Sketch mode partial execution

[jtran]

• Resolves Partial execution of sketch block only #9434.
• Part of Ability to sketch on things other than default planes #9271. Needs TS support.
• Subsumes/closes Sketch on any plane #9454.

When editing a sketch, current main re-executes the KCL program from the beginning up to and including the sketch block. But this doesn't make sense because mock execution can't call the engine. So any code prior to the sketch block that depends on engine responses will always be wrong.

This PR makes it so that engine execution properly caches needed scene objects in cached "memory" so that when we mock execute for sketch mode, we can mock execute only the sketch block and everything that's needed is available.

As part of this, we allow sketching on custom planes, i.e. from a KCL object or offsetPlane(), and faces. But the user needs to assign it to a variable first. In particular, negative planes like -XY need to be assigned to a variable first. Same with faces by using the new faceOf() to sketch on the face. You need to assign it to a variable first.

face1 = faceOf(solid1, face = tag1)
sketch(on = face1) { }

• Sketch block's on parameter should be allowed to be any expression #9599

Note: This works differently from TypeScript-implemented partial execution because that works by snipping the pipeline expression out of the AST and only executing that. On the other hand, this PR works by marking the sketch block AST node, and the executor skips nodes up to it and exits immediately afterwards.

---

Note

Enables targeted execution for sketch editing and updates geometry primitives to support it.

• Implement sketch-mode partial execution: skip non-relevant code, run only the chosen sketch block; add MockConfig.sketch_block_id, ExecState.sketch_mode, and skip logic in exec_ast.rs
• Persist mock-exec state: replace cached memory with SketchModeState (stack, module infos, and scene_objects) and wire into run paths and LSP
• Scene graph/IDs: use module-local object ID generator; expose scene_object_by_id(_mut) helpers; keep IDs stable when re-executing
• Frontend API: switch to SketchCtor { on: String }, add only_sketch_block, execute new sketch with real engine to seed cache, and support editing/deleting with sketch-mode
• Add Face objects to API and emit face/plane scene objects when created
• Plane refactor: PlaneType → PlaneKind; Plane now tracks initialization via optional object_id; add ensure_sketch_plane_in_engine; update std ops (planes, sketch, gdt, extrude, shapes) and type coercions
• Parser: enforce sketch(on = <identifier>) (no arbitrary expressions)
• Tests and snapshots updated (object ID shifts, new face/plane objects, freedom analysis expectations)

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Project	Deployment	Review	Updated (UTC)
modeling-app	Ready	Preview, Comment	Jan 14, 2026 1:08am

[codspeed-hq]

Merging this PR will improve performance by 91.7%

⚡ 1 improved benchmark
✅ 150 untouched benchmarks
🆕 1 new benchmark
⏩ 93 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
⚡	Simulation	parse_car-wheel-assembly	1,380.3 µs	720 µs	+91.7%
🆕	Simulation	parse_wheel-hub	N/A	14.2 ms	N/A

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_{Comparing jtran/partial-execution (747b39d) with main (794d566)²}

Footnotes

1. 93 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

2. No successful run was found on main (53f56ef) during the generation of this report, so 794d566 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

[adamchalmers]

I don't really understand this change, what's going on here?

[jtran]

When a statement is added to the end of a KCL file, we don't re-execute the whole file. We only execute that new statement.

When executing only the new statement(s) or mock executing for sketch mode, we need the scene objects that were created during the last execution, which are in the execution cache. The cache is read to create the initial module state. Depending on whether it's mock execution or engine execution, it's rehydrated differently. The preserve_mem parameter is another complication. Depending on it, we may use local_state or we may not.

I agree that this is confusing, even before this PR's changes. I researched it some to make #9511, but I still don't completely understand it. To be honest, I don't really know if I got this part all right, except the fact that the tests I made all pass. I can add comments explaining what I know.

[jtran]

I was able to simplify this a little in b875fea. Comments added in 59406a0.

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