Publish aggregator_program_hash_function as a hint scope variable

[YairVaknin-starkware]

The applicative bootloader's input-loading hint now inserts the aggregator task's program hash function into the execution scope, and the nondet %{ aggregator_program_hash_function %} hint becomes a plain scope read instead of re-deriving the value from the input object. This also lets other applicative-flow bootloaders (the circuit-unpacking one, added later in this stack) share the nondet hint by simply setting the same scope variable in their own input-loading hints.

Stack (1/3): this ← mock circuit verifier hint ← circuit applicative BL hints.

🤖 Generated with Claude Code

---

This change is 

[cursor]

PR Summary

Low Risk
Localized hint wiring with equivalent behavior when the scope is set; new tests lock in the contract.

Overview
The nondet %{ aggregator_program_hash_function %} hint no longer reads program_hash_function from ApplicativeBootloaderInput; it only loads aggregator_program_hash_function from the execution scope and writes it to ap.

prepare_aggregator_simple_bootloader_output_segment now sets that scope value from the aggregator task when applicative input is prepared, so later nondet hints do not depend on which bootloader loaded the input. A new vars::AGGREGATOR_PROGRAM_HASH_FUNCTION constant names the scope key for reuse (e.g. circuit-unpacking applicative bootloader in a follow-up stack).

Unit tests cover the scope read, missing-scope failure, and that prepare inserts the hash function and related bootloader/output state.

^{Reviewed by Cursor Bugbot for commit efc698e. Bugbot is set up for automated code reviews on this repo. Configure here.}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 67.80%. Comparing base (56b4a3a) to head (efc698e).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #393      +/-   ##
==========================================
+ Coverage   66.52%   67.80%   +1.28%     
==========================================
  Files          41       41              
  Lines        5807     5892      +85     
==========================================
+ Hits         3863     3995     +132     
+ Misses       1944     1897      -47     

Files with missing lines	Coverage Δ
...nner-lib/src/hints/applicative_bootloader_hints.rs	55.00% <100.00%> (+55.00%)	⬆️

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[OmriEshhar1]

@OmriEshhar1 reviewed 2 files and all commit messages, and made 1 comment.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on Gali-StarkWare).

[Gali-StarkWare]

@Gali-StarkWare reviewed 2 files and all commit messages, and made 1 comment.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on YairVaknin-starkware).

---

crates/cairo-program-runner-lib/src/hints/applicative_bootloader_hints.rs line 475 at r1 (raw file):

        );
    }
}

Move to a different test file

Code quote:

#[cfg(test)]
mod tests {
    use cairo_vm::Felt252;
    use cairo_vm::hint_processor::builtin_hint_processor::hint_utils::get_ptr_from_var_name;
    use cairo_vm::types::relocatable::Relocatable;
    use cairo_vm::vm::runners::builtin_runner::OutputBuiltinRunner;

    use super::*;
    use crate::test_utils::fill_ids_data_for_test;
    use crate::{PROGRAM_INPUT, ProgramInput};

    #[test]
    fn test_aggregator_program_hash_function_to_ap() {
        let mut vm = VirtualMachine::new(false, false);
        vm.add_memory_segment();
        vm.add_memory_segment();
        let mut exec_scopes = ExecutionScopes::new();
        // Set by the input-loading hint of whichever applicative bootloader is running.
        exec_scopes.insert_value(vars::AGGREGATOR_PROGRAM_HASH_FUNCTION, 2usize);

        aggregator_program_hash_function_to_ap(&mut vm, &mut exec_scopes).unwrap();

        assert_eq!(
            *vm.get_integer(Relocatable::from((1, 0))).unwrap().as_ref(),
            Felt252::from(2)
        );
    }

    #[test]
    fn test_aggregator_program_hash_function_to_ap_requires_scope_variable() {
        let mut vm = VirtualMachine::new(false, false);
        vm.add_memory_segment();
        vm.add_memory_segment();
        let mut exec_scopes = ExecutionScopes::new();
        assert!(aggregator_program_hash_function_to_ap(&mut vm, &mut exec_scopes).is_err());
    }

    #[test]
    fn test_prepare_aggregator_simple_bootloader_output_segment() {
        let mut vm = VirtualMachine::new(false, false);
        vm.add_memory_segment();
        vm.add_memory_segment();
        vm.set_fp(1);
        vm.set_ap(1);
        let ids_data = fill_ids_data_for_test(&["aggregator_output_ptr"]);
        let ap_tracking = ApTracking::new();

        // An output builtin whose pre-hint state points at a fresh segment.
        let applicative_segment = vm.add_memory_segment();
        let mut output_builtin_runner = OutputBuiltinRunner::new(true);
        output_builtin_runner.set_state(OutputBuiltinState {
            base: applicative_segment.segment_index as usize,
            base_offset: 0,
            pages: Default::default(),
            attributes: Default::default(),
        });
        vm.builtin_runners = vec![output_builtin_runner.into()];

        let fibonacci = format!(
            "{}/resources/compiled_programs/test_programs/fibonacci_compiled.json",
            env!("CARGO_MANIFEST_DIR")
        );
        let task = serde_json::json!({
            "type": "RunProgramTask",
            "path": fibonacci,
            "program_hash_function": "blake",
        });
        let mut exec_scopes = ExecutionScopes::new();
        exec_scopes.insert_value(
            PROGRAM_INPUT,
            ProgramInput::Json(
                serde_json::json!({
                    "tasks": [task],
                    "fact_topologies_path": null,
                    "single_page": false,
                    "bootloader_config": {
                        "supported_simple_bootloader_hash_list": ["0x1", "0x2"],
                        "applicative_bootloader_program_hash": "0x3",
                        "supported_cairo_verifier_program_hashes": ["0x4"],
                    },
                    "packed_outputs": [],
                    "aggregator_task": task,
                })
                .to_string(),
            ),
        );

        prepare_aggregator_simple_bootloader_output_segment(
            &mut vm,
            &mut exec_scopes,
            &ids_data,
            &ap_tracking,
        )
        .unwrap();

        // The aggregator task's hash function is exposed for the nondet hint.
        let hash_function: usize = exec_scopes
            .get(vars::AGGREGATOR_PROGRAM_HASH_FUNCTION)
            .unwrap();
        let input: ApplicativeBootloaderInput =
            exec_scopes.get(APPLICATIVE_BOOTLOADER_INPUT).unwrap();
        assert_eq!(
            hash_function,
            input.aggregator_task.program_hash_function as usize
        );

        // The simple bootloader input holds only the aggregator task.
        let simple_bootloader_input: SimpleBootloaderInput =
            exec_scopes.get(vars::SIMPLE_BOOTLOADER_INPUT).unwrap();
        assert_eq!(simple_bootloader_input.tasks.len(), 1);

        // The applicative output builtin state was saved, and the builtin points at the fresh
        // aggregator segment.
        let saved_state: OutputBuiltinState = exec_scopes
            .get(vars::APPLICATIVE_OUTPUT_BUILTIN_STATE)
            .unwrap();
        assert_eq!(saved_state.base, applicative_segment.segment_index as usize);
        let aggregator_output_ptr =
            get_ptr_from_var_name("aggregator_output_ptr", &vm, &ids_data, &ap_tracking).unwrap();
        assert_eq!(
            vm.get_output_builtin_mut().unwrap().get_state().base,
            aggregator_output_ptr.segment_index as usize
        );
    }
}