conan-1.6-utilities/CLAUDE.md

# CLAUDE.md

Guidance for working on this repository. It records decisions made when the
project was started (August 2026) that are not obvious from the code.

## What this is

Small single-file Python utilities for **Conan 1.x, targeting 1.66**. Not
Conan 2. The first (and so far only) tool is `conandeps.py`; see `README.md`
for what it does and how it is used.

## Hard constraints

- **Conan 1.66 only.** Use the `conans.client.conan_api.ConanAPIV1` API and
  Conan 1 graph internals (`Node.binary`, `Node.dependencies`,
  `conanfile.requires`). Do not introduce Conan 2 APIs or a Conan 2 code path.
- **Python 3.8+.** Conan 1.66 runs on new Pythons too (it falls back to
  `importlib` where `imp` is gone) – verified on 3.14. It does emit
  SyntaxWarnings from its own modules there, which `conandeps.py` silences
  before importing `conans`; keep `conans` imports deferred so that filter
  is in place first. `requires-python` in `pyproject.toml` and the PEP 723
  header must stay in sync.
- **All development runs inside the container.** Use `./dev.sh <cmd>` for
  every python/pytest/ruff/uv invocation. Never run `conan` against the
  host's `~/.conan`; never `pip install` on the host. Rebuild the image with
  `./dev.sh build` after touching `Containerfile`.
- **Never depend on the private remote.** The real remote is called `knor`
  and only exists on the machine where the tool is used. Tests must use the
  local `conan_server` fixture in `tests/test_conandeps.py`.

## Design decisions (and why)

- **Binary availability is computed via Conan's graph, not `conan search`.**
  The graph is built once per build type through `ConanAPIV1.info()` and each
  node's `binary` status is read. This honours `package_id()` overrides,
  options and `default_package_id_mode` exactly like `conan install`. Do not
  replace this with settings-dict matching against `conan search` output.
- **"Missing" means missing for the exact profile.** Not "no binary with
  that build_type at all".
- **Only the remote counts, and the source is always shown.** Conan says
  `Cache` for a locally cached binary without asking the remote, so
  `_RemoteIndex` verifies cache hits with `search_packages` on the remote.
  Cache-only binaries are reported as `not available` and count as a
  problem (exit 1). Every available cell names the remote. The user rejected
  an opt-in flag for this – it is the tool's core question.
- **Overrides are parsed from Conan's WARN output.** Conan 1 does not record
  overrides on the graph; `Requirements.update()` mutates `req.ref` in place
  and only emits `"<pkg>: requirement <old> overridden by <who> to <new>"`.
  `conandeps` captures the output stream with a non-coloured `ConanOutput`
  and matches `_OVERRIDE_RE`. `test_overrides` pins this format – if a Conan
  patch release changes the wording, that test is the alarm.
- **Both explicit and implicit overrides are reported.** `override=True`
  requirements are collected from `conanfile.requires` to label an override
  as explicit; everything else parsed from the WARN lines is implicit.
- **`range_ref` is not a version range after an override.** Conan reuses
  `Requirement.range_ref` to hold the pre-override reference, so only treat
  it as a range when `req.version_range` is truthy.
- **Single file, stdlib + Conan only.** No third-party deps beyond Conan.
  Packaging is hatchling with `only-include = ["conandeps.py"]`; the PEP 723
  header makes the file usable via `uv run conandeps.py` without a checkout.
- **Exit codes:** `0` fine, `1` missing binaries, `2` Conan error. CI relies
  on this.
- **Tables and colour, consistently.** Dependencies, missing binaries and
  overrides are all rendered through the same `_table()` helper (text) and
  `_html_table()` (HTML). Colour is an aid only – every state is also spelled
  out in words – and `_table()` aligns on *visible* width so ANSI codes never
  break columns. `--color auto` is the default (terminal + no `NO_COLOR`).
- **stdout is the report, stderr is progress.** Graph resolution against a
  remote takes a while; progress lines (`_progress`) and `--verbose` live
  Conan output go to stderr only, so stdout can be redirected to a file.

## Workflow

- Lint/format: `./dev.sh ruff check .` and `./dev.sh ruff format .`
  (config in `pyproject.toml`, target py38, line length 100). Run
  `shellcheck dev.sh` after editing the wrapper.
- Tests: `./dev.sh python -m pytest`. The fixture spins up `conan_server`
  on a free port with a pre-written `server.conf` (the port cannot be given
  on the command line), creates fake packages whose `build()` does nothing,
  uploads them, then wipes the cache so binaries can only come from the
  remote. Fake recipes need `--build=missing` at create time because
  dependencies' binaries are deliberately incomplete.
- Dependencies: `uv.lock` is committed; regenerate with `./dev.sh uv lock`
  after changing `pyproject.toml`.
- Commits: atomic, no `--amend`; run ruff + pytest + shellcheck before
  committing. Add a memory of anything a future session could not derive
  from the repository.

## Adding another tool

Follow the `conandeps.py` pattern: one executable file with a module
docstring explaining *how* and *why*, a PEP 723 header, a `main(argv)` that
returns an exit code, a `[project.scripts]` entry, an `only-include` entry in
`pyproject.toml`, tests under `tests/` using the shared `conan_env` fixture,
and a section in `README.md`.