Update action to not taint the working directory (#113)

Issue #97 indicates that the action leaves files behind in the working
directory.

This change updates the action to use `$RUNNER_TEMP`, per
https://docs.github.com/en/actions/learn-github-actions/variables#default-environment-variables.

.github/workflows/test.yml

@@ -34,6 +34,9 @@ jobs:
       - run: ./setup-cli/assert/version.sh $(cat ./setup-cli/VERSION)
         shell: bash
 
+      - run: ./setup-cli/assert/clean.sh
+        shell: bash
+
   action_with_version:
     runs-on: ${{ matrix.os }}
 
@@ -60,6 +63,9 @@ jobs:
       - run: ./setup-cli/assert/version.sh 0.200.0
         shell: bash
 
+      - run: ./setup-cli/assert/clean.sh
+        shell: bash
+
   install:
     runs-on: ${{ matrix.os }}
 

assert/clean.sh

@@ -0,0 +1,16 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+function list_files() {
+    find . -not -path '.' -not -path './setup-cli*'
+}
+
+# The ./setup-cli path is expected to be present.
+if [[ "$(list_files)" != "" ]]; then
+    echo "Found unexpected files in working directory:"
+    list_files
+    exit 1
+else
+    exit 0
+fi

setup_release.sh

@@ -2,11 +2,6 @@
 
 set -euo pipefail
 
-if test -d .bin; then
-  echo "Directory .bin found; assuming CLI was already downloaded"
-  exit 0
-fi
-
 # Pull latest version from VERSION file if not set.
 if [ -z "${VERSION:-}" ]; then
     VERSION=$(cat "$(dirname "$0")"/VERSION)
@@ -43,6 +38,9 @@ ARM64)
 ;;
 esac
 
+# Change into temporary directory.
+cd "$RUNNER_TEMP"
+
 # Download release archive.
 curl -L -s -O "https://github.com/databricks/cli/releases/download/v${VERSION}/${FILE}.zip"
 

setup_snapshot.sh

@@ -38,11 +38,6 @@ function cli_snapshot_directory() {
     echo $dir
 }
 
-if test -d .bin; then
-  echo "Directory .bin found; assuming CLI was already downloaded"
-  exit 0
-fi
-
 # Default to main branch if branch is not specified.
 if [ -z "$BRANCH" ]; then
   BRANCH=main
@@ -71,6 +66,9 @@ macOS)
     ;;
 esac
 
+# Change into temporary directory.
+cd "$RUNNER_TEMP"
+
 gh run download "$last_successful_run_id" -n "$artifact" -D .bin
 
 dir="$PWD/.bin/$(cli_snapshot_directory)"