Evaluate if T.command overload accepting a Task can be removed
#3517
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|
I'd like to remove the overload |
lefou
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Sep 12, 2024
lefou
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Sep 12, 2024
`T.command` currently has two overloads, one accepting a `Result` (like
most of the other task factories, `T`, `T.input`, `T.task` and so on)
and one accepting a `Task`. Because of the second version, command
definitions like the following don't do what the user thinks they do,
although they seem to work.
```scala
override def publishLocal(localIvyRepo: String): Command[Unit] = T.command {
super.publishLocal(localIvyRepo)
}
```
Instead of creating a new command that depends on another command (the
`super`-version) and returns just the result, it returns the
`super`-command as-is.
The correct version is:
```scala
override def publishLocal(localIvyRepo: String): Command[Unit] = T.command {
super.publishLocal(localIvyRepo)()
}
```
```diff
override def publishLocal(localIvyRepo: String): Command[Unit] = T.command {
- super.publishLocal(localIvyRepo)
+ super.publishLocal(localIvyRepo)()
}
```
This change deprecates all overloads accepting a `Task` in favor of
accepting a `Result`. `Result`s can be easily acquired from a `Task` by
calling `apply()` or short `()`.
This is also the more correct way of re-using or re-defining tasks,
since directly re-used tasks may result in an incorrect tasks context,
esp. an incorrect source location, which is relevant when debugging
misbehaving builds.
See #3517
Pull request: #3524
|
As a first step, I deprecated all Target creators which accept a |
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Forgotten parenthesis on commands are a frequent cause of issue.
Here is the latest encouter:
T.commandcurrently has two overloads, one accepting aResult(like most of the other task factories,T,T.input,T.taskand so on) and one accepting aTask. Because of the second version, command definitions like the following don't do what the user thinks they do, although they seem to work.Instead of creating a new command, that depends on another command (the
super-version) and returns just the result, it returns thesuper-command as-is.The correct version is:
override def publishLocal(localIvyRepo: String): Command[Unit] = T.command { - super.publishLocal(localIvyRepo) + super.publishLocal(localIvyRepo)() }I wonder why we have this overload and if we should just remove it, since it causes a lot of issues. It was one of my first issues I had myself when I experimented with Mill IIRC and I helped others to identify it many many times. The rule of thumb since then is, to always use one extra pair of parenthesis compared to the definition side of the task you want to call.
This is quite obviously an issue with our API which we should fix.
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