hack: fix unquoted variables in hack scripts to prevent word-splitting

- generate-yamls.sh: quote YAML_OUTPUT_DIR in rm command
- release.sh: quote dirname substitution, REPO_ROOT_DIR in cp, and $@
- verify-codegen.sh: quote REPO_ROOT_DIR inside mktemp call

Unquoted variable expansions and command substitutions break when paths
contain whitespace.

Closes knative#8990
Closes knative#8992
Closes knative#9004

Author: Ankitsinghsisodya

hack/generate-yamls.sh

@@ -45,7 +45,7 @@ readonly YAML_LIST_FILE=${2:?"Second argument must be the output file"}
 if [[ -z "${YAML_OUTPUT_DIR:-}" ]]; then
   readonly YAML_OUTPUT_DIR="$(mktemp -d)"
 fi
-rm -fr ${YAML_OUTPUT_DIR}/*.yaml
+rm -fr "${YAML_OUTPUT_DIR}"/*.yaml
 
 # Generated Knative component YAML files
 readonly EVENTING_CORE_YAML=${YAML_OUTPUT_DIR}/"eventing-core.yaml"

hack/release.sh

@@ -65,12 +65,12 @@ function build_release() {
   # branch since the detail of building may change over time.
   local YAML_LIST="$(mktemp)"
   export TAG
-  $(dirname $0)/generate-yamls.sh "${REPO_ROOT_DIR}" "${YAML_LIST}"
+  "$(dirname "$0")/generate-yamls.sh" "${REPO_ROOT_DIR}" "${YAML_LIST}"
   ARTIFACTS_TO_PUBLISH=$(cat "${YAML_LIST}" | tr '\n' ' ')
   if (( ! PUBLISH_RELEASE )); then
     # Copy the generated YAML files to the repo root dir if not publishing.
-    cp ${ARTIFACTS_TO_PUBLISH} ${REPO_ROOT_DIR}
+    cp "${ARTIFACTS_TO_PUBLISH}" "${REPO_ROOT_DIR}"
   fi
 }
 
-main $@
+main "$@"

hack/verify-codegen.sh

@@ -22,7 +22,7 @@ export GO111MODULE=on
 
 source $(dirname $0)/../vendor/knative.dev/hack/library.sh
 
-readonly TMP_DIFFROOT="$(mktemp -d ${REPO_ROOT_DIR}/tmpdiffroot.XXXXXX)"
+readonly TMP_DIFFROOT="$(mktemp -d "${REPO_ROOT_DIR}/tmpdiffroot.XXXXXX")"
 
 cleanup() {
   rm -rf "${TMP_DIFFROOT}"