pyenv-binary: add the build subcommand

Packaging a version by hand means running `pyenv install`, `pyenv binary
save` and `pyenv binary generate-installer` in turn and keeping the names
they produce in step. `build` runs the three in one pass, so the archive,
its metadata and the definition all come out named after the entry.

* The entry name is given explicitly as `<version>:<entry>`, reusing the
  syntax `pyenv install` already accepts, so a packaged build can sit
  beside a plain source install of the same version
* Entry names that `pyenv install` would not install under (`latest`), or
  that would point outside versions/, are refused before anything is
  compiled rather than after
* Linux only for now, matching `save` and `generate-installer`

plugins/pyenv-binary/README.md

@@ -16,6 +16,22 @@ and dependency metadata exist to catch that.
 
 ## Commands
 
+### `pyenv binary build <version>:<entry> --archive-url <url>`
+
+Builds `<version>` from source under the separate name `<entry>`, packages it
+with `save`, then emits a python-build definition for it with
+`generate-installer`. The archive, metadata and definition land in the current
+directory, named after the entry; host the archive under `<url>` and drop the
+definition into python-build's definition directory. Keeping the entry name
+distinct from the version lets the binary sit alongside a normal source
+install of the same version.
+
+```sh
+pyenv binary build 3.12.7:3.12.7-debian-12 --archive-url https://example.com/binaries
+# writes 3.12.7-debian-12-linux-x86_64.tar.gz, its .meta file and
+# a `3.12.7-debian-12' definition
+```
+
 ### `pyenv binary save <version> [<output-dir>]`
 
 Packs an installed version into `<version>-<platform>.tar.gz` (relative paths)

plugins/pyenv-binary/libexec/pyenv-binary-build

@@ -0,0 +1,83 @@
+#!/usr/bin/env bash
+#
+# Summary: Build a Python version and package it as an installable binary
+#
+# Usage: pyenv binary build <version>:<entry> --archive-url <url>
+#
+#   Builds <version> from source under the separate name <entry>, packages the
+#   result with `pyenv binary save', then emits a python-build definition for
+#   it with `pyenv binary generate-installer'. The archive, metadata and
+#   definition are written to the current directory, named after <entry>.
+#
+#   <version>             A version `pyenv install' knows how to build.
+#   <entry>               The name to build under and to install the binary
+#                         as, e.g. `3.13.14-debian-12'. Keeping it distinct
+#                         from <version> lets the binary sit alongside a
+#                         normal source install of the same version.
+#   --archive-url <url>   Where the archive will be hosted; the definition
+#                         downloads it from <url>/<archive-name>.
+#
+set -e
+[ -n "$PYENV_DEBUG" ] && set -x
+
+# Provide pyenv completions. Only the definitions are useful here: the options
+# `pyenv install' takes are not accepted.
+if [ "$1" = "--complete" ]; then
+  echo --archive-url
+  exec python-build --definitions
+fi
+
+spec=""
+archive_url=""
+
+while [ $# -gt 0 ]; do
+  case "$1" in
+  --archive-url )
+    [ $# -ge 2 ] || { echo "pyenv-binary: --archive-url needs a value" >&2; exit 1; }
+    archive_url="$2"; shift 2 ;;
+  -* )
+    echo "pyenv-binary: unknown option \`$1'" >&2; exit 1 ;;
+  * )
+    [ -z "$spec" ] || { echo "pyenv-binary: unexpected argument \`$1'" >&2; exit 1; }
+    spec="$1"; shift ;;
+  esac
+done
+
+if [ -z "$spec" ] || [ -z "$archive_url" ]; then
+  pyenv-help --usage binary-build >&2
+  exit 1
+fi
+
+case "$spec" in
+*?:?* ) ;;
+* )
+  echo "pyenv-binary: expected <version>:<entry>, e.g. \`3.13.14:3.13.14-debian-12'" >&2
+  exit 1
+  ;;
+esac
+entry="${spec##*:}"
+
+case "$entry" in
+# `pyenv install' reads a trailing `:latest' as part of the version rather than
+# as an alias, so nothing would end up installed under that name.
+latest )
+  echo "pyenv-binary: \`latest' cannot be used as an entry name" >&2
+  exit 1
+  ;;
+# The entry becomes a directory name under versions/. `pyenv install' does not
+# validate the alias, and `save' only checks once the build is done, so refuse
+# a name that could point elsewhere before compiling anything.
+*/* | .. | . )
+  echo "pyenv-binary: invalid entry name \`${entry}'" >&2
+  exit 1
+  ;;
+esac
+
+# `pyenv install' puts a `<version>:<alias>' build under versions/<alias>.
+pyenv-install "$spec"
+pyenv-binary-save "$entry"
+
+# Name the metadata and the archive the way `save' just named them.
+platform="$(uname -s | tr '[:upper:]' '[:lower:]')-$(uname -m)"
+pyenv-binary-generate-installer "${entry}-${platform}.meta" \
+  --archive-url "${archive_url%/}/${entry}-${platform}.tar.gz" -o "$entry"

