Calling `.value` on a SettingKey doesn't trigger any execution and
doesn't have any side effect, so we can safely allow calls to `.value`
inside conditionals and lambdas.
Fixes#3299
This undeprecates the syntax, but at the same times moves it out of
implicit scope, therefore requiring a 'import TupleSyntax._' to opt-in
to the old syntax.
Before, we were not preserving the value `insideXXX`. This commit makes
sure that we handle much more complex scenarios and we report them
successfully. Have a look at the tests.
The missing .value analysis is dumb on purpose because it's expensive.
Detecting valid use cases of idents whose type is an sbt key is
difficult and dangerous because we may miss some corner cases. Instead,
we report on the easiest cases in which we are certain that the user
does not want to have a stale key reference. Those are idents in the rhs
of val definitions with `_` as name and idents in statement position
inside blocks.
In the future, we can cover all val definitions no matter what their
name is. Unfortunately, doing so will come at the cost of speed: we have
to run the unused name analysis in `TypeDiagnostics` and expose it from
the power context in `ContextUtil`.
This is good enough for now. If users express interest in having a
smarter analysis, we can always consider trying the unused name
analysis. I am not sure how slow it will be -- hopefully it won't be
that much.
This commit does the following things:
* Removes the boolean from the instance context passes to the linter.
* Prohibits the use of value inside anonymous functions.
* Improves the previous check of `value` inside if.
The improvements have occurred thanks to the fix of an oversight in the
traverser. As a result, several implementation of tasks have been
rewritten because of new compilation failures by both checks.
Note that the new check that prohibits the use of value inside anonymous
functions ignores all the functions whose parameters have been
synthesized by scalac (that can happen in a number of different
scenarios, like for comprehensions). Other scripted tests have also been
fixed.
Running `.value` inside an anonymous function yields the following
error:
```
[error] /data/rw/code/scala/sbt/main-settings/src/test/scala/sbt/std/TaskPosSpec.scala:50:24: The evaluation of `foo` inside an anonymous function is prohibited.
[error]
[error] Problem: Task invocations inside anonymous functions are evaluated independently of whether the anonymous function is invoked or not.
[error]
[error] Solution:
[error] 1. Make `foo` evaluation explicit outside of the function body if you don't care about its evaluation.
[error] 2. Use a dynamic task to evaluate `foo` and pass that value as a parameter to an anonymous function.
[error]
[error] val anon = () => foo.value + " "
[error] ^
```
`.value` inside the if of a regular task is unsafe. The wrapping task
will always execute the value, no matter what the if predicate yields.
This commit adds the infrastructure to lint code for every sbt DSL
macro. It also adds example of neg tests that check that the DSL checks
are in place.
The sbt checks yield error for this specific case because we may want to
explore changing this behaviour in the future. The solutions to this are
straightforward and explained in the error message, that looks like
this:
```
EXPECTED: The evaluation of `fooNeg` happens always inside a regular task.
PROBLEM: `fooNeg` is inside the if expression of a regular task.
Regular tasks always evaluate task inside the bodies of if expressions.
SOLUTION:
1. If you only want to evaluate it when the if predicate is true, use a dynamic task.
2. Otherwise, make the static evaluation explicit by evaluating `fooNeg` outside the if expression.
```
Aside from those solutions, this commit also adds a way to disable any
DSL check by using the new `sbt.unchecked` annotation. This annotation,
similar to `scala.annotation.unchecked` disables compiler output. In our
case, it will disable any task dsl check, making it silent.
Examples of positive checks have also been added.
There have been only two places in `Defaults.scala` where this check has
made compilation fail.
The first one is inside `allDependencies`. To ensure that we still have
static dependencies for `allDependencies`, I have hoisted up the value
invocation outside the if expression. We may want to explore adding a
dynamic task in the future, though. We are doing unnecessary work there.
The second one is inside `update` and is not important because it's not
exposed to the user. We use a `taskDyn`.
This commit adds the first version of the checker that will tell users
if they are doing something wrong.
The first version warns any user that write `.value` inside an if
expression.
As the test integration is not yet working correctly and messages are
swallowed, we have to println to get info from the test.
Fixes#3178
While working on the Scopes and Scope Delegation document, I noticed that the term Global in sbt is used for two different meaning.
1. Universal fallback scope component `*`
2. An alias for GlobalScope
This disambiguates the two by renaming ScopeAxis instance to Zero.
Since this is mostly internal to sbt code, the impact to the user should be minimal.
This fixes the following error when trying to use inputTaskDyn in a build:
[error] /tmp/sbt_8316130f/input-task-dyn/build.sbt:11: error: Macro
expansion contains free type variable T defined by wrap in
InputConvert.scala:76:20. Have you forgotten to use c.WeakTypeTag
annotation for this type parameter? If you
have troubles tracking free type variables, consider using -Xlog-free-types (out-1)
[error] runFoo := Def.inputTaskDyn { (out-1)
[error] ^ (out-1)
[info] [error] sbt.compiler.EvalException: Type error in expression (out-3) (out-1)
I have no idea what the error means, I just implemented the suggested fix.
This adds a macro-level hack to support += op for sourceGenerators and resourceGenerators using RHS of Initialize[Task[Seq[File]]].
When the types match up, the macro now calls `.taskValue` automatically.
Dale Wijnand
eugene yokota
Martin Duhem
jvican
Guillaume Martres
Josh Soref