fix(check-formatting.sh): use relative directory (#835)

The `bin/check-formatting.sh` script changed its directory to `bin` as
the first step, consequently expecting paths of files to check to be
relative to `bin`, when typically they would be given relative to the
working directory. When not finding a file, the script would just print
a warning, but still exit with error code 0, which is probably the
reason why this went unnoticed for quite a while.

This commit fixes the relative directory issue. Further, when a given
path cannot be checked, we return a non-zero code now. Lastly, the
script would count the number of files with formatting issues and return
that number as error code. This has the issue that if the number of
violating files is a multiple of 256, error code would falsly be returned.

bin/check-formatting.sh

@@ -1,4 +1,5 @@
 #!/usr/bin/env bash
+set -e
 
 print_help() {
     echo "This script verifies if one or more files are formatted using the provided"
@@ -13,8 +14,6 @@ print_help() {
     echo "     warnings are returned for each invalid path."
 }
 
-cd "$(dirname "$0")"
-
 # Get files list
 FILES=()
 while [[ $# -gt 0 ]]
@@ -31,40 +30,24 @@ do
     shift
 done
 
-# Verifies a single file is formatted following .clang-format style
-run_check() {
-    local FILE="$1"
-    CHECK_RESULT=0
-    # Get diff between current content and formatted content
-    local OUTPUT=$(diff -u <(cat "$FILE") <(clang-format --style=file "$FILE"))
-    # Shows diff output only if files are different
-    if [[ $OUTPUT != "" ]]; then
-        echo "$OUTPUT"
-        CHECK_RESULT=1
-    fi
-}
-
-# Result of this script, incremented by one for each unformatted file
+# Result of this script
 RESULT=0
-# List of warnings
-WARNINGS=()
 
 # Iterate files to run format check
 for INDEX in "${!FILES[@]}"; do
     FILE="${FILES[$INDEX]}"
     if [[ -f "$FILE" ]]; then
-        run_check $FILE
-        RESULT=$(( RESULT + CHECK_RESULT ))
+        if ! clang-format --dry-run --Werror "$FILE"; then
+            RESULT=1
+        fi
     elif [[ -d "$FILE" ]]; then
-        WARNINGS+=("Path is a directory: $FILE")
+        echo "Path is a directory: $FILE"
+        RESULT=1
     else
-        WARNINGS+=("File not found: $FILE")
+        echo "File not found: $FILE"
+        RESULT=1
     fi
 done
 
-for INDEX in "${!WARNINGS[@]}"; do
-    echo "${WARNINGS[$INDEX]}"
-done
-
 echo "Done"
 exit $RESULT