BE-587, BE-588: HashQL: Introduce CodeGenerationContext/CodeExecutionContext split and eval-stage Interner

[indietyp]

🌟 What is the purpose of this PR?

This PR refactors the HashQL evaluation pipeline to introduce a cleaner separation between the code generation phase and the code execution phase. The previously unified EvalContext is split into CodeGenerationContext (used during MIR compilation and Postgres query preparation) and CodeExecutionContext (used during orchestrated query execution). This makes the data flow and lifecycle of each phase explicit and prevents accidental misuse of context across phase boundaries.

Additionally, a dedicated eval::intern::Interner is introduced for the evaluation stage, which must be constructed from the MIR interner via From to preserve interned pointer identity across the MIR/eval boundary. Input construction for orchestrator tests is also migrated away from using the JSON decoder to directly building typed Value trees using the heap allocator, removing a dependency on the type environment at input-construction time.

The compile_query implementation in the graph API is stubbed out with unimplemented! pending the HashQL API wire-up tracked in BE-537.

🔗 Related links

• BE-537: HashQL — Remove old backend wire-up, wire up HashQL in the API (internal)

🔍 What does this change?

• Renames EvalContext to CodeGenerationContext and introduces a new CodeExecutionContext struct that is produced from CodeGenerationContext via From, carrying only the fields needed at execution time.
• Adds eval::intern::Interner as a dedicated interner for the evaluation stage, constructed from hashql_mir::intern::Interner to preserve pointer identity.
• Updates Orchestrator and PostgresCompiler to use the appropriate context type for their respective phases.
• Replaces JSON-decoder-based input construction in orchestrator tests with direct Value tree construction using heap-allocated Rc and StructBuilder, removing the dependency on the post-lowering type environment for building inputs.
• Stubs out EntityQuery::compile_query with unimplemented! and suppresses dead_code warnings pending the full HashQL API integration.
• Updates the EvalDiagnosticCategory enum to replace the graph-feature-gated Graph variant with an Orchestrator variant backed by OrchestratorDiagnosticCategory.
• Migrates orchestrator test helpers to pass Lowered by value (consuming it) and convert the MIR interner into the eval interner at the appropriate pipeline stage.

🛡 What tests cover this?

• Existing orchestrator integration tests and eval_postgres compile tests exercise the refactored context types and input construction.
• Decoder unit tests updated to use Interner::testing for the new eval-stage interner.

❓ How to test this?

1. Run cargo test across the hashql-eval and hash-graph-api crates.
2. Run the orchestrator integration tests to confirm query execution still produces correct results against a live Postgres instance.

[cursor]

PR Summary

Medium Risk
Entity/subgraph requests with a raw query field now fail with 501 instead of compiling HashQL; eval/orchestrator and Postgres compile paths are refactored but covered by existing tests.

Overview
Splits HashQL eval into code generation vs execution contexts: EvalContext becomes CodeGenerationContext (Postgres compilation, live-out, diagnostics) and a slimmer CodeExecutionContext used by Orchestrator after From conversion.

Adds hashql_eval::intern::Interner, created from the MIR interner so symbol interning stays consistent across the MIR→eval boundary; orchestrator codec/partial paths and tests use it instead of hashql_mir::intern::Interner.

Graph API: removes the full in-request HashQL compile pipeline for EntityQuery::Query; those requests now return HTTP 501 with a BE-537 link until HashQL is wired in the API. Filter-based queries are unchanged.

Orchestrator tests build interpreter Inputs as heap-backed opaque/struct Value trees (no JSON Decoder / type env at input construction). Execution helpers consume Lowered by value, convert MIR→eval interner before compile, then run via run_in with the heap allocator.

EvalDiagnosticCategory drops the graph compiler variant in favor of Orchestrator for eval diagnostics.

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[indietyp]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• BE-537: hgraph: REST /hashql endpoint with E2E tests #8827
• BE-592: HashQL: Remove old eval graph path and core value types #8841
• BE-590: hgraph: Refactor entity query handlers into entity/query submodule #8840
• BE-587, BE-588: HashQL: Introduce CodeGenerationContext/CodeExecutionContext split and eval-stage Interner #8839 👈 (View in Graphite)
• BE-581, BE-589: HashQL: Introduce pass::lower/pass::place pipeline facades and fix cached constructor closure bug #8838
• BE-585, BE-591: HashQL: Add MIR interpreter test suite and refactor diagnostic categories #8837
• BE-583, BE-584, BE-586: HashQL: Add HeapPool, improve spans, and propagate Critical severity through diagnostics #8836
• BE-582: HashQL: Change opaque types from invariant to covariant #8835
• main

This stack of pull requests is managed by Graphite. Learn more about stacking.

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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[codecov]

Codecov Report

❌ Patch coverage is 60.52632% with 15 lines in your changes missing coverage. Please review.
✅ Project coverage is 59.55%. Comparing base (b939729) to head (3d05f60).

