Provider.map is incompatible with excluded tasks

[ejona86]

Expected Behavior

Calling get() on a provider created with provider.map { it } succeeds in a task action, even if the task that produced the original provider is excluded.

Dealing with excluded tasks (-x) in a build is strange and might be open to interpretation on precise behavior, but it seems it should behave similarly to a disabled task (enable = false) and definitely not penalize .map{} usage. If the current behavior is working as designed then modern providers are incompatible with task exclusion and exclusion should be deprecated to allow using provider.map in plugins.

Current Behavior

Within a task action, calling provider.get() for output of an excluded task commonly works. But if the provider was mapped (provider.map { it }.get()) then the build fails:

Querying the mapped value of provider(interface java.util.Set) before task ':excludedTask' has completed is not supported

Context

A user complained about a bug in my plugin after the plugin introduced a .map {} usage. (It is unclear what caused the issue for the original poster, but that later user did provide a clear repro which I used to investigate.)

Steps to Reproduce

https://github.com/ejona86/gradle-bug-map-exclude

$ ./gradlew build --continue

> Task :brokenWithMapInActionWhenTaskExcluded FAILED
[/tmp/gradle-exclude-mapped/build/created1]

> Task :brokenWithMapWhenTaskExcluded FAILED
Execution optimizations have been disabled for task ':brokenWithMapWhenTaskExcluded' to ensure correctness due to the following reasons:
  - Type 'ProcessInput' property 'inputArg' cannot be resolved:  Querying the mapped value of provider(interface java.util.Set) before task ':excludedTask' has completed is not supported. Reason: An input file collection couldn't be resolved, making it impossible to determine task inputs. Please refer to https://docs.gradle.org/7.4.2/userguide/validation_problems.html#unresolvable_input for more details about this problem.

> Task :workingWithMapWhenTaskDisabled
[/tmp/gradle-exclude-mapped/build/created3]

> Task :workingWithMapWhenTaskNormal
[/tmp/gradle-exclude-mapped/build/created2]

> Task :workingWithoutMapWhenTaskExcluded
[/tmp/gradle-exclude-mapped/build/created1]

FAILURE: Build completed with 2 failures.

1: Task failed with an exception.
-----------
* Where:
Build file '/tmp/gradle-exclude-mapped/build.gradle' line: 34

* What went wrong:
Execution failed for task ':brokenWithMapInActionWhenTaskExcluded'.
> Querying the mapped value of provider(interface java.util.Set) before task ':excludedTask' has completed is not supported

* Try:
> Run with --stacktrace option to get the stack trace.
> Run with --info or --debug option to get more log output.
> Run with --scan to get full insights.
==============================================================================

2: Task failed with an exception.
-----------
* Where:
Build file '/tmp/gradle-exclude-mapped/build.gradle' line: 7

* What went wrong:
Execution failed for task ':brokenWithMapWhenTaskExcluded'.
> Querying the mapped value of provider(interface java.util.Set) before task ':excludedTask' has completed is not supported

* Try:
> Run with --stacktrace option to get the stack trace.
> Run with --info or --debug option to get more log output.
> Run with --scan to get full insights.
==============================================================================

Your Environment

Build scan URL: https://gradle.com/s/tpslxaztlxvma

[stmlange]

Bumped into this issue as well and find it very frustrating. Any plans to triage this soonish and perhaps even get it fixed?

[stmlange]

Any updates on this?