bxl aquery: allow passing in bxl.Action

This allows for fine grained action graph debugging by letting bxl ask
about individual Actions' dependencies.

I chose this API because it's the smallest API surface change I could
think of to improve this.

One thing which Claude pointed out is that you can't have heterogeneous
lists of Actions and aquery nodes. This is sorta unfortunate.

Allows users to implement "What deps does my action have recorded for
it" from #1217 themselves.

Note that I tried running the tests I could using buck bxl but
I have not gone to https://metacareers.com to be able to run the python
side.

Example usage:
Use `ctx.audit.output()` to obtain an Action object and then ask about
its dependencies.

Author: lf-

app/buck2_build_api/src/query/bxl.rs

@@ -12,6 +12,7 @@ use std::future::Future;
 use std::pin::Pin;
 
 use async_trait::async_trait;
+use buck2_artifact::actions::key::ActionKey;
 use buck2_core::cells::CellResolver;
 use buck2_core::cells::name::CellName;
 use buck2_core::configuration::compatibility::MaybeCompatible;
@@ -183,6 +184,11 @@ pub trait BxlAqueryFunctions: Send {
         dice: &mut DiceComputations<'_>,
         targets: &TargetSet<ActionQueryNode>,
     ) -> buck2_error::Result<TargetSet<ActionQueryNode>>;
+    async fn get_action_nodes(
+        &self,
+        dice: &mut DiceComputations<'_>,
+        action_keys: Vec<ActionKey>,
+    ) -> buck2_error::Result<TargetSet<ActionQueryNode>>;
 }
 
 pub static NEW_BXL_CQUERY_FUNCTIONS: LateBinding<

app/buck2_bxl/src/bxl/starlark_defs/aquery.rs

@@ -9,6 +9,7 @@
  */
 
 use allocative::Allocative;
+use buck2_artifact::actions::key::ActionKey;
 use buck2_build_api::actions::query::ActionQueryNode;
 use buck2_build_api::query::bxl::BxlAqueryFunctions;
 use buck2_build_api::query::bxl::NEW_BXL_AQUERY_FUNCTIONS;
@@ -46,6 +47,7 @@ use starlark::values::type_repr::StarlarkTypeRepr;
 
 use crate::bxl::starlark_defs::context::BxlContext;
 use crate::bxl::starlark_defs::context::ErrorPrinter;
+use crate::bxl::starlark_defs::nodes::action::StarlarkAction;
 use crate::bxl::starlark_defs::nodes::action::StarlarkActionQueryNode;
 use crate::bxl::starlark_defs::providers_expr::AnyProvidersExprArg;
 use crate::bxl::starlark_defs::providers_expr::ProvidersExpr;
@@ -122,6 +124,7 @@ enum UnpackActionNodes<'v> {
     ActionQueryNodesSet(&'v StarlarkTargetSet<ActionQueryNode>),
     ConfiguredProviders(AnyProvidersExprArg<'v>),
     ConfiguredTargets(ConfiguredTargetListExprArg<'v>),
+    StarlarkActions(UnpackList<StarlarkAction>),
 }
 
 // Aquery operates on `ActionQueryNode`s. Under the hood, the target set of action query nodes is obtained
@@ -140,6 +143,14 @@ async fn unpack_action_nodes<'v>(
             return Ok(action_nodes.into_iter().map(|v| v.0).collect());
         }
         UnpackActionNodes::ActionQueryNodesSet(action_nodes) => return Ok(action_nodes.0.clone()),
+        UnpackActionNodes::StarlarkActions(actions) => {
+            let action_keys: Vec<ActionKey> = actions
+                .into_iter()
+                .map(|starlark_action| starlark_action.0.key().dupe())
+                .collect();
+
+            return aquery_env.get_action_nodes(dice, action_keys).await;
+        }
         UnpackActionNodes::ConfiguredProviders(arg) => {
             ProvidersExpr::<ConfiguredProvidersLabel>::unpack(
                 arg,
@@ -183,6 +194,11 @@ async fn unpack_action_nodes<'v>(
 ///
 /// Query results are `target_set`s of `action_query_node`s, which supports iteration,
 /// indexing, `len()`, set addition/subtraction, and `equals()`.
+///
+/// Actions can be specified as:
+/// - Target expressions (configured targets/providers)
+/// - Existing action query nodes or target sets
+/// - `bxl.Action` objects (obtained from `ctx.audit().output()`)
 #[starlark_module]
 fn aquery_methods(builder: &mut MethodsBuilder) {
     /// The deps query for finding the transitive closure of dependencies.

