JVM: Logging cannot be configured (PagingLogger spams output)

[biberesser]

Great work guys with the library, but currently there is a small problem:

Paging version: 3.3.0-alpha02-0.5.1
Platform: JVM

The built-in logging cannot be configured.
This leads to thousands of lines of VERBOSE and DEBUG output.

Currently the JVM PagingLogger is hardwired for some reason: isLoggable() always returns true.

PagingLogger.jvm.kt:

package androidx.paging

import androidx.annotation.RestrictTo

@RestrictTo(RestrictTo.Scope.LIBRARY_GROUP)
public actual object PagingLogger {

    public actual fun isLoggable(level: Int): Boolean {
        return true
    }

    // consider using java.util.logging APIs instead
    public actual fun log(level: Int, message: String, tr: Throwable?) {
        print("\n$message")
    }
}

example log spam when scrolling a paginated list:

Generated new PagingSource my.package.MyOffsetQueryMappedPagingSource@58e7f207
Sent PageEvent.LoadStateUpdate (
   sourceLoadStates: LoadStates(refresh=Loading(endOfPaginationReached=false), prepend=NotLoading(endOfPaginationReached=false), append=NotLoading(endOfPaginationReached=false))
)
Collected PageEvent.LoadStateUpdate (
   sourceLoadStates: LoadStates(refresh=Loading(endOfPaginationReached=false), prepend=NotLoading(endOfPaginationReached=false), append=NotLoading(endOfPaginationReached=false))
)
Start REFRESH with loadKey null my.package.MyOffsetQueryMappedPagingSource@58e7f207
End REFRESH with loadKey null. Returned LoadResult.Page(
   data size: 1500
   first Item: MyItem(...)
   last Item: MyItem(...)
   nextKey: 1500
   prevKey: null
   itemsBefore: 0
   itemsAfter: 2691
) 
Sent PageEvent.Insert for REFRESH, with 1500 items (
   first item: MyItem(...)
   last item: MyItem(...)
   placeholdersBefore: 0
   placeholdersAfter: 2691
   sourceLoadStates: LoadStates(refresh=NotLoading(endOfPaginationReached=false), prepend=NotLoading(endOfPaginationReached=true), append=NotLoading(endOfPaginationReached=false))
)
Collected PageEvent.Insert for REFRESH, with 1500 items (
   first item: MyItem(...)
   last item: MyItem(...)
   placeholdersBefore: 0
   placeholdersAfter: 2691
   sourceLoadStates: LoadStates(refresh=NotLoading(endOfPaginationReached=false), prepend=NotLoading(endOfPaginationReached=true), append=NotLoading(endOfPaginationReached=false))
)
Presenting data:
   first item: MyItem(...)
   last item: MyItem(...)
   placeholdersBefore: 0
   placeholdersAfter: 2691
   hintReceiver: androidx.paging.PageFetcher$PagerHintReceiver@36d82710
   sourceLoadStates: LoadStates(refresh=NotLoading(endOfPaginationReached=false), prepend=NotLoading(endOfPaginationReached=true), append=NotLoading(endOfPaginationReached=false))
)PAGING ITEMS: LoadStateNotLoading: NotLoading(endOfPaginationReached=false)
PAGING ITEMS: LoadStateNotLoading: NotLoading(endOfPaginationReached=false)
PAGING ITEMS: LoadStateNotLoading: NotLoading(endOfPaginationReached=false)

Accessing item index[0]
Accessing item index[1]
Accessing item index[2]
Accessing item index[3]
Accessing item index[4]
Accessing item index[5]
Accessing item index[6]
Accessing item index[7]
Accessing item index[8]
Accessing item index[9]
Accessing item index[10]
Accessing item index[11]
Accessing item index[12]
Accessing item index[13]
Accessing item index[14]
Accessing item index[15]
Accessing item index[16]
Accessing item index[17]
Accessing item index[18]
Accessing item index[19]
Accessing item index[20]
Accessing item index[21]

[JakeWharton]

Should be easy to switch to Logger. Want to send a PR? No one is currently working on this repo, but I'd merge a fix if someone else wanted to contribute it.

[srideep-banerjee]

@JakeWharton Hello I ran into the same issue. can you please tell me how I can change the logger?

[JakeWharton]

Until you or somebody sends a PR to switch to Logger and there is a release you cannot change it.

[starxg]

1. pom.xml

<dependency>
    <groupId>androidx.paging</groupId>
    <artifactId>paging-common-jvm</artifactId>
    <version>1.14</version>
    <scope>3.3.0-alpha02</scope>
    <systemPath>your local path paging-common-jvm-3.3.0-alpha02.jar</systemPath>
</dependency>

2. FixPagingLogger.java

import javassist.ClassPool;
import javassist.CtClass;
import javassist.CtMethod;
import org.apache.commons.io.IOUtils;
import org.junit.Test;

import java.nio.file.Files;
import java.nio.file.Paths;

public class FixPagingLogger {
    @Test
    public void test() throws Exception {
        final ClassPool pool = ClassPool.getDefault();
        final CtClass clazz = pool.get("androidx.paging.PagingLogger");
        final CtMethod method = clazz.getDeclaredMethod("isLoggable");
        method.setBody("return false;");
        IOUtils.write(clazz.toBytecode(), Files.newOutputStream(Paths.get("PagingLogger.class")));
        clazz.detach();
    }
}

3. Open paging-common-jvm-3.3.0-alpha02.jar with 7-zip
4. Replace the androidx.paging.PagingLogge file
5. It works by modifying the Class bytecode so that the isLoggable method returns false.

---

build.gradle.kts(IMPORTANT!!!)

implementation("app.cash.paging:paging-compose-common:3.3.0-alpha02-0.5.1") {
    exclude(group = "androidx.paging", module = "paging-common-jvm")
}
// Here we introduce the modified paging-common-jvm-3.3.0-alpha02.jar file
implementation(fileTree("${projectDir}/libs"))

---

THIS IS MY MODIFIED JAR FILE (I SUGGEST YOU DON'T TRUST ANY UNOFFICIAL JAR FILE, YOU NEED TO GO THROUGH IT MANUALLY YOURSELF)

paging-common-jvm-3.3.0-alpha02-rm-log.jar.zip

[zt64]

@JakeWharton

I had reported to Google this issue and still nothing's been done. I'll make a PR, that should be okay until Google hopefully does something?