chore: checkpoint before Python removal

vendor/iri-string/.woodpecker/scripts/prepare-toolchain.sh

@@ -0,0 +1,25 @@
+#!/bin/sh
+set -eu
+
+cd "$(readlink -f "$(dirname "$0")/../..")"
+
+set -x
+
+RUST_CHANNEL="$1"
+
+# Use the preset for CI environment.
+cp .woodpecker/cargo-config.toml ${CARGO_HOME}/config.toml
+
+# The repository should not have a directory which would be used as the cached `$RUSTUP_HOME`.
+CACHED_RUSTUP_HOME=${CI_WORKSPACE}/.tmp-rustup-home && test ! -e ${CACHED_RUSTUP_HOME}
+
+# Copy the pre-installed toolchains of the Docker container into the new `$RUSTUP_HOME`.
+cp -a /usr/local/rustup ${CACHED_RUSTUP_HOME} && test -d ${CACHED_RUSTUP_HOME}
+
+# Use the new `$RUSTUP_HOME` variable.
+export RUSTUP_HOME=${CACHED_RUSTUP_HOME}
+
+# Install the toolchain of the specified version (if not yet available locally).
+rustup update --no-self-update ${RUST_CHANNEL} && rustup default ${RUST_CHANNEL}
+
+rustc --version && cargo --version