burnup, the Burn version manager, written in Burn

[S42yt]

burnup is now a rustup-style version manager, written in Burn, that compiles to a ~700 KB native binary.

Versions

• Install:
  • burnup install [version...] accepts a release (26.1 means the newest 26.1.x; v26.1.0 and ^26.1 also work), latest, a branch like master, or a commit.
  • Releases are downloaded prebuilt from burn's GitHub releases.
  • Branches and commits are built from source with burn's scripts/package.sh, reusing one cached clone so later builds are incremental.
• Switch and list: burnup default, burnup list, burnup list --remote, burnup uninstall.
• Update: burnup update rebuilds branch versions whose commit moved, points out a newer release, and updates ash.
• Local builds: burnup link <name> <dir> adds a local build as a version.

Shims and projects

• Shims: ~/.burn/bin/{burn,burni,burnc,burnfmt,burn-lsp,bvm} are small shims that run burnup proxy <tool>, which picks the active version. Each command costs about 2–3 ms extra.
• Choosing a version: the order is BURN_TOOLCHAIN, then the nearest burn.toml with burn = "…" in [package] or a .burn-version file, then the default. A pinned version that isn't installed yet is installed on first use.
• Project commands:
  • burnup pin <version> writes the pin into burn.toml, or .burn-version outside a project.
  • burnup show and burnup which report which version applies.
  • burnup run <version> <cmd…> runs one command with another version.

Setup

• Installer: install.sh is now a small bootstrap. It downloads a prebuilt burnup; otherwise it builds Burn once into toolchains/<ref> and compiles burnup with it (falling back to the interpreter when native compilation isn't available). Then it runs burnup setup.
• burnup setup: picks or installs a default, writes the shims, builds ash into ~/.burn/tools/github.com/burnlang/ash (the same place ash install -g uses), and adds PATH lines to the shell profiles. It also replaces an installation made by the old installer.
• Self-management:
  • burnup self update fetches a prebuilt burnup, or rebuilds it with the default Burn.
  • burnup self uninstall removes everything, including the PATH lines. It deletes all of ~/.burn only if burnup created it.

Tests and CI

• Unit tests: tests/main.bn.
• End-to-end tests: tests/e2e.sh builds a local Burn git repo with tags v1.0.0, v1.1.0 and v2.0.0-beta, plus file:// release archives made from the real toolchain. It covers:
  • setup and the shims;
  • latest resolving to the newest stable release, and prefix matching;
  • default switching and which;
  • pinning in burn.toml and in .burn-version, including subfolders;
  • BURN_TOOLCHAIN, run, and auto-install of a pinned version that was uninstalled;
  • the missing-version error, list --remote, link, and self uninstall.
• Results: the end-to-end tests pass with native burnup and on the interpreter. A from-source bootstrap from GitHub also worked locally: Burn master built, burnup compiled, ash installed, ash init and ash build ran, and self uninstall left the home directory clean.
• CI: runs the tests on native and interpreter, plus a from-source bootstrap job. The release workflow builds burnup-linux-x86_64 and burnup-macos-x86_64 on v* tags.
• Lint: shellcheck and actionlint are clean.

🤖 Generated with Claude Code

https://claude.ai/code/session_01PCXUjgpGnka9y7AHKfnN3w

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