1 files changed, 82 insertions, 0 deletions
diff --git a/cargo.sh b/cargo.sh
new file mode 100755
index 0000000..7dacf84
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+++ b/cargo.sh
@@ -0,0 +1,82 @@
+#!/bin/bash
+#
+# Copyright 2023 The Fuchsia Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# This script is a thin wrapper around Cargo that provides human-friendly
+# toolchain names which are automatically translated to the toolchain versions
+# we have pinned in CI.
+#
+#   cargo.sh --version <toolchain-name> # looks up the version for the named toolchain
+#   cargo.sh +<toolchain-name> [...]    # runs cargo commands with the named toolchain
+#   cargo.sh +all [...]                 # runs cargo commands with each toolchain
+#
+# The meta-toolchain "all" instructs this script to run the provided command
+# once for each toolchain (msrv, stable, nightly).
+#
+# A common task that is especially annoying to perform by hand is to update
+# trybuild's stderr files. Using this script:
+#
+#   TRYBUILD=overwrite ./cargo.sh +all test --workspace
+
+set -eo pipefail
+
+function print-usage-and-exit {
+  echo "Usage:"                          >&2
+  echo "  $0 --version <toolchain-name>" >&2
+  echo "  $0 +<toolchain-name> [...]"    >&2
+  echo "  $0 +all [...]"    >&2
+  exit 1
+}
+
+[[ $# -gt 0 ]] || print-usage-and-exit
+
+function pkg-meta {
+  cargo metadata --format-version 1 | jq -r ".packages[] | select(.name == \"zerocopy\").$1"
+}
+
+function lookup-version {
+  VERSION="$1"
+  case "$VERSION" in
+    msrv)
+      pkg-meta rust_version
+      ;;
+    stable)
+      pkg-meta 'metadata.ci."pinned-stable"'
+      ;;
+    nightly)
+      pkg-meta 'metadata.ci."pinned-nightly"'
+      ;;
+    *)
+      echo "Unrecognized toolchain name: '$VERSION' (options are 'msrv', 'stable', 'nightly')" >&2
+      return 1
+      ;;
+  esac
+}
+
+case "$1" in
+  # cargo.sh --version <toolchain-name>
+  --version)
+    [[ $# -eq 2 ]] || print-usage-and-exit
+    lookup-version "$2"
+    ;;
+  # cargo.sh +all [...]
+  +all)
+    echo "[cargo.sh] warning: running the same command for each toolchain (msrv, stable, nightly)" >&2
+    for toolchain in msrv stable nightly; do
+      echo "[cargo.sh] running with toolchain: $toolchain" >&2
+      TOOLCHAIN="$(lookup-version $toolchain)"
+      cargo "+$TOOLCHAIN" ${@:2}
+    done
+    exit 0
+    ;;
+  # cargo.sh +<toolchain-name> [...]
+  +*)
+    TOOLCHAIN="$(lookup-version ${1:1})"
+    cargo "+$TOOLCHAIN" ${@:2}
+    ;;
+  *)
+    print-usage-and-exit
+    ;;
+esac