build

name	build
description	Builds the GenVM project. Use after making code changes to compile Rust binaries.

To build the GenVM project:

Reconfiguring

If ninja fails with missing and no known rule to make it (e.g., after adding/removing/renaming source files), regenerate the build file first:

./configure.rb

This runs the configure.rb Ruby script at the project root, which regenerates build/build.ninja with the current file list.

Building

Build all Rust binaries:

nix develop .#full --command bash .claude/skills/build/scripts/run-ninja.sh -C build all/bin

This runs ninja silently and only shows output on failure (to save tokens).

Available ninja targets:

Target	Description
all	Build everything
all/bin	Build all Rust binaries
all/data	Build data about runners using Nix
codegen	Run code generation

Output locations:

• out/bin/genvm-modules - modules binary
• out/executor/<version>/bin/genvm - executor binary (one dir per built version, e.g. out/executor/v0.3.0-rc7/; the concrete version comes from executors/<line>.x/manifest.json and is recorded in build/info.json)

Runners

Runners can only be built on x86_64 using the all target. On other platforms, download them instead.

Download runners:

nix develop .#full --command python3 build/out/bin/post-install.py --create-venv false --default-step false --runners-download true --error-on-missing-executor false

Runner Development Workflow

To develop/modify a runner (e.g., cloudpickle):

1. Enable dev mode: Set runners/support/versions/dev-mode.nix to true

2. Set hash to "test": In runners/support/versions/current.nix, set the runner's hash to "test"

3. Make your modifications and run tests With dev-mode enabled and hash set to "test", you can build and run tests.

4. Disable dev mode: Set runners/support/versions/dev-mode.nix back to false. The build will now tell you to set hashes to null.

5. Set hashes to null and build: Set the runner's hash (and dependent runners' hashes) to null, then build:

   nix develop .#full --command ninja -C build all
   

   The build will fail with a hash mismatch showing the new hash.

6. Update hashes: Copy the new hash from the error message back into hashes.nix. Repeat for dependent runners.

7. Rebuild to verify: Run the build again to confirm all hashes are correct.