KMP4FREE in 2023 @ Droidcon NYC 2022

Video: https://www.droidcon.com/2022/09/29/kmp4free-in-2023/

At Droidcon SF 2022, I first publicly announced the KMP4FREE Gradle Plugin and how it can be used to seamlessly toggle between the Kotlin JVM and Kotlin Multiplatform Plugins with a single line change. In this talk I'll show you what this will look like over the next year, and more real world examples of how this Gradle Plugin can be used. KMP4FREE can help you can start making your Kotlin code Multiplatform Compatible, today!

Transcript

1. Sam Edwards - @HandstandSam Kotlin & Android GDE @ Dropbox KMP4FREE in 2023 Droidcon NYC 2022
2. Sam Edwards - @HandstandSam Kotlin & Android GDE @ Dropbox Multiplaformization in 2023 Droidcon NYC 2022
3. https://twitter.com/relizarov/status/1564288780261068802 KMP4FREE is a Tool to help with Multiplatformization
4. K 4FREE MP
5. Primary Goals of KMP4FREE • No Risk, Single Line Change to Enable Multiplatform • Support JVM & Multiplatform Con fi g • Allow Experimentation and Possible Migration to Multiplatform
6. KMP4FREE Work? How Does
7. JVM Project Structure plugins { kotlin("jvm") } dependencies { implementation(libs.kotlin.stdlib) implementation(project(":samples:jvm_kmp4free")) testImplementation(libs.kotlin.test.common) testImplementation(libs.truth) }
8. JVM Project Structure plugins { id("com.handstandsam.kmp4free") } dependencies { implementation(libs.kotlin.stdlib) implementation(project(":samples:jvm_kmp4free")) testImplementation(libs.kotlin.test.common) testImplementation(libs.truth) }
9. Enable/Disable with Property # gradle.properties kmp4free=true or ./gradlew … -Pkmp4free=true
10. JVM Project Structure
11. JVM Project Structure
12. JVM Project Structure kmp4free=false
13. JVM Project Structure kmp4free=true kmp4free=false
14. JVM Project Structure kmp4free=true kmp4free=false
15. JVM Project Structure kmp4free=true kmp4free=false
16. Source Set and Con fi guration Mapping How?
17. kmp4free=true • SourceSet Mapping • src/main ➡ src/commonMain • src/test ➡ src/jvmTest • Con fi guration Mapping • implementation ➡ commonMainImplementation • testImplementation ➡ jvmTestImplementation • Task Aliasing • :module:test ➡ :module:jvmTest
18. kmp4free=false • SourceSet Mapping • src/commonMain ➡ src/main • src/jvmMain ➡ src/main • src/commonTest ➡ src/test • src/jvmTest ➡ src/test • Con fi guration Mapping • commonMainImplementation ➡ implementation • commonTestImplementation ➡ testImplementation • jvmTestImplementation ➡ testImplementation
19. K 4FREE MP Demo
20. Enable and Disable Multiplatform Targets? Can’t You Just
21. Compiling Multiplatform Can Be Slow https://medium.com/yazio-engineering/speeding-up-kotlin-multiplatform-61ebf8dae560 grade.properties
22. Multiplatform Doesn’t Support Con fi guration Caching (Yet) https://youtrack.jetbrains.com/issue/KT-49933/Support-Gradle-Con fi guration-caching-with-HMPP
23. Multiplatform Plugin Adds Overhead 7 Tasks 14 Tasks
24. Doesn’t Quite Work in Android Studio https://issuetracker.google.com/issues/229628556
25. KMP4FREE? Should I Use
26. but NOT Inde fi nitely It Depends
27. to Multiplatform Finding Your Path
28. Paths to Multiplatformization New Code
29. Paths to Multiplatformization commonMain New Code
30. Paths to Multiplatformization commonMain Existing Code New Code
31. Paths to Multiplatformization Existing Code commonMain New Code KMP4FREE?
32. Paths to Multiplatformization Existing Code commonMain KMP4FREE?
33. Shapes The Future Every Decision
34. Has Consequences Every Decision
35. On Kotlin Going All In
36. On Compose Going All In
37. On Multiplatform Going All In
38. Mitigation Risk
39. From The Past Learn
40. 🤔 https://dropbox.tech/mobile/the-not-so-hidden-cost-of-sharing-code-between-ios-and-android
41. “By writing code in a non-standard fashion, we took on overhead that we would have not had to worry about had we stayed with the widely used platform defaults. This overhead ended up being more expensive than just writing the code twice.”
