Berlindroid: Naming is Hard

Naming is hard, it's no unfamiliar thing to software engineers that describing our software can sometimes be just as hard as writing it in the first place. But did you know that the names we give our well-intentioned ideas can come back to haunt us?

It would turn out that naming is not just hard, but it has implications! Gradle will often not actually report when names collide! Which means you might end up with unexpected class resolutions! Which leads us down the rabbit hole of, how does Java resolve classes in the first place?!

This talk is a work in progress, I'll show you my problem-solving approach, and what discoveries I made along the way to find out that, well, naming is indeed, hard.

Transcript

1. Naming is Hard How Naming Can Bite You in the Ass Berlindroid - Feb ‘24 󰎲 Ash Davies Android / Kotlin GDE - Berlin ashdavies.dev Kotti
2. “There are only two hard things in computer science…” – Everyone
3. Naming is Hard… Py
4. Stable (1.9.20) Kotlin Multiplatform
7. 🔒
8. 🔒
9. Kotlin Multiplatform
10. Compose Kotlin Multiplatform
11. Kotlin Multiplatform
12. commonMain Expected and actual declarations Kotlin Multiplatform public data class File(public val path: String) public fun File.print(): String = "File: $path" public expect fun createNewFile(): File
13. androidMain / jvmMain Expected and actual declarations Kotlin Multiplatform public actual fun createNewFile(): File { return File(createTempFile().toString()) }
14. Expected and actual declarations Kotlin Multiplatform
15. Expected and actual declarations Kotlin Multiplatform > Task :shared:compileDebugKotlinAndroid FAILED e: file:///shared/src/androidMain/kotlin/io/ashdavies/shared/File.kt:1:1 Duplicate JVM class name 'io/ashdavies/shared/FileKt' generated from: FileKt, FileKt e: file:///shared/src/commonMain/kotlin/io/ashdavies/shared/File.kt:1:1 Duplicate JVM class name 'io/ashdavies/shared/FileKt' generated from: FileKt, FileKt 🔥🔥🔥
16. Expected and actual declarations @file:JvmName("FileJvm") Kotlin Multiplatform
17. Expected and actual declarations github.com/JetBrains/compose-multiplatform /blob/master/examples/imageviewer /shared/src/androidMain/kotlin /example/imageviewer /platform.android.kt Kotlin Multiplatform
18. Expected and actual declarations youtrack.jetbrains.com/issue/KT-21186 Kotlin Multiplatform 👍
19. Extensions Resolved Statically Kotlin Multiplatform public data class File(public val path: String) { private val segments = path.split("/") } // Does not compile! public fun File.printSegments() { segments.forEach { println(it) } }
20. Extensions Resolved Statically Kotlin Multiplatform public data class File(public val path: String) public val File.extension: String get() = path.substringAfterLast(".")
21. Extensions Kotlin Multiplatform
22. Extensions Kotlin Multiplatform Exception in thread "main" java.lang.NoSuchMethodError: 'io.ashdavies.playground.File io.ashdavies.playground.File_jvmKt.createNewFile()' FATAL EXCEPTION: main Process: io.ashdavies.playground, PID: 28922 java.lang.NoSuchMethodError: No static method createNewFile()Lio/ashdavies/playground/File; in class Lio/ashdavies/playground/File_androidKt; or its super classes (declaration of 'io.ashdavies.playground.File_androidKt' appears in /data/data/io.ashdavies.playground/code_cache/.overlay/ba se.apk/classes17.dex) 🔥🔥🔥 Desktop Android
23. Collisions File.kt Kotlin Multiplatform FileKt.kt FileKtKt.kt FileKtKtKt.kt FinalFileKtKt.kt FinalNoIMeanItThisTimeKtKtKt.kt
24. Namespacing Kotlin Multiplatform 👍
25. Modularisation
26. Modularisation developer.android.com/topi c/modularization/patterns Gradle Modules
27. Modularisation “Modularise all the things!”
28. droidcon.com/2023/11/15/ structuring-modules-in- an-android-app-project/ Structuring modules in an Android app project
29. Modularisation Gradle Modules project :feature-login :feature-profile
30. Modularisation Gradle Modules project :feature-login:google :feature-profile:shared :feature-login:shared :feature-login :feature-profile :feature-profile:ui
31. Modularisation Gradle Modules project :feature-login:google :feature-profile:shared :feature-login:shared :feature-login :feature-profile :feature-profile:ui
32. Project Naming Conflict github.com/gradle/gradle/issues/847 Gradle
33. Collisions
34. Impact
35. C / Java 😭 Conventions
36. Archaic Conventions public interface ViewStateFactory { fun create(): ViewState } public class ViewStateFactoryImpl : ViewStateFactory { override fun create(): ViewState { TODO() } } Impl Suffix
37. Archaic Conventions public interface AppServiceBinderHandlerCallbackFactory Java Suffixes
38. Archaic Conventions Hungarian Notation 󰢃
39. Unclear Intentions for (i: Int in kS) { try { c.connect(i) } catch (e: Throwable) { // Meh 󰤇 } } Single letter names
40. Meaningful Naming internal suspend infix fun String.contains(value: String): Boolean Signatures
41. Meaningful Naming fun updateClaimWithPolicyDetails(c: Claim, pc: PolicyCriteria, identifier: String) fun getIfNotSetWithDefault(value: Any): String fun compareAndSet(value: Any): Boolean fun isNullOrEmpty(value: String): Boolean Command / Query
42. Meaningful Naming Victims Junior developers New team members Future you
43. “Always code as if the guy [sic] who ends up maintaining your code will be a violent psychopath who knows where you live” - John Woods
44. Language 🗣 󰎼 ¿Qué tal? 󰧻 Helô 󰏃 Salut! 󰑒 Pryvit 󰏅 Hello! 󰏢 Ciao 󰎩 Nǐ hǎo 󰎲 Hallo 󰐨 Oi 󰎺 Ahlan 󰏮Anyoung 󰐴 Hej 󰏏 Yassou 󰑍 Selam
45. Programming in English Multilingualism
46. 🗣 Multilingualism
47. fun showCancelBookingAndBackToVerbindungsuebersichtDialog() fun handleLoadBuchungskundenDatenOrOpenRechnungFailure() fun getAngebotsKonditionIconAndContentDescription()
48. # -*- coding: iso-8859-1 -*- schön = Wahr häßlich = Falsch für bäh in [schön, häßlich]: drucke bäh def sovielwiemöglich(): "gib" zurück "was mir gehört"
49. Don’t repeat yourself, avoid naming collisions Consider causes for ambiguous error messages Scrutinise naming conventions Understand idioms for the language Takeaways
50. Thanks! Ash Davies - Cat Person Android / Kotlin GDE - Berlin ashdavies.dev