin changes by hand

Preflight

Tool	Minimum
Node.js	16+
Xcode	14.1+
Java	17 (AGP 8)
AGP / Gradle	8.0.0 / 8.0.2
Android SDK defaults	compileSdk 33, targetSdk 33, minSdk 22
iOS deployment target	13.0 (unchanged)

Procedure

Confirm the plugin is on 4.x from the snapshot and the tree is clean (git status).
From the plugin root run:
```
npx @capacitor/plugin-migration-v4-to-v5@latest
```
It edits package.json, android/build.gradle, the wrapper, gradle.properties, and the manifest. Review git diff.
Finish manually anything not applied (references/android.md):
- @capacitor/cli, core, android, ios dev deps to latest-5; peer @capacitor/core to ^5.0.0.
- SDK defaults 33, AGP 8.0.0, Gradle 8.0.2, namespace in android {} and no package= in the manifest, Java 17, Jetifier removed, Kotlin 1.8.20 with kotlin-stdlib.
iOS code: if the plugin conforms to CAPBridgedPlugin manually (no CAP_PLUGIN macro), move requirements to instance level, rename pluginId to identifier, type pluginMethods as [CAPPluginMethod], and drop getMethod(_:). Macro-based plugins need no change.
Android code: call.getObject(key) and call.getArray(key) can now return null. Add null checks and call.reject(...) with a clear message when required.
Update the example app (if present) to Capacitor 5 via capacitor-app-upgrade-v4-to-v5.
Bump the plugin major version and note "Requires Capacitor 5" in the changelog/README.

Verification

grep -n "\"@capacitor/" package.json                         # 5.x everywhere
grep -n "package=" android/src/main/AndroidManifest.xml      # expect none
grep -n "namespace\|VERSION_17\|gradle:8.0.0" android/build.gradle
grep -rn "kotlin-stdlib-jdk" android/build.gradle            # expect none
grep -rn "getObject(\|getArray(" android/src/main/           # each result null-checked
grep -rn "pluginId\b" ios/                                   # only CAPPlugin usages remain
npm run build
npm run verify        # plugin template script: verify:ios + verify:android + verify:web, if present
cd android && ./gradlew clean build test

Run the example app on both platforms and exercise every method.

Error Handling

Error	Fix
`Namespace not specified`	Add `namespace "<package>"` to `android {}` in the plugin `build.gradle`.
`Android Gradle plugin requires Java 17 to run`	Switch the Gradle JDK to 17.
`NullPointerException` from `getObject`/`getArray`	Add null checks (step 5).
Swift: type does not conform to protocol `CAPBridgedPlugin`	Use instance-level `identifier`, `jsName`, `pluginMethods`, or switch to the macro.
`Duplicate class ... kotlin-stdlib-jdk8`	Replace `kotlin-stdlib-jdk7/jdk8` with `kotlin-stdlib`.