app/buck2_query_impls/src/aquery/bxl.rs

@@ -12,6 +12,7 @@ use std::marker::PhantomData;
 use std::sync::Arc;
 
 use async_trait::async_trait;
+use buck2_artifact::actions::key::ActionKey;
 use buck2_build_api::actions::query::ActionQueryNode;
 use buck2_build_api::analysis::calculation::RuleAnalysisCalculation;
 use buck2_build_api::query::bxl::BxlAqueryFunctions;
@@ -303,6 +304,24 @@ impl BxlAqueryFunctions for BxlAqueryFunctionsImpl {
         })
         .await
     }
+
+    async fn get_action_nodes(
+        &self,
+        dice: &mut DiceComputations<'_>,
+        action_keys: Vec<ActionKey>,
+    ) -> buck2_error::Result<TargetSet<ActionQueryNode>> {
+        dice.with_linear_recompute(|dice| async move {
+            let delegate = self.aquery_delegate(&dice).await?;
+            let mut result = TargetSet::new();
+            let nodes = buck2_util::future::try_join_all(
+                action_keys.iter().map(|key| delegate.get_action_node(&key)),
+            )
+            .await?;
+            result.extend(nodes);
+            Ok(result)
+        })
+        .await
+    }
 }
 
 pub(crate) fn init_new_bxl_aquery_functions() {

tests/core/query/aquery/test_aquery.py

@@ -154,3 +154,16 @@ async def test_bxl_aquery_eval(buck: Buck) -> None:
 @buck_test()
 async def test_bxl_aquery_action_query_node(buck: Buck) -> None:
     await buck.bxl("//:aquery.bxl:action_query_node")
+
+
+# Tests for bxl.Action support in aquery operations
+@buck_test()
+async def test_bxl_action_deps_0(buck: Buck) -> None:
+    """Test passing a bxl.Action to aquery.deps() with depth=0 returns itself"""
+    await buck.bxl("//:aquery.bxl:action_deps_0")
+
+
+@buck_test()
+async def test_bxl_action_deps(buck: Buck) -> None:
+    """Test that you can isolate the deps of one action by itself"""
+    await buck.bxl("//:aquery.bxl:action_deps")

tests/core/query/aquery/test_aquery_data/aquery.bxl

@@ -141,3 +141,38 @@ action_query_node = bxl_main(
     impl = _impl_action_query_node,
     cli_args = {},
 )
+
+def _impl_action_deps_0(ctx):
+    """Test passing a bxl.Action to aquery.deps() returns itself"""
+    nodes = ctx.aquery().eval("//:test")
+
+    action = nodes[0].action()
+
+    # Pass the bxl.Action rather than a target to aquery.deps()
+    result = ctx.aquery().deps([action], depth = 0)
+    _assert_eq(action.outputs(), result[0].action().outputs())
+
+action_deps_0 = bxl_main(
+    impl = _impl_action_deps_0,
+    cli_args = {},
+)
+
+def _impl_action_deps(ctx):
+    """Test that you can isolate the deps of one action by itself"""
+    nodes = ctx.aquery().eval("//:test")
+
+    action = nodes[0].action()
+
+    # Pass the bxl.Action rather than a target to aquery.deps()
+    result = ctx.aquery().deps([action], depth = 1)
+
+    _assert_eq(len(result), 2)
+    # First should be itself
+    _assert_eq(action.outputs(), result[0].action().outputs())
+    dep = result[1]
+    _assert_eq(dep.action().outputs()[0].short_path, "dep")
+
+action_deps = bxl_main(
+    impl = _impl_action_deps,
+    cli_args = {},
+)

tests/core/query/aquery/test_aquery_data/prelude.bzl

@@ -9,6 +9,7 @@
 def _test(ctx: AnalysisContext):
     dep = ctx.actions.write("dep", "")
     default = ctx.actions.copy_file("default", dep)
+    other_default = ctx.actions.copy_file("other_default", dep)
     other = ctx.actions.write("other", "")
 
     sub_default = ctx.actions.write("sub_default", "")
@@ -18,7 +19,7 @@ def _test(ctx: AnalysisContext):
     ctx.actions.write("unused", "")
 
     return [DefaultInfo(
-        default_outputs = [default],
+        default_outputs = [default, other_default],
         other_outputs = [other],
         sub_targets = {
             "sub": [