Have the pre-commit hook also fix end-of-file nl

2 files changed, 32 insertions, 1 deletions

diff --git a/dev/tools/check-eof-newline.sh b/dev/tools/check-eof-newline.sh
index 9e4c8661d..c5a654e21 100755
--- a/dev/tools/check-eof-newline.sh
+++ b/dev/tools/check-eof-newline.sh
@@ -1,12 +1,32 @@
 #!/usr/bin/env bash
 
+# Usage: check-eof-newline.sh [--fix] FILES...
+# Detect missing end of file newlines for FILES.
+# Files are skipped if untracked by git and depending on gitattributes.
+# With --fix, automatically append a newline.
+# Exit status: 1 if any file had a missing newline, 0 otherwise
+# (regardless of --fix).
+
+FIX=
+if [ "$1" = --fix ];
+then
+   FIX=1
+   shift
+fi
+
 CODE=0
 for f in "$@"; do
     if git ls-files --error-unmatch "$f" >/dev/null 2>&1 && \
            git check-attr whitespace -- "$f" | grep -q -v -e 'unset$' -e 'unspecified$' && \
            [ -n "$(tail -c 1 "$f")" ]
     then
-        echo "No newline at end of file $f!"
+        if [ -n "$FIX" ];
+        then
+            echo >> "$f"
+            echo "Newline appended to file $f!"
+        else
+            echo "No newline at end of file $f!"
+        fi
         CODE=1
     fi
 done
diff --git a/dev/tools/pre-commit b/dev/tools/pre-commit
index 59cc84856..0cd0a0b70 100755
--- a/dev/tools/pre-commit
+++ b/dev/tools/pre-commit
@@ -5,6 +5,17 @@
 
 set -e
 
+CODE=0
+git diff --cached --name-only -z | xargs -0 dev/tools/check-eof-newline.sh --fix || CODE=1
+
+if [ $CODE -ne 0 ]
+then
+    1>&2 echo "Some files had newline errors; they have been fixed in the working tree."
+    1>&2 echo "Make sure to add them before committing."
+    1>&2 echo "This may fix itself if you were using git commit -a, and you try again."
+    exit 1
+fi
+
 if git diff-index --check --cached HEAD >/dev/null 2>&1 ;
 then
     :