Files with missing lines	Patch %	Lines
libs/@local/hashql/eval/src/context.rs	52.94%	8 Missing ⚠️
.../@local/graph/api/src/rest/entity_query_request.rs	0.00%	4 Missing ⚠️
libs/@local/hashql/core/src/graph/linked.rs	0.00%	2 Missing ⚠️
libs/@local/hashql/eval/src/error.rs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@                                          Coverage Diff                                           @@
##           bm/be-581-hashql-cached-constructor-produces-bare-fnptr-instead-of    #8839      +/-   ##
======================================================================================================
+ Coverage                                                               59.53%   59.55%   +0.02%     
======================================================================================================
  Files                                                                    1347     1348       +1     
  Lines                                                                  130960   130870      -90     
  Branches                                                                 5884     5884              
======================================================================================================
- Hits                                                                    77961    77942      -19     
+ Misses                                                                  52092    52021      -71     
  Partials                                                                  907      907              

Flag	Coverage Δ
apps.hash-ai-worker-ts	1.39% <ø> (ø)
apps.hash-api	0.00% <ø> (ø)
local.hash-backend-utils	2.81% <ø> (ø)
local.hash-graph-sdk	9.63% <ø> (ø)
local.hash-isomorphic-utils	0.00% <ø> (ø)
rust.hash-graph-api	2.56% <0.00%> (+0.04%)	⬆️
rust.hashql-compiletest	28.41% <ø> (ø)
rust.hashql-eval	74.94% <71.87%> (-0.27%)	⬇️
rust.hashql-hir	89.06% <ø> (ø)

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[Copilot]

Pull request overview

Refactors the HashQL evaluation pipeline to explicitly separate code-generation vs code-execution concerns by splitting the former EvalContext into CodeGenerationContext and CodeExecutionContext, and introduces an eval-stage intern::Interner to preserve interned pointer identity across the MIR → eval boundary. Test harnesses and orchestrator utilities are updated to construct typed Value inputs directly (without the JSON decoder/type-env dependency) and to pass the appropriate context/interner types through the compilation/execution stages.

Changes:

• Split evaluation context into generation/execution contexts and updated Postgres compilation + orchestrator execution call sites accordingly.
• Added eval-stage intern::Interner (convertible from MIR interner) and migrated decoder/tests to use it.
• Reworked orchestrator test input construction to build heap-allocated typed Value trees directly; graph API compile_query was stubbed pending BE-537.

Reviewed changes

Copilot reviewed 21 out of 21 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
libs/@local/hashql/eval/tests/orchestrator/output.rs	Generalized success rendering to support non-Global value allocators.
libs/@local/hashql/eval/tests/orchestrator/main.rs	Updated test driver to consume lowered artifacts and pass symbol intern sets into input builder.
libs/@local/hashql/eval/tests/orchestrator/inputs.rs	Replaced JSON-decoder-based input construction with direct typed Value construction using heap allocation + struct builders.
libs/@local/hashql/eval/tests/orchestrator/execution.rs	Updated lowering/execution glue to use MIR interner → eval interner conversion and the new context split; switched to Orchestrator::run_in.
libs/@local/hashql/eval/src/postgres/projections.rs	Added #[inline] on a conversion impl.
libs/@local/hashql/eval/src/postgres/parameters.rs	Added #[inline] on a conversion impl.
libs/@local/hashql/eval/src/postgres/mod.rs	Switched compiler context type to CodeGenerationContext and updated docs accordingly.
libs/@local/hashql/eval/src/postgres/filter/tests.rs	Migrated tests to CodeGenerationContext and eval-stage test interner helper.
libs/@local/hashql/eval/src/postgres/filter/mod.rs	Updated filter compiler to reference CodeGenerationContext.
libs/@local/hashql/eval/src/orchestrator/partial.rs	Switched to eval-stage Interner in hydration pipeline.
libs/@local/hashql/eval/src/orchestrator/mod.rs	Updated orchestrator to depend on CodeExecutionContext; added allocator-parametric run_in usage in call sites.
libs/@local/hashql/eval/src/orchestrator/events.rs	Added #[inline] on Default impl.
libs/@local/hashql/eval/src/orchestrator/codec/decode/tests.rs	Updated decoder tests to use eval-stage Interner::testing.
libs/@local/hashql/eval/src/orchestrator/codec/decode/mod.rs	Switched decoder interner reference to the eval-stage interner.
libs/@local/hashql/eval/src/lib.rs	Exported new intern module.
libs/@local/hashql/eval/src/intern.rs	Introduced eval-stage Interner convertible from MIR interner (preserves interned identity).
libs/@local/hashql/eval/src/error.rs	Replaced graph-gated diagnostic category variant with an orchestrator-backed variant.
libs/@local/hashql/eval/src/context.rs	Implemented CodeGenerationContext / CodeExecutionContext split and From conversion.
libs/@local/hashql/core/src/graph/linked.rs	Minor Debug impl formatting cleanup + added #[inline] on accessors.
libs/@local/hashql/compiletest/src/suite/eval_postgres.rs	Updated compiletest suite to use CodeGenerationContext and eval interner conversion.
libs/@local/graph/api/src/rest/entity_query_request.rs	Added lint expectation and stubbed compile_query while HashQL API wiring is pending BE-537.

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[codspeed-hq]

Merging this PR will not alter performance

✅ 80 untouched benchmarks

---

_{Comparing bm/be-587-hashql-eval-interner-and-context-restructuring (3d05f60) with bm/be-581-hashql-cached-constructor-produces-bare-fnptr-instead-of (b939729)}

[Copilot]

Pull request overview

Copilot reviewed 21 out of 21 changed files in this pull request and generated 4 comments.

[Copilot]

Pull request overview

Copilot reviewed 21 out of 21 changed files in this pull request and generated 4 comments.