42. The Overhead of: 1. Custom frameworks and libraries 2. Custom development environment 3. Addressing di ff erences between the platforms 4. Training, hiring, and retaining developers
43. Write Kotlin Multiplatform Code? When Will Your Team
44. with KMP4FREE Starting Now
45. Ship Kotlin Multiplatform Code on iOS? When Will Your Team
46. Maybe Never? ¯\_(ツ)_/¯
47. For Kotlin Multiplatform Plant a Seed 🌱
48. …And It Might Grow 🌲
49. Plant a Seed 🌱 • Same Kotlin Code • Di ff erent Gradle plugin • Forces modularity • Makes developers more likely to try coding in the other platform
50. Identifying Target Projects
51. Plugins Kotlin + Gradle
52. Gradle Plugin Migration kotlin(“android”)
53. Gradle Plugin Migration kotlin(“android”) kotlin(“jvm”)
54. Gradle Plugin Migration kotlin(“android”) kotlin(“jvm”) kotlin(“multiplatform”)
55. Android Library Kotlin JVM Step 1 ➡
56. dependency-analysis-android-gradle-plugin github.com/autonomousapps/dependency-analysis-android-gradle-plugin
57. dependency-analysis-android-gradle-plugin 1. Gathers Module Data 2. Runs Decisioning Logic 3. Shares Actionable Advice
58. data class AndroidScore( val hasAndroidAssets: Boolean, val hasAndroidRes: Boolean, val usesAndroidClasses: Boolean, val hasBuildConfig: Boolean, val hasAndroidDependencies: Boolean, ) : ModuleAdvice() { Android Library ➡ JVM Module Advice
59. data class AndroidScore( val hasAndroidAssets: Boolean, val hasAndroidRes: Boolean, val usesAndroidClasses: Boolean, val hasBuildConfig: Boolean, val hasAndroidDependencies: Boolean, ) : ModuleAdvice() { Android Library ➡ JVM Module Advice
60. data class AndroidScore( val hasAndroidAssets: Boolean, val hasAndroidRes: Boolean, val usesAndroidClasses: Boolean, val hasBuildConfig: Boolean, val hasAndroidDependencies: Boolean, ) : ModuleAdvice() { Android Library ➡ JVM Module Advice
61. data class AndroidScore( val hasAndroidAssets: Boolean, val hasAndroidRes: Boolean, val usesAndroidClasses: Boolean, val hasBuildConfig: Boolean, val hasAndroidDependencies: Boolean, ) : ModuleAdvice() { Android Library ➡ JVM Module Advice
62. data class AndroidScore( val hasAndroidAssets: Boolean, val hasAndroidRes: Boolean, val usesAndroidClasses: Boolean, val hasBuildConfig: Boolean, val hasAndroidDependencies: Boolean, ) : ModuleAdvice() { Android Library ➡ JVM Module Advice
63. data class AndroidScore( val hasAndroidAssets: Boolean, val hasAndroidRes: Boolean, val usesAndroidClasses: Boolean, val hasBuildConfig: Boolean, val hasAndroidDependencies: Boolean, ) : ModuleAdvice() { Android Library ➡ JVM Module Advice
64. @TypeLabel("android_score") @JsonClass(generateAdapter = false) data class AndroidScore( val hasAndroidAssets: Boolean, val hasAndroidRes: Boolean, val usesAndroidClasses: Boolean, val hasBuildConfig: Boolean, val hasAndroidDependencies: Boolean, ) : ModuleAdvice() { @delegate:Transient private val score: Float by unsafeLazy { var count = 0f if (hasAndroidAssets) count += 2 if (hasAndroidRes) count += 2 if (usesAndroidClasses) count += 2 if (hasBuildConfig) count += 0.5f if (hasAndroidDependencies) count += 0.5f count } Android Library ➡ JVM Module Advice
65. @TypeLabel("android_score") @JsonClass(generateAdapter = false) data class AndroidScore( val hasAndroidAssets: Boolean, val hasAndroidRes: Boolean, val usesAndroidClasses: Boolean, val hasBuildConfig: Boolean, val hasAndroidDependencies: Boolean, ) : ModuleAdvice() { @delegate:Transient private val score: Float by unsafeLazy { var count = 0f if (hasAndroidAssets) count += 2 if (hasAndroidRes) count += 2 if (usesAndroidClasses) count += 2 if (hasBuildConfig) count += 0.5f if (hasAndroidDependencies) count += 0.5f count } Android Library ➡ JVM Module Advice
66. /** True if this project uses no Android facilities at all. */ fun shouldBeJvm(): Boolean = score == 0f Android Library ➡ JVM Module Advice @TypeLabel("android_score") @JsonClass(generateAdapter = false) data class AndroidScore( val hasAndroidAssets: Boolean, val hasAndroidRes: Boolean, val usesAndroidClasses: Boolean, val hasBuildConfig: Boolean, val hasAndroidDependencies: Boolean, ) : ModuleAdvice() { @delegate:Transient private val score: Float by unsafeLazy { var count = 0f if (hasAndroidAssets) count += 2 if (hasAndroidRes) count += 2 if (usesAndroidClasses) count += 2 if (hasBuildConfig) count += 0.5f if (hasAndroidDependencies) count += 0.5f count }
67. /** True if this project uses no Android facilities at all. */ fun shouldBeJvm(): Boolean = score == 0f /** True if this project only uses some limited number of Android facilities. */ fun couldBeJvm(): Boolean = score < THRESHOLD Android Library ➡ JVM Module Advice @TypeLabel("android_score") @JsonClass(generateAdapter = false) data class AndroidScore( val hasAndroidAssets: Boolean, val hasAndroidRes: Boolean, val usesAndroidClasses: Boolean, val hasBuildConfig: Boolean, val hasAndroidDependencies: Boolean, ) : ModuleAdvice() { @delegate:Transient private val score: Float by unsafeLazy { var count = 0f if (hasAndroidAssets) count += 2 if (hasAndroidRes) count += 2 if (usesAndroidClasses) count += 2 if (hasBuildConfig) count += 0.5f if (hasAndroidDependencies) count += 0.5f count }
68. Module Advice from ./gradlew buildHealth Advice for :samples:android_lib Module structure advice This project uses limited Android features and could be a JVM project. * Includes BuildConfig.
