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Flutter – Duplicate Kotlin classes after installing mobilescanner

First ever Flutter / Android app, apologies in advance.

As soon as I install this qr code scanner it breaks my project (even if I don’t actually import it).

First it complains about the compileSdkVersion and minSdkVersion. After hard coding those to 34 and 21 respectively as suggested by the error, I get a long error about duplicate Kotlin classes when I attempt to build.

The confusing thing is it worked 2 days ago, but somehow I have broken that project and any new project suffers from this problem. Perhaps the most recent update to the library could have caused this?

I’ve tried flutter pub upgrade --major-versions and ./gradlew clean, no effect. I’ve updated Flutter to latest version. I have created empty projects with flutter create <name> and done nothing but attempt to import this lib.

I understand that I must have conflicting kotlin dependencies, and presumably that means the QR scanner library has a dependency that is conflicting with my project? However I am having difficulty resolving that issue.

I am working in VSCode if that is relevant at all. Here is the full error:

Launching lib/main.dart on sdk gphone64 arm64 in debug mode...

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:checkDebugDuplicateClasses'.
> A failure occurred while executing com.android.build.gradle.internal.tasks.CheckDuplicatesRunnable
   > Duplicate class kotlin.collections.jdk8.CollectionsJDK8Kt found in modules jetified-kotlin-stdlib-1.8.22 (org.jetbrains.kotlin:kotlin-stdlib:1.8.22) and jetified-kotlin-stdlib-jdk8-1.7.10 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.7.10)
     Duplicate class kotlin.internal.jdk7.JDK7PlatformImplementations found in modules jetified-kotlin-stdlib-1.8.22 (org.jetbrains.kotlin:kotlin-stdlib:1.8.22) and jetified-kotlin-stdlib-jdk7-1.7.22 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.22)
     Duplicate class kotlin.internal.jdk7.JDK7PlatformImplementations$ReflectSdkVersion found in modules jetified-kotlin-stdlib-1.8.22 (org.jetbrains.kotlin:kotlin-stdlib:1.8.22) and jetified-kotlin-stdlib-jdk7-1.7.22 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.22)
     Duplicate class kotlin.internal.jdk8.JDK8PlatformImplementations found in modules jetified-kotlin-stdlib-1.8.22 (org.jetbrains.kotlin:kotlin-stdlib:1.8.22) and jetified-kotlin-stdlib-jdk8-1.7.10 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.7.10)
     Duplicate class kotlin.internal.jdk8.JDK8PlatformImplementations$ReflectSdkVersion found in modules jetified-kotlin-stdlib-1.8.22 (org.jetbrains.kotlin:kotlin-stdlib:1.8.22) and jetified-kotlin-stdlib-jdk8-1.7.10 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.7.10)
     Duplicate class kotlin.io.path.DirectoryEntriesReader found in modules jetified-kotlin-stdlib-1.8.22 (org.jetbrains.kotlin:kotlin-stdlib:1.8.22) and jetified-kotlin-stdlib-jdk7-1.7.22 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.22)
     Duplicate class kotlin.io.path.ExperimentalPathApi found in modules jetified-kotlin-stdlib-1.8.22 (org.jetbrains.kotlin:kotlin-stdlib:1.8.22) and jetified-kotlin-stdlib-jdk7-1.7.22 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.22)
     Duplicate class kotlin.io.path.FileVisitorBuilder found in modules jetified-kotlin-stdlib-1.8.22 (org.jetbrains.kotlin:kotlin-stdlib:1.8.22) and jetified-kotlin-stdlib-jdk7-1.7.22 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.22)
     Duplicate class kotlin.io.path.FileVisitorBuilderImpl found in modules jetified-kotlin-stdlib-1.8.22 (org.jetbrains.kotlin:kotlin-stdlib:1.8.22) and jetified-kotlin-stdlib-jdk7-1.7.22 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.22)
