Why do I need to reference a custom gradle config with square brackets? - kotlin

Question

I created a gradle build config just to download some dependencies. The documentation has been sparse, so I've piece together this working snippet based on random snippets and guesses.
configurations {
create("downloadDeps")
}
dependencies {
// JSON
configurations["downloadDeps"]("com.fasterxml.jackson.core:jackson-databind:2.13.3")
configurations["downloadDeps"]("com.fasterxml.jackson.module:jackson-module-kotlin:2.13.3")
}
repositories {
// internal repository
maven {
url = uri("...")
credentials {
username = System.getenv("ARTIFACTORY_USER") ?: System.getProperty("ARTIFACTORY_USER") as String
password = System.getenv("ARTIFACTORY_TOKEN") ?: System.getProperty("ARTIFACTORY_TOKEN") as String
}
}
}
tasks.register<Copy> ("downloadDeps") {
from(configurations["downloadDeps"])
into("lib/")
}
If I reference the "downloadDeps" dependency like configuration.downloadDeps or downloadDeps("com.fasterxml.jackson.core:jackson-databind:2.13.3"). I get an error about an unresolved reference to "downloadDeps".
Why does implementation("...") or configuration.implementation.get() work?

Answer 1

The documentation #Slaw provided helped me understand why I can do something like this:
implementation("group:artifact:1.0.0")
but not
myCustomConfig("group:artifact:1.0.0")
implementation being declared that way is supported because it comes from a plugin (the Kotlin/Java plugins)
The simplest way to associate a dependency with myCustomConfig would be to do this (see these docs):
"myCustomConfig"("group:artifact:1.0.0")