Move the remaining aggregate functions into vortex-aggregates

vortex-array now keeps only the aggregate function framework and
`all_non_distinct`, which `assert_arrays_eq!` uses to compare arrays. The
other concrete aggregates (min/max, sum, counts, sortedness, constancy,
uncompressed size and the rest), their Dict kernels, the grouped encoding
kernels and their benches move to vortex-aggregates, whose `initialize`
registers them on a session. `Stat::aggregate_fn` is replaced by
`vortex_aggregates::stat_aggregate_fn`.

`ExtensionStoragePushdown` stays in vortex-array. Pushing `is_sorted` and
`min_max` down into extension storage becomes
`vortex_aggregates::register_storage_ordered`, which `initialize` calls for the
temporal types and `vortex_uuid::initialize` calls for UUIDs.

Validation and encoding paths that must work with any session no longer go
through the registry: integer arrays use `integer_bounds` (which now also
reports strict sortedness and caches Min, Max and NullCount), and boolean
arrays use the new `bool_bounds`. This covers validity, RunEnd ends,
bit-packing, FoR, datetime-parts comparison and the compressor's integer
statistics.

Tests of aggregate behaviour move alongside the aggregates. Core tests use a
test-only row-count aggregate and run the aggregate consistency checks only
when aggregates are registered. Test
sessions that compute statistics register the aggregates.

Signed-off-by: Claude <noreply@anthropic.com>
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Ps4mp7KF5c4p66aoSoXx5j
Signed-off-by: Claude <noreply@anthropic.com>

Author: claude

Cargo.lock

@@ -33,8 +33,8 @@ use parquet::arrow::ParquetRecordBatchStreamBuilder;
 use parquet::arrow::ProjectionMask;
 use tokio::fs::File;
 use vortex::VortexSessionDefault;
-use vortex::aggregate_fn::fns::uncompressed_size_in_bytes::UncompressedSizeOpts;
-use vortex::aggregate_fn::fns::uncompressed_size_in_bytes::uncompressed_size_in_bytes;
+use vortex::aggregates::uncompressed_size_in_bytes::UncompressedSizeOpts;
+use vortex::aggregates::uncompressed_size_in_bytes::uncompressed_size_in_bytes;
 use vortex::array::ArrayRef;
 use vortex::array::ExecutionCtx;
 use vortex::array::IntoArray;

benchmarks/string-bench/src/lib.rs

@@ -20,6 +20,7 @@ alp = { workspace = true }
 itertools = { workspace = true }
 num-traits = { workspace = true }
 prost = { workspace = true }
+vortex-aggregates = { workspace = true }
 vortex-array = { workspace = true }
 vortex-buffer = { workspace = true }
 vortex-error = { workspace = true }

encodings/alp/Cargo.toml

@@ -1,11 +1,11 @@
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-FileCopyrightText: Copyright the Vortex contributors
 
+use vortex_aggregates::nan_count::NanCount;
+use vortex_aggregates::nan_count::nan_count;
 use vortex_array::ArrayRef;
 use vortex_array::ExecutionCtx;
 use vortex_array::aggregate_fn::AggregateFnRef;
-use vortex_array::aggregate_fn::fns::nan_count::NanCount;
-use vortex_array::aggregate_fn::fns::nan_count::nan_count;
 use vortex_array::aggregate_fn::kernels::DynAggregateKernel;
 use vortex_array::scalar::Scalar;
 use vortex_error::VortexResult;

encodings/alp/src/alp/compute/nan_count.rs

@@ -16,9 +16,9 @@
 //!
 //! [paper]: https://ir.cwi.nl/pub/33334/33334.pdf
 
+use vortex_aggregates::nan_count::NanCount;
 use vortex_array::ArrayVTable;
 use vortex_array::aggregate_fn::AggregateFnVTable;
-use vortex_array::aggregate_fn::fns::nan_count::NanCount;
 use vortex_array::aggregate_fn::session::AggregateFnSessionExt;
 use vortex_array::arrays::patched::use_experimental_patches;
 use vortex_array::session::ArraySessionExt;

encodings/alp/src/lib.rs

@@ -18,6 +18,7 @@ workspace = true
 [dependencies]
 num-traits = { workspace = true }
 prost = { workspace = true }
+vortex-aggregates = { workspace = true }
 vortex-array = { workspace = true }
 vortex-buffer = { workspace = true }
 vortex-compute = { workspace = true }

encodings/datetime-parts/Cargo.toml

@@ -288,10 +288,10 @@ mod test {
     use std::sync::LazyLock;
 
     use rstest::rstest;
+    use vortex_aggregates::sum::sum;
     use vortex_array::ArrayRef;
     use vortex_array::ExecutionCtx;
     use vortex_array::VortexSessionExecute;
-    use vortex_array::aggregate_fn::fns::sum::sum;
     use vortex_array::arrays::BoolArray;
     use vortex_array::arrays::ConstantArray;
     use vortex_array::arrays::PrimitiveArray;

encodings/datetime-parts/src/compute/compare.rs

@@ -1,11 +1,11 @@
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-FileCopyrightText: Copyright the Vortex contributors
 
+use vortex_aggregates::is_constant::IsConstant;
+use vortex_aggregates::is_constant::is_constant;
 use vortex_array::ArrayRef;
 use vortex_array::ExecutionCtx;
 use vortex_array::aggregate_fn::AggregateFnRef;
-use vortex_array::aggregate_fn::fns::is_constant::IsConstant;
-use vortex_array::aggregate_fn::fns::is_constant::is_constant;
 use vortex_array::aggregate_fn::kernels::DynAggregateKernel;
 use vortex_array::scalar::Scalar;
 use vortex_error::VortexResult;

encodings/datetime-parts/src/compute/is_constant.rs

@@ -11,9 +11,9 @@ mod compute;
 mod ops;
 mod timestamp;
 
+use vortex_aggregates::is_constant::IsConstant;
 use vortex_array::ArrayVTable;
 use vortex_array::aggregate_fn::AggregateFnVTable;
-use vortex_array::aggregate_fn::fns::is_constant::IsConstant;
 use vortex_array::aggregate_fn::session::AggregateFnSessionExt;
 use vortex_array::session::ArraySessionExt;
 use vortex_session::VortexSession;

encodings/datetime-parts/src/lib.rs

@@ -18,6 +18,7 @@ workspace = true
 [dependencies]
 num-traits = { workspace = true }
 prost = { workspace = true }
+vortex-aggregates = { workspace = true }
 vortex-array = { workspace = true }
 vortex-buffer = { workspace = true }
 vortex-error = { workspace = true }