feat: sanitize the config file before sourcing

.github/workflows/ci.yml

@@ -14,4 +14,4 @@ jobs:
 
     - name: run tests
       run: |
-        for tst in test/*; do $tst; done
+        for tst in test/*.sh; do $tst; done

lib/misc_funcs.sh

@@ -87,7 +87,7 @@ function load_config() {
 
   if [ -f $custom_config_file ];
   then
-    source $custom_config_file
+    source_file $custom_config_file
     assert_elixir_version_set $custom_config_file
   fi
 
@@ -243,3 +243,14 @@ function fix_elixir_version() {
     exit 1
   fi
 }
+
+function source_file() {
+  local bkup_file=$(mktemp /tmp/buildpack_source_file_bkup.XXXX)
+
+  cp $1 $bkup_file
+
+  # sanitize the file to avoid any non-printable characters
+  LC_ALL=C tr -cd '\11\12\15\40-\176' < $bkup_file > $1
+  source $1
+  mv $bkup_file $1
+}

test/clean_config_file.sh

@@ -0,0 +1,40 @@
+#!/usr/bin/env bash
+
+set -e
+
+SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )"
+source $SCRIPT_DIR/.test_support.sh
+
+# include source file
+source $SCRIPT_DIR/../lib/misc_funcs.sh
+
+# override functions
+reset_test() {
+  EXIT_CODE=0
+  OUTPUT_LINES=()
+}
+
+exit() {
+  EXIT_CODE=$1
+}
+output_line() {
+  OUTPUT_LINES+=("$1")
+}
+
+
+# TESTS
+######################
+suite "clean_config_file"
+
+  test "handles unicode characters gracefully"
+
+    build_path="${SCRIPT_DIR}/config_files/unicode_chars"
+    load_config
+
+    [ "$EXIT_CODE" == 0 ]
+    [ "${elixir_version}" == "v1.19.1" ]
+    [ "${erlang_version}" == "27.3.4" ]
+
+
+
+PASSED_ALL_TESTS=true