Add shellcheck script

.githooks/pre-commit

@@ -11,44 +11,26 @@ set -euo pipefail
 # we need to resolve it before we can make path relative to this script's file.
 . "$(dirname "$(readlink -f "${BASH_SOURCE[0]}")")/../scripts/lib.sh"
 
-function command_exists() {
-  bin_name=$(basename "$1")
-
-  if command -v "$1" &> /dev/null; then
-    return 0
-  fi
-
-  warn "$bin_name CLI was not found. Ignoring it..."
-  return 1
-}
-
 files=$(git diff --cached --name-only --diff-filter=ACMR | sed 's| |\\ |g')
 
 if [[ -z "$files" ]]; then
   info "No files changed. Exiting the pre-commit hook..."
   exit 0
 fi
 
-if command_exists typos; then
-  echo "$files" | step xargs typos
-fi
+echo "$files" | step xargs typos
 
-if command_exists npx; then
-  echo "$files" | step xargs npx prettier --ignore-unknown --write
-fi
+./scripts/shellcheck.sh
 
-if command_exists cargo; then
-  # `rustfmt` doesn't ignore non-rust files automatically
-  rust_files=$(echo "$files" | { grep -E '\.rs$' || true; })
+echo "$files" | step xargs npx prettier --ignore-unknown --write
 
-  if [[ -n "$rust_files" ]]; then
-    echo "$rust_files" | step xargs cargo fmt --manifest-path native/Cargo.toml --
-  fi
+# `rustfmt` doesn't ignore non-rust files automatically
+rust_files=$(echo "$files" | { grep -E '\.rs$' || true; })
+if [[ -n "$rust_files" ]]; then
+  echo "$rust_files" | step xargs cargo fmt --manifest-path native/Cargo.toml --
 fi
 
-if command_exists mix; then
-  echo "$files" | step xargs mix format
-fi
+echo "$files" | step xargs mix format
 
 # Add the modified/prettified files to staging
 echo "$files" | step xargs git add

.github/workflows/ci.yml

@@ -41,6 +41,14 @@ jobs:
       - uses: actions/checkout@v5
       - uses: crate-ci/typos@master
 
+  shellcheck:
+    name: Shellcheck
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v5
+      - run: ./scripts/install/shellcheck.sh
+      - run: ./scripts/shellcheck.sh
+
   cargo:
     name: Rust Linting and Unit Tests
     runs-on: ubuntu-latest

docker/app/purge-cache

@@ -1,4 +1,5 @@
 #!/usr/bin/env sh
+# shellcheck disable=SC2034
 
 # Run your custom purge command here.
 #

docker/app/run-test

@@ -11,10 +11,10 @@ mix format --check-formatted
 
 # Sleep to allow OpenSearch to finish initializing
 # if it's not done doing whatever it does yet
-echo -n "Waiting for OpenSearch"
+printf "Waiting for OpenSearch"
 
 until wget -qO - opensearch:9200; do
-  echo -n "."
+  printf "."
   sleep 2
 done
 

scripts/install/shellcheck.sh

@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+. "$(dirname "${BASH_SOURCE[0]}")/../lib.sh"
+
+version=0.11.0
+
+fetch https://github.com/koalaman/shellcheck/releases/download/v$version/shellcheck-v$version.linux.x86_64.tar.xz \
+  | step tar -xJf - -C /usr/local/bin --strip-components=1 shellcheck-v$version/shellcheck

scripts/lib.sh

@@ -80,3 +80,15 @@ function colorize_command {
   # and we use bash >= v5. If this ever becomes a problem, you know the why.
   echo -e "\033[1;32m${program}\033[0m ${args[*]}"
 }
+
+# `curl` wrapper with better defaults for non-interactive scripts
+function fetch {
+  step curl \
+    --fail \
+    --silent \
+    --show-error \
+    --location \
+    --retry 5 \
+    --retry-all-errors \
+    "$@"
+}

scripts/shellcheck.sh

@@ -0,0 +1,23 @@
+#!/usr/bin/env bash
+#
+# This script runs shellcheck on all shell scripts in the repository.
+# It exists because shellcheck doesn't attempt to automatically discover
+# shell scripts and requires specifying the file paths explicitly.
+#
+# This is somewhat understandable, because not all shell scripts use
+# obvious file extensions like `.sh`. So, we discover such files by
+# checking if they have one of the expected shebang lines at the beginning.
+
+set -euo pipefail
+
+. "$(dirname "${BASH_SOURCE[0]}")/lib.sh"
+
+function shell_script_files {
+  git ls-files "*.sh"
+  git grep --files-with-matches '^#!/usr/bin/env bash'
+  git grep --files-with-matches '^#!/usr/bin/env sh'
+}
+
+mapfile -t files < <(shell_script_files "$@" | sort -u)
+
+step shellcheck --source-path SCRIPTDIR "${files[@]}"