     Duplicate class kotlin.io.path.FileVisitorImpl found in modules jetified-kotlin-stdlib-1.8.22 (org.jetbrains.kotlin:kotlin-stdlib:1.8.22) and jetified-kotlin-stdlib-jdk7-1.7.22 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.22)
     Duplicate class kotlin.io.path.LinkFollowing found in modules jetified-kotlin-stdlib-1.8.22 (org.jetbrains.kotlin:kotlin-stdlib:1.8.22) and jetified-kotlin-stdlib-jdk7-1.7.22 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.22)
     Duplicate class kotlin.io.path.PathNode found in modules jetified-kotlin-stdlib-1.8.22 (org.jetbrains.kotlin:kotlin-stdlib:1.8.22) and jetified-kotlin-stdlib-jdk7-1.7.22 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.22)
     Duplicate class kotlin.io.path.PathRelativizer found in modules jetified-kotlin-stdlib-1.8.22 (org.jetbrains.kotlin:kotlin-stdlib:1.8.22) and jetified-kotlin-stdlib-jdk7-1.7.22 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.22)
     Duplicate class kotlin.io.path.PathTreeWalk found in modules jetified-kotlin-stdlib-1.8.22 (org.jetbrains.kotlin:kotlin-stdlib:1.8.22) and jetified-kotlin-stdlib-jdk7-1.7.22 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.22)
     Duplicate class kotlin.io.path.PathTreeWalk$bfsIterator$1 found in modules jetified-kotlin-stdlib-1.8.22 (org.jetbrains.kotlin:kotlin-stdlib:1.8.22) and jetified-kotlin-stdlib-jdk7-1.7.22 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.22)
     Duplicate class kotlin.io.path.PathTreeWalk$dfsIterator$1 found in modules jetified-kotlin-stdlib-1.8.22 (org.jetbrains.kotlin:kotlin-stdlib:1.8.22) and jetified-kotlin-stdlib-jdk7-1.7.22 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.22)
     Duplicate class kotlin.io.path.PathTreeWalkKt found in modules jetified-kotlin-stdlib-1.8.22 (org.jetbrains.kotlin:kotlin-stdlib:1.8.22) and jetified-kotlin-stdlib-jdk7-1.7.22 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.22)
     Duplicate class kotlin.io.path.PathWalkOption found in modules jetified-kotlin-stdlib-1.8.22 (org.jetbrains.kotlin:kotlin-stdlib:1.8.22) and jetified-kotlin-stdlib-jdk7-1.7.22 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.22)
     Duplicate class kotlin.io.path.PathsKt found in modules jetified-kotlin-stdlib-1.8.22 (org.jetbrains.kotlin:kotlin-stdlib:1.8.22) and jetified-kotlin-stdlib-jdk7-1.7.22 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.22)
     Duplicate class kotlin.io.path.PathsKt__PathReadWriteKt found in modules jetified-kotlin-stdlib-1.8.22 (org.jetbrains.kotlin:kotlin-stdlib:1.8.22) and jetified-kotlin-stdlib-jdk7-1.7.22 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.22)
     Duplicate class kotlin.io.path.PathsKt__PathUtilsKt found in modules jetified-kotlin-stdlib-1.8.22 (org.jetbrains.kotlin:kotlin-stdlib:1.8.22) and jetified-kotlin-stdlib-jdk7-1.7.22 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.22)
     Duplicate class kotlin.jdk7.AutoCloseableKt found in modules jetified-kotlin-stdlib-1.8.22 (org.jetbrains.kotlin:kotlin-stdlib:1.8.22) and jetified-kotlin-stdlib-jdk7-1.7.22 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.22)
     Duplicate class kotlin.jvm.jdk8.JvmRepeatableKt found in modules jetified-kotlin-stdlib-1.8.22 (org.jetbrains.kotlin:kotlin-stdlib:1.8.22) and jetified-kotlin-stdlib-jdk8-1.7.10 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.7.10)
     Duplicate class kotlin.jvm.optionals.OptionalsKt found in modules jetified-kotlin-stdlib-1.8.22 (org.jetbrains.kotlin:kotlin-stdlib:1.8.22) and jetified-kotlin-stdlib-jdk8-1.7.10 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.7.10)
