## This repository: Crafter.Build

A C++26 modules build system that builds itself. The stated design is
`README.md` (the manual) and `AGENTS.template.md` (the contributor guide;
`AGENTS.md` is written from it by a crafter-build build or test run, not
by `build.sh`, and is not in the tree).
Its "Design rules" and "Security considerations" are the owner's
decisions: a range that departs from one without saying so is a finding;
whether one should change is the owner's call, not a defect of the range.
Among them, for CI, which holds the workflow's token and the signing key
its runner mounts: no secret is added to the workflow, and the
environment is never echoed in it.

The layers: the library (`interfaces/`, `implementations/`), which the
executable wraps and every `project.cpp` is compiled against; this
repository's own `project.cpp`; `build.sh`, the bootstrap that builds the
tool without the tool; the Flatpak (`packaging/flatpak/`), which bundles
the LLVM users build with; CI (`.forgejo/workflows/ci.yaml`). A target
difference branches on `cfg.target` at run time, never on the host; an
output path goes through `BinDir()`, `BuildDir()` or `PcmDir()`; whatever
changes what gets compiled or bundled reaches `VariantId()`.

Search first: the partitions' own helpers (`RunBuildCommand`,
`RunCommandChecked`, `Progress::Diagnostic`, `ApplyStandardArgs`,
`HostTarget`, `GitProject`, `LocalProject`); the Crafter.* libraries the
tree already uses, cloned under `~/.cache/crafter.build/external/`; libc++
and clang as the host installs them (`/run/host/usr/include/c++/v1`,
`/run/host/usr/lib/clang/`); git, cmake and flatpak-builder.

Commit shape here: a fix, its test and its README change are separate
commits when each stands on its own, in that order, and a bug fix ships
with a test that fails before it. That split is not a later commit
repairing an earlier one.

Compatibility: the `project.cpp` of every sibling repository beside this
checkout (`../Crafter.*/project.cpp`) and of every user compiles against
what `interfaces/` exports and is loaded by the binary; the CLI, the
`CRAFTER_BUILD_*` variables, the cache an older version left under
`~/.cache/crafter.build/` and the `bin/` layout CI globs are contracts too.
Users get a push to master through the Flatpak's `beta` branch and a tag
through `stable`. A change an existing `project.cpp` does not survive is a
finding unless the range documents, in the README, what users must change.