Hi I am trying to migrate a Gradle Groovy DSL to Kotlin DSL

Question

Hi I am trying to migrate a Gradle Groovy DSL to Kotlin DSL and I am trying to declare dependencies in buildSrc in a way similar to this <https proandroiddev com gradle dependency management with kotlin 94eed4df9a28 > The problem is that I have some dependencies that are not just the simple artifact and version and need some extra configuration On the Groovy DSL I used code like this ``` dep = dependencies create com squareup retrofit2 converter simplexml + constants versions retrofit We need to exclude dependencies which are already provided by the Android platform exclude module stax api exclude module stax exclude module xpp3 ``` But I can t figure out how to convert that to Kotlin DSL and I don t even have access to the dependencies create method on the buildSrc object where I am declaring the dependencies Is it possible to define a dependency with exclusions like that outside a DependencyHandler scope Is there a standalone constructor builder for dependencies that is not an extension method only available at specific places

gildor · Answer

In this case you have not just version but config snippet also you need dependencies object to do that So possible way just extract it to extension function for dependencies and apply where you need this

gildor · Answer

But I believe you need this only if you use it multiple times in different modules otherwise easier just define in it on place

jrgonzalez · Answer

Yes I want it for multi module projects to declare dependencies with its configuration only once The problem with the extension function would be that I can not declare it on a big Dependencies object and access it like `Dependencies retrofit2ConverterSimpleXML` as the ones that I have with no configuration Also don t know how to do the configuration like in Groovy

gildor · Answer

Problem that you need project instance to create dependency

gildor · Answer

So or it should be extension function or retrofit2ConverterSimpleXML must be function not a property

gildor · Answer

And you pass DependencyHandler or Project instance you just cannot resolve it statically you need instance of DependencyHandler to create dependency

jrgonzalez · Answer

it does not seem to work if a declare it as `fun DependencyHandler retrofit2ConverterSimpleXML ` inside the Dependencies object

gildor · Answer

Why

jrgonzalez · Answer

If I try to autocomplete in a line like `implementation Dependencies ` I don t get the function appearing at all

jrgonzalez · Answer

neither it works as `implementation Dependencies retrofit2ConverterSimpleXML ` or offers anything to import as `implementation retrofit2ConverterSimpleXML `

gildor · Answer

Maybe just some tooling problem if you have function in buildSrc it must be available on you build gradle

jrgonzalez · Answer

yeah after several tries now I got the last one `implementation retrofit2ConverterSimpleXML ` to offer to import it as `import Dependencies retrofit2ConverterSimpleXML` but that is not ideal either cause I lose autocompletion so I have to look them up on the object manually and also to add imports which the other dependencies do not need

jrgonzalez · Answer

Why is a project DependencyHandler needed for creating a dependency when it is not used on creation

jrgonzalez · Answer

shouldn t it just be a simple object model

gildor · Answer

Apparently it used create is method of DependencyHandler

gildor · Answer

You shouldn t import Dependencies not sure what is exactly you problem If your Dependencies object uses default package it just should work same for any top level extension

jrgonzalez · Answer

yeah I saw that but it may be just a convenience extension and it could be possible to create it in some other way that is not scoped to DependencyHandler but I haven t found any doc about that

jrgonzalez · Answer

Also the config does not work easily it expects a Closure lt Any gt

gildor · Answer

If you have ```object Dependencies fun retrofitSimpleXml dep DependencyHandler ``` Than I don t see any problem

jrgonzalez · Answer

maybe doing `closureOf lt ExternalModuleDependency gt ` sweat smile

jrgonzalez · Answer

oh so no extension function but a function receiving the dependency handler

jrgonzalez · Answer

How that would be called `Dependencies retrofitSimpleXml this `

gildor · Answer

Yes

gildor · Answer

Extension function is just an option it s easier to use but you right it s not related anymore to your Dependencies object

gildor · Answer

gt Also the config does not work easily it expects a Closure lt Any gt Just create dependency cast it to ExternalDependency and use apply to configure

jrgonzalez · Answer

This seems to compile ``` fun retrofit2ConverterSimpleXML dependencyHandler DependencyHandler Dependency = dependencyHandler create com squareup retrofit2 converter simplexml$ Versions retrofit closureOf lt ExternalModuleDependency gt exclude module = stax api exclude module = stax exclude module = xpp3 ```