     Duplicate class kotlin.random.jdk8.PlatformThreadLocalRandom found in modules jetified-kotlin-stdlib-1.8.22 (org.jetbrains.kotlin:kotlin-stdlib:1.8.22) and jetified-kotlin-stdlib-jdk8-1.7.10 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.7.10)
     Duplicate class kotlin.streams.jdk8.StreamsKt found in modules jetified-kotlin-stdlib-1.8.22 (org.jetbrains.kotlin:kotlin-stdlib:1.8.22) and jetified-kotlin-stdlib-jdk8-1.7.10 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.7.10)
     Duplicate class kotlin.streams.jdk8.StreamsKt$asSequence$$inlined$Sequence$1 found in modules jetified-kotlin-stdlib-1.8.22 (org.jetbrains.kotlin:kotlin-stdlib:1.8.22) and jetified-kotlin-stdlib-jdk8-1.7.10 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.7.10)
     Duplicate class kotlin.streams.jdk8.StreamsKt$asSequence$$inlined$Sequence$2 found in modules jetified-kotlin-stdlib-1.8.22 (org.jetbrains.kotlin:kotlin-stdlib:1.8.22) and jetified-kotlin-stdlib-jdk8-1.7.10 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.7.10)
     Duplicate class kotlin.streams.jdk8.StreamsKt$asSequence$$inlined$Sequence$3 found in modules jetified-kotlin-stdlib-1.8.22 (org.jetbrains.kotlin:kotlin-stdlib:1.8.22) and jetified-kotlin-stdlib-jdk8-1.7.10 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.7.10)
     Duplicate class kotlin.streams.jdk8.StreamsKt$asSequence$$inlined$Sequence$4 found in modules jetified-kotlin-stdlib-1.8.22 (org.jetbrains.kotlin:kotlin-stdlib:1.8.22) and jetified-kotlin-stdlib-jdk8-1.7.10 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.7.10)
     Duplicate class kotlin.text.jdk8.RegexExtensionsJDK8Kt found in modules jetified-kotlin-stdlib-1.8.22 (org.jetbrains.kotlin:kotlin-stdlib:1.8.22) and jetified-kotlin-stdlib-jdk8-1.7.10 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.7.10)
     Duplicate class kotlin.time.jdk8.DurationConversionsJDK8Kt found in modules jetified-kotlin-stdlib-1.8.22 (org.jetbrains.kotlin:kotlin-stdlib:1.8.22) and jetified-kotlin-stdlib-jdk8-1.7.10 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.7.10)

     Go to the documentation to learn how to <a href="d.android.com/r/tools/classpath-sync-errors">Fix dependency resolution errors</a>.

* Try:
> Run with --stacktrace option to get the stack trace.
> Run with --info or --debug option to get more log output.
> Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 8s
Exception: Gradle task assembleDebug failed with exit code 1


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Answers


  1. Chosen as BEST ANSWER
    0

    adding this to build.gradle fixed the issue:

    configurations.all {
    resolutionStrategy {
        force 'org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.8.22'
    }
}

    I am assuming that this is forcing the library to upgrade its kotlin dependency. Is that a dangerous move? So far, it seems to work without issue.


  2. 0

    The problem you’re facing is with your Gradle dependencies, as you’ve pointed out.

    It seems that while you declare org.jetbrains.kotlin:kotlin-stdlib, they instead declare org.jetbrains.kotlin:kotlin-stdlib-jdk7, which happen to be different packages, with the same kinds of code. And while I can confirm that they do indeed have that dependency from their GitHub project, I cannot really see your code! So a bit of an assumption, here.

    Anyway, a solution would be for you to drop your version of Kotlin, and piggy-back theirs. Although, that may cause other unforeseen problems. Alternatively, you could consider downgrading your Kotlin plugin to match theirs.

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