# ccp4

CCP4 suite (binary distribution, bundled with SHELX and ARP/wARP) for
macromolecular crystallography. https://www.ccp4.ac.uk/

- Vendor tarball install: default `prep` downloads the ~5 GB tarball
  (cached in `$PMODULES_DISTFILESDIR`), `install` untars it into `$PREFIX`
  and runs `BINARY.setup`.
- Non-interactive: the CCP4 licence is pre-agreed via `.agree2ccp4v6`
  before `BINARY.setup` runs, so the build never prompts.
- No `shasums:`: the download link is session-gated (`sid=` expires), so
  the checksum cannot be pinned ahead of the first fetch. After the first
  successful build, `sha256sum` the cached tarball and add it if wanted.
- Module version is the series (`9.0`); minor updates (9.0.xxx) come via
  the CCP4 update manager inside the installation.

## Build on Ra

One-time per user: put the Pmodules build tmp and download cache on
/das instead of /var/tmp and $HOME (the tarball alone would blow the
home quota):

```bash
mkdir -p /das/work/p21/p21515/.cache/Pmodules/distfiles ~/.Pmodules
cat > ~/.Pmodules/Pmodules.yaml <<'EOF'
tmp_dir: /das/work/p21/p21515/.cache/Pmodules
download_dir: /das/work/p21/p21515/.cache/Pmodules/distfiles
EOF
```

Then:

```bash
module use unstable && module load modbuild/2.1.3
cd ccp4
modbuild build --prep 9.0   # download/cache only; also verifies tmp_dir took effect
modbuild build 9.0
```

If the download fails (expired sid), fetch a fresh link from
https://www.ccp4.ac.uk/download/ and update `files/config.yaml`, or drop a
hand-downloaded tarball into the distfiles dir under the `name:` given in
`files/config.yaml`.

## Known failure modes

- **"done" but broken install**: modbuild has no errexit in hooks — errors in
  `pbuild::install` used to scroll by and the build still reported done. The
  build script now `std::die`s on every critical step.
- **Truncated download reused silently**: an interrupted `curl` leaves a
  partial file in the distfiles dir, and prep reuses any file it finds there
  (no integrity check without `shasums:`). Symptom:
  `gzip: stdin: unexpected end of file`. Fix:
  ```bash
  rm ~/.cache/Pmodules/distfiles/ccp4-9.0-shelx-arp-x86_64.tar.gz
  modbuild build --clean-install 9.0
  # or verify by hand before building:
  gzip -t ~/.cache/Pmodules/distfiles/ccp4-9.0-shelx-arp-x86_64.tar.gz
  ```
- The tarball unpacks to `ccp4-9` (not `ccp4-9.0` as the CCP4 install doc
  implies); the build globs `ccp4-*/` instead of assuming the name.

## Verify

```bash
module use MX unstable && module load ccp4/9.0
which refmac5 ccp4i2
echo $CCP4          # should point into /opt/psi/MX/ccp4/9.0/ccp4 (-> ccp4-9)
```

Bundled SHELX and ARP/wARP still need their own academic registrations.