69. Refactoring is Rarely Trivial
70. Extract Android Specific Code • Android Classes • BuildCon fi g • Assets • Strings • Activities • Layouts • Drawables
71. Kotlin JVM Kotlin Multiplatform Step 2 ➡
72. KMP-Readiness github.com/handstandsam/kmp-readiness
73. KMP-Readiness Decisioning 1. Multiplatform Plugin Already Enabled? 2. Only Kotlin Code? 3. References to java.util, etc? 4. Multiplatform Compatible Dependencies?
74. Multiplatform Compatible Dependencies?
78. 9 Days Later …
80. Maven Search https://search.maven.org/search?q=ktor-client
81. Maven Search JSON API https://search.maven.org/solrsearch/select?q=g%3Aorg.jetbrains.kotlinx+AND+a%3Akotlinx-datetime+AND+v%3A0.3.2+AND+p%3Ajar+AND+l%3Akotlin-tooling-metadata&rows=1&wt=json { "response": { "numFound": 1, "start": 0, "docs": [ { "id": "org.jetbrains.kotlinx:kotlinx-datetime:0.3.2", "g": "org.jetbrains.kotlinx", "a": "kotlinx-datetime", "v": "0.3.2", "p": "jar", "timestamp": 1641926665000, "ec": [ "-javadoc.jar", "-sources.jar", ".jar", "-all.jar", "-kotlin-tooling-metadata.json", ".module", ".pom" ], "tags": [ "kotlin", "library", "datetime" ] } ] } } https://search.maven.org/search?q=g:org.jetbrains.kotlinx%20AND%20a:kotlinx-datetime%20AND%20v:0.3.2%20AND%20p:jar%20AND%20l:kotlin-tooling-metadata
82. Maven Search JSON API https://search.maven.org/solrsearch/select?q=g%3Aorg.jetbrains.kotlinx+AND+a%3Akotlinx-datetime+AND+v%3A0.3.2+AND+p%3Ajar+AND+l%3Akotlin-tooling-metadata&rows=1&wt=json "-kotlin-tooling-metadata.json"
83. kotlin-metadata-tooling.json
84. { "schemaVersion": "1.0.0", "buildSystem": "Gradle", "buildSystemVersion": "7.5.1", "buildPlugin": "org.jetbrains.kotlin.gradle.plugin.KotlinMultiplatformPluginWrapper", "buildPluginVersion": "1.6.21", "projectSettings": { "isHmppEnabled": true, "isCompatibilityMetadataVariantEnabled": true }, "projectTargets": [ { "target": "org.jetbrains.kotlin.gradle.targets.jvm.KotlinJvmTarget", "platformType": "jvm", "extras": { "jvm": { "jvmTarget": "1.8", "withJavaEnabled": false } } }, { "target": "org.jetbrains.kotlin.gradle.plugin.mpp.KotlinMetadataTarget", "platformType": "common" } ] } kotlin-tooling-metadata.json https://repo1.maven.org/maven2/io/ktor/ktor-client/2.1.0/ktor-client-2.1.0-kotlin-tooling-metadata.json
85. "platformType": "common" kotlin-tooling-metadata.json https://repo1.maven.org/maven2/io/ktor/ktor-client/2.1.0/ktor-client-2.1.0-kotlin-tooling-metadata.json
86. See Created kotlin-tooling-metadata.json for the Kotlin Team
87. February 2nd, 2021 - Kotlin Lang Slack
88. kdoctor https://github.com/Kotlin/kdoctor
89. KMP-readiness github.com/handstandsam/kmp-readiness Demo
90. …
91. Kotlin Multiplatform Multiplatformization Success!
92. What’s the Cost?
93. Upfront Investment, Low Risk, …
94. Run Anywhere* Write Once * Yes, but…
95. Coming Soon! Kotlin Multiplatform Beta
96. Minimize Risk during Multiplatformization We Can
97. Test and Experiment ♻ • Create a multiplatform iOS and Desktop app that exercises it • Create Shadow Jobs to Build Multiplatform to ensure compatibility
98. 2023 is the Year of Multiplatformization
99. Is a helpful tool on your path to Multiplaformization in 2023 KMP4FREE
100. Is a helpful tool on your path to Multiplaformization in 2023 KMP-Readiness
101. With Multiplatform in Mind Write Code
102. Thank You