jrgonzalez · Answer

but not on usage sweat smile

jrgonzalez · Answer

does not accept this later `implementation Dependencies retrofitConverterSimplexml this `

jrgonzalez · Answer

` ^ Type mismatch inferred type is Dependency but Any was expected``

gildor · Answer

Your dependency is nullable

gildor · Answer

Not sure why

gildor · Answer

Looks that your code explicitly defines it as non nullable

jrgonzalez · Answer

also tried this based on what you said ``` fun retrofit2ConverterSimpleXML dependencyHandler DependencyHandler Dependency = dependencyHandler create com squareup retrofit2 converter simplexml$ Versions retrofit as ExternalDependency apply exclude module = stax api exclude module = stax exclude module = xpp3 ```

gildor · Answer

It s the same

jrgonzalez · Answer

it also compiles that part but fails with same error on implementation reference

gildor · Answer

Check why dependency is nullable

gildor · Answer

It just doesn t allow to pass nullable

gildor · Answer

But I don t see the reason

gildor · Answer

Just for test add To usage

jrgonzalez · Answer

it seems not that but that implementation expects either any or 2 parameters one of which is a Dependency

jrgonzalez · Answer

so it is going to ```fun DependencyHandler `implementation` dependencyNotation Any Dependency ```

jrgonzalez · Answer

instead of ```fun lt T ModuleDependency gt DependencyHandler `implementation` dependency T dependencyConfiguration T gt Unit T```

gildor · Answer

Ah I see

gildor · Answer

Yeah type safe accessor generated oy for string

gildor · Answer

You have to use ```add implementation dependency ```

gildor · Answer

Maybe you can solve this in another way and just globally exclude those dependencies for all modules instead attaching this to your dependency definition

jrgonzalez · Answer

same complain sweat smile

gildor · Answer

Sorry I confused

gildor · Answer

Where is type mismatch

jrgonzalez · Answer

that one also expects a Any

jrgonzalez · Answer

not a Dependency

gildor · Answer

Any is super type of Dependency

gildor · Answer

So it s fine

gildor · Answer

Your problem with nullability

gildor · Answer

Not with class

jrgonzalez · Answer

I don t know how to get it to use this one ``` fun lt T ModuleDependency gt DependencyHandler `implementation` dependency T dependencyConfiguration T gt Unit T ```

