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Fix typos in jvm-api-guidelines-backward-compatibility.md #3

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Fix typos in jvm-api-guidelines-backward-compatibility.md #3

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4 changes: 2 additions & 2 deletions docs/topics/jvm-api-guidelines-backward-compatibility.md
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Expand Up @@ -267,7 +267,7 @@ Let's change the return type of the "library" function `x()` from `Number` to `I
fun x(): Int = 3
```

And recompile only the client: `kotlinc client.kt`. `ClientKt` doesn't work as expected anymore. It doesn't print `3`
And recompile only the library: `kotlinc library.kt`. `ClientKt` doesn't work as expected anymore. It doesn't print `3`
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I don't think it's a typo or a mistake. It demonstrates that if you change the return type of a function in your library, the clients will need to re-compile their code against the new version of your library code.

The client code was compiled to call the function that returns Number. However, because the return type was changed from Number to Int, such function doesn't exist anymore, so it fails with NoSuchMethodError. This pretty much happens because java is dynamically linked.

I'll leave it to @asm0dey, maybe we could add some details to this section so that it doesn't raise such questions

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Yes, @IgnatBeresnev, it's correct. The backward compatibility issues mainly arise during split compilation, which we emulate in this example

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I think it depends on what do you compile the client.kt against, the source code (which was updated) or the binary (which is outdated). If compiled against the source code the error message should be java.lang.Integer instead of java.lang.Number, because the client was compiled against the version with the Int as return type. If compiled against the binary, there should no be any error, because the binary did not change and the client code was also not changed.

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@Legion2 The whole case was about split compilation, which is usually the case. Sometimes, it is in a more complex setup, but still.

and throws an exception instead:

```none
Expand Down Expand Up @@ -308,7 +308,7 @@ so that your user is able to consciously choose what API they want to use and wh

Another example of `@RequiresOptIn` is when you want to explicitly warn users about the usage of some API. For example,
if you maintain a library that utilizes Kotlin reflection, you can annotate classes in this library
with `@OptIn(RequiresFullKotlinReflection::class)`.
with `@RequiresOptIn(RequiresFullKotlinReflection::class)`.
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## Explicit API mode

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