plugins/pyenv-binary/test/build.bats

@@ -0,0 +1,79 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+# Make the build deterministic: `pyenv-install' just creates the prefix, and
+# the platform tools report a fixed Linux target so the real `save' and
+# `generate-installer' behave the same on any test host.
+stub_build_environment() {
+  create_stub pyenv-install 'mkdir -p "${PYENV_ROOT}/versions/${1##*:}/bin"'
+  create_stub uname 'case "$1" in -s) echo Linux;; -m) echo x86_64;; esac'
+  create_stub getconf 'echo "glibc 2.17"'
+}
+
+@test "completion lists the option and the buildable versions" {
+  create_stub python-build 'echo 3.12.7'
+  run pyenv-binary-build --complete
+  assert_success "--archive-url
+3.12.7"
+}
+
+@test "fails with no arguments" {
+  create_stub pyenv-help "echo usage"
+  run pyenv-binary-build
+  assert_failure "usage"
+}
+
+@test "fails without an archive url" {
+  create_stub pyenv-help "echo usage"
+  run pyenv-binary-build 3.12.7:3.12.7-test
+  assert_failure "usage"
+}
+
+@test "fails when --archive-url has no value" {
+  run pyenv-binary-build 3.12.7:3.12.7-test --archive-url
+  assert_failure "pyenv-binary: --archive-url needs a value"
+}
+
+@test "rejects a second positional argument" {
+  run pyenv-binary-build 3.12.7:3.12.7-test extra --archive-url http://x/b
+  assert_failure "pyenv-binary: unexpected argument \`extra'"
+}
+
+@test "rejects a bare version without an entry name" {
+  run pyenv-binary-build 3.12.7 --archive-url http://x/b
+  assert_failure "pyenv-binary: expected <version>:<entry>, e.g. \`3.13.14:3.13.14-debian-12'"
+}
+
+@test "rejects an entry name containing a slash" {
+  run pyenv-binary-build "3.12.7:foo/bar" --archive-url http://x/b
+  assert_failure "pyenv-binary: invalid entry name \`foo/bar'"
+}
+
+@test "rejects \`latest' as an entry name" {
+  run pyenv-binary-build 3.12:latest --archive-url http://x/b
+  assert_failure "pyenv-binary: \`latest' cannot be used as an entry name"
+}
+
+@test "builds under the entry name and writes the archive and definition" {
+  stub_build_environment
+  cd "${BATS_TEST_TMPDIR}"
+
+  run pyenv-binary-build 3.12.7:3.12.7-test --archive-url http://example.com/binaries
+  assert_success
+  assert [ -d "${PYENV_ROOT}/versions/3.12.7-test" ]
+  assert [ -f "${BATS_TEST_TMPDIR}/3.12.7-test-linux-x86_64.tar.gz" ]
+  assert [ -f "${BATS_TEST_TMPDIR}/3.12.7-test-linux-x86_64.meta" ]
+  run grep '^ARCHIVE_URL=' "${BATS_TEST_TMPDIR}/3.12.7-test"
+  assert_success "ARCHIVE_URL=http://example.com/binaries/3.12.7-test-linux-x86_64.tar.gz"
+}
+
+@test "strips a trailing slash from the archive url" {
+  stub_build_environment
+  cd "${BATS_TEST_TMPDIR}"
+
+  run pyenv-binary-build 3.12.7:3.12.7-test --archive-url http://example.com/binaries/
+  assert_success
+  run grep '^ARCHIVE_URL=' "${BATS_TEST_TMPDIR}/3.12.7-test"
+  assert_success "ARCHIVE_URL=http://example.com/binaries/3.12.7-test-linux-x86_64.tar.gz"
+}