jrgonzalez · Answer

seem that is the one that allows to pass a Dependency as the created one

gildor · Answer

Pass empty lambda

jrgonzalez · Answer

but since it expects a second parameter

gildor · Answer

Second param just an empty lambda

gildor · Answer

implementation dependency

jrgonzalez · Answer

like this `implementation Dependencies retrofitConverterSimplexml this `

jrgonzalez · Answer

also tried but it then gives this different error

jrgonzalez · Answer

``` implementation Dependencies retrofitConverterSimplexml this ^ None of the following functions can be called with the arguments supplied public fun lt T Dependency gt DependencyHandler implementation dependency TypeVariable T action Action lt TypeVariable T gt TypeVariable T defined in org gradle kotlin dsl public fun DependencyHandler implementation group String name String version String = configuration String = classifier String = ext String = dependencyConfiguration Action lt ExternalModuleDependency gt = ExternalModuleDependency defined in org gradle kotlin dsl public fun DependencyHandler implementation dependencyNotation String dependencyConfiguration Action lt ExternalModuleDependency gt ExternalModuleDependency defined in org gradle kotlin dsl ```

gildor · Answer

I m away from my PC and IDE just check types that possible to pass to type safe accessors and to dynamic add setters one of them should allow pass Dependency

gildor · Answer

Probably your method should return ExternalDependency not sure

jrgonzalez · Answer

ok thanks it has been really helpful at least looks there is some path this way slightly smiling face I will keep tinkering

gildor · Answer

Ahh correct I see it now in generic function that you showed above only for module dependencies not for external dependency

gildor · Answer

I still think that global configuration resolution is just better solution

jrgonzalez · Answer

but the odd thing is that with Groovy it works

gildor · Answer

Exclude those dependencies from all modules in allproject block

gildor · Answer

This also will work

jrgonzalez · Answer

I mean I can pass a dependency created with the create method to implementation and it just takes it

gildor · Answer

Because groovy dynamic try to use `add ` it probably also will work

gildor · Answer

It should have compatible overload for this case

gildor · Answer

But usage of not type safe `add` Imo just destroying all the idea of type safe dependency definition

gildor · Answer

So global configuration resolution strategy imo the best keeps your dependency definition and usage simple and obvious

gildor · Answer

Also solves problem of transitive dependencies which also can bring excluded dependencies

jrgonzalez · Answer

yes it kinda also feels like if somehow the Groovy variant of implementation method allowing what I did before is not accesible through the Kotlin DSL

jrgonzalez · Answer

there are some calls of add with an ExternalModuleDependency but it requires like 3 parameters sweat smile

jrgonzalez · Answer

oh not even that is not an ExternalModuleDependency but its configuration

jrgonzalez · Answer

so I guess yes I should go the global route

jrgonzalez · Answer

this also seems to work ```implementation Dependencies retrofitConverterSimplexml exclude module = stax api exclude module = stax exclude module = xpp3 ```

jrgonzalez · Answer

which would mean basic unconfigured dependency declaration and duplicated config block per usage

gildor · Answer

add implementation is the same as implementation But in both cases you lose type safety

jrgonzalez · Answer

yes deleted cause I think it was wrong was trying to trick it to use the groovy version of implementation that supports a dependency as single parameter sweat smile

jrgonzalez · Answer

it seems to accept several things but I can not fully compile the project yet to be sure they are valid and doing what I intend This compiles too ``` withGroovyBuilder implementation $ Dependencies retrofit2ConverterSimpleXML this dependencies ```

jrgonzalez · Answer

but I am only guessing there and it is type unsafe as soon as you add groovy in

jrgonzalez · Answer

The global exclude is also a bit tricky may work for this one but on others I am excluding for different reasons not all versions of a module but only those coming transitively on a specific dependency due to conflicts The duplicated config section may be better for now to not have several different ways to do the same

jrgonzalez · Answer

Also luckily I don t have many that need configuration

jrgonzalez · Answer

and it even seems some of those issues are fixed since last time I checked so maybe I can remove a few more customizations

jrgonzalez · Answer

Thanks for all your help 1am here time to sleep smile

gildor · Answer

You don t need groovy builder for this I will check later today

gildor · Answer

I agree global exclude may be not so straight forward but usually it s more stable and clean solution To solve version conflict you also can use global configuration resolution I would still take a look on this solution

jrgonzalez · Answer

Also there is another type of configuration I have on some dependencies that require `isTransitive = true` which I am not sure if it has a global way

gildor · Answer

Why is your use case for isTransitive = true This is default behavior of any dependency

jrgonzalez · Answer

It fails without it on an old Twitter dependency I have not had time to remove since they discontinued it I will post when I m back at home in a bit I have no idea why it fails without the `isTransitive` either

jrgonzalez · Answer

I have also seen instructions for several libs that say to include it like that so there may be some differences Others like glide had it and then seemingly removed the requirement but I m not sure what changed

gildor · Answer

Could you show this dependency

jrgonzalez · Answer

This is it on normal syntax ``` implementation com twitter sdk android tweet composer 3 3 0 aar isTransitive = true ```

jrgonzalez · Answer

without the isTransitive my build fails with unknown `com twitter sdk android core` package

gildor · Answer

Just remove `< aar>` and isTransitive

gildor · Answer

Those guys from Twitter don t know how to use dependencies probably Because explicit declaration of resources extension obviously disables transitive dependencies because you cannot get transitive dependencies without pom file

jrgonzalez · Answer

Oh ok so maybe the others I have with ` aar` also should get rid of it I thought it was something to distinguish aar vs jar or something like that

jrgonzalez · Answer

seems to compile now with just `implementation Dependencies twitterSdkTweetComposer ` tada

gildor · Answer

+1

gildor · Answer

Really not sure how they decided to use such config maybe some super old legacy when they don t have pom only raw aar Funny that Crashlytics used the same strange config in their docs when they owned by Twitter now Google acquired them and this thing moved also to Firebase docs for Crashlytics grimacing