fix(brew-bump.sh): add checks and handle errors

ci/steps/brew-bump.sh

@@ -5,6 +5,21 @@ main() {
   cd "$(dirname "$0")/../.."
   # Only sourcing this so we get access to $VERSION
   source ./ci/lib.sh
+  source ./ci/steps/steps-lib.sh
+
+  echo "Checking environment variables"
+
+  # We need VERSION to bump the brew formula
+  if is_env_var_set "VERSION"; then
+    echo "VERSION is not set"
+    exit 1
+  fi
+
+  # We need HOMEBREW_GITHUB_API_TOKEN to push up commits
+  if is_env_var_set "HOMEBREW_GITHUB_API_TOKEN"; then
+    echo "HOMEBREW_GITHUB_API_TOKEN is not set"
+    exit 1
+  fi
 
   # NOTE: we need to make sure cdrci/homebrew-core
   # is up-to-date
@@ -13,27 +28,65 @@ main() {
   echo "Cloning cdrci/homebrew-core"
   git clone https://github.com/cdrci/homebrew-core.git
 
+  # Make sure the git clone step is successful
+  if directory_exists "homebrew-core"; then
+    echo "git clone failed. Cannot find homebrew-core directory."
+    ls -la
+    exit 1
+  fi
+
   echo "Changing into homebrew-core directory"
-  cd homebrew-core && pwd
+  pushd homebrew-core && pwd
 
-  echo "Adding Homebrew/homebrew-core as $(upstream)"
+  echo "Adding Homebrew/homebrew-core"
   git remote add upstream https://github.com/Homebrew/homebrew-core.git
 
+  # Make sure the git remote step is successful
+  if ! git config remote.upstream.url > /dev/null; then
+    echo "git remote add upstream failed."
+    echo "Could not find upstream in list of remotes."
+    git remote -v
+    exit 1
+  fi
+
+  # TODO@jsjoeio - can I somehow check that this succeeded?
   echo "Fetching upstream Homebrew/hombrew-core commits"
   git fetch upstream
 
+  # TODO@jsjoeio - can I somehow check that this succeeded?
   echo "Merging in latest Homebrew/homebrew-core changes"
   git merge upstream/master
 
   echo "Pushing changes to cdrci/homebrew-core fork on GitHub"
+
+  # GIT_ASKPASS lets us use the password when pushing without revealing it in the process list
+  # See: https://serverfault.com/a/912788
+  PATH_TO_GIT_ASKPASS="$HOME/git-askpass.sh"
   # Source: https://serverfault.com/a/912788
   # shellcheck disable=SC2016,SC2028
-  echo '#!/bin/sh\nexec echo "$HOMEBREW_GITHUB_API_TOKEN"' > "$HOME"/.git-askpass.sh
+  echo 'echo $HOMEBREW_GITHUB_API_TOKEN' > "$PATH_TO_ASKPASS"
+
+  # Make sure the git-askpass.sh file creation is successful
+  if file_exists "$PATH_TO_GIT_ASKPASS"; then
+    echo "git-askpass.sh not found in $HOME."
+    ls -la "$HOME"
+    exit 1
+  fi
+
   # Ensure it's executable since we just created it
-  chmod +x "$HOME/.git-askpass.sh"
-  # GIT_ASKPASS lets us use the password when pushing without revealing it in the process list
-  # See: https://serverfault.com/a/912788
-  GIT_ASKPASS="$HOME/.git-askpass.sh" git push https://cdr-oss@github.com/cdr-oss/homebrew-core.git --all
+  chmod +x "$PATH_TO_GIT_ASKPASS"
+
+  # Make sure the git-askpass.sh file is executable
+  if is_executable "$PATH_TO_GIT_ASKPASS"; then
+    echo "$PATH_TO_GIT_ASKPASS is not executable."
+    ls -la "$PATH_TO_GIT_ASKPASS"
+    exit 1
+  fi
+
+  # Export the variables so git sees them
+  export HOMEBREW_GITHUB_API_TOKEN="$HOMEBREW_GITHUB_API_TOKEN"
+  export GIT_ASKPASS="$PATH_TO_ASKPASS"
+  git push https://cdr-oss@github.com/cdr-oss/homebrew-core.git --all
 
   # Find the docs for bump-formula-pr here
   # https://github.com/Homebrew/brew/blob/master/Library/Homebrew/dev-cmd/bump-formula-pr.rb#L18
@@ -48,8 +101,14 @@ main() {
   fi
 
   # Clean up and remove homebrew-core
-  cd ..
+  popd
   rm -rf homebrew-core
+
+  # Make sure homebrew-core is removed
+  if directory_exists "homebrew-core"; then
+    echo "rm -rf homebrew-core failed."
+    ls -la
+  fi
 }
 
 main "$@"

ci/steps/steps-lib.sh

@@ -0,0 +1,47 @@
+#!/usr/bin/env bash
+
+# This is a library which contains functions used inside ci/steps
+#
+# We separated it into it's own file so that we could easily unit test
+# these functions and helpers
+
+# Checks whether and environment variable is set.
+# Source: https://stackoverflow.com/a/62210688/3015595
+is_env_var_set() {
+  local name="${1:-}"
+  if test -n "${!name:-}"; then
+    return 0
+  else
+    return 1
+  fi
+}
+
+# Checks whether a directory exists.
+directory_exists() {
+  local dir="${1:-}"
+  if [[ -d "${dir:-}" ]]; then
+    return 0
+  else
+    return 1
+  fi
+}
+
+# Checks whether a file exists.
+file_exists() {
+  local file="${1:-}"
+  if test -f "${file:-}"; then
+    return 0
+  else
+    return 1
+  fi
+}
+
+# Checks whether a file is executable.
+is_executable() {
+  local file="${1:-}"
+  if [ -f "${file}" ] && [ -r "${file}" ] && [ -x "${file}" ]; then
+    return 0
+  else
+    return 1
+  fi
+}

test/scripts/steps-lib.bats

@@ -0,0 +1,46 @@
+#!/usr/bin/env bats
+
+SCRIPT_NAME="steps-lib.sh"
+SCRIPT="$BATS_TEST_DIRNAME/../../ci/steps/$SCRIPT_NAME"
+
+source "$SCRIPT"
+
+@test "is_env_var_set should return 1 if env var is not set" {
+  run is_env_var_set "ASDF_TEST_SET"
+  [ "$status" = 1 ]
+}
+
+@test "is_env_var_set should return 0 if env var is set" {
+  ASDF_TEST_SET="test" run is_env_var_set "ASDF_TEST_SET"
+  [ "$status" = 0 ]
+}
+
+@test "directory_exists should 1 if directory doesn't exist" {
+  run directory_exists "/tmp/asdfasdfasdf"
+  [ "$status" = 1 ]
+}
+
+@test "directory_exists should 0 if directory exists" {
+  run directory_exists "$(pwd)"
+  [ "$status" = 0 ]
+}
+
+@test "file_exists should 1 if file doesn't exist" {
+  run file_exists "hello-asfd.sh"
+  [ "$status" = 1 ]
+}
+
+@test "file_exists should 0 if file exists" {
+  run file_exists "$SCRIPT"
+  [ "$status" = 0 ]
+}
+
+@test "is_executable should 1 if file isn't executable" {
+  run is_executable "hello-asfd.sh"
+  [ "$status" = 1 ]
+}
+
+@test "is_executable should 0 if file is executable" {
+  run is_executable "$SCRIPT"
+  [ "$status" = 0 ]
+}