tree 792976082a6097b3050190c6cf9a781a08b85d44
parent 0f93a6b966dc034e028d9a1cc9fc880f66b803d6
author Googler <brandjon@google.com> 1713454047 -0700
committer Copybara-Service <copybara-worker@google.com> 1713454292 -0700

Allow macros to have attributes

This adds an `attrs` param to the `macro()` callable, allowing users to specify an attribute schema for symbolic macros. As for rules, the `name` attribute is implied and should not be included in `attrs`, while certain other names are reserved and can never be defined on macros. Macros support default values and implicit defaults, but not computed defaults or late-bound defaults.

StarlarkRuleClassFunctions.java
- Add attr schema validation to `macro()`.
- Factor instantiation logic from `MacroFunction#call()` to `MacroClass#instantiateAndAddMacro()`.
- Replace ad hoc `name` attr validation with standard RuleClass#NAME_ATTRIBUTE logic.

BuildType.java
- In `copyAndLiftStarlarkValue`, generalize `ruleClass` param to apply to macros as well, and update stringification in `AttributeConversionContext` accordingly.

MacroClass.java
- Add significant new logic to instantiate a macro by processing and validating its attribute values.

BazelEvaluationTestCase.java
- Add ability to inject config fragments into the Starlark environment. Used by one new test case that can't take advantage of `BuildViewTestCase`'s existing fragment setup.

New test cases are added to StarlarkRuleClassFunctionsTest.java and SymbolicMacroTest.java, with the loose rationale that the former is for cases that don't require an implementation function to run and the latter is for everything else. But it may be more sensible to just move all the symbolic macro tests to the latter file in the future.

Work toward #19922.

PiperOrigin-RevId: 626042528
Change-Id: Ie1c09cfdf2ca2168467035b2fa0ccd75cbf68dfd