Add pre-commit guard on empty state.

specs/clang/template/.githooks/pre-commit

@@ -6,6 +6,7 @@ FORMAT_FILES=$(
     awk '$1 != "D" && $2 ~ /\.c$|\.h$/ {print $NF}'
 )
 
+if [ -n "$FORMAT_FILES" ]; then
   clang-format -i "$FORMAT_FILES"
-
   git add "$FORMAT_FILES"
+fi

specs/mix/template/.githooks/pre-commit

@@ -6,6 +6,7 @@ FORMAT_FILES=$(
     awk '$1 != "D" && $2 ~ /\.exs?$/ {print $NF}'
 )
 
+if [ -n "$FORMAT_FILES" ]; then
   mix format "$FORMAT_FILES"
-
   git add "$FORMAT_FILES"
+fi

specs/nodejs/template/.githooks/pre-commit

@@ -6,6 +6,7 @@ FORMAT_FILES=$(
     awk '$1 != "D" && $2 ~ /\.jsx?$|\.tsx?$/ {print $NF}'
 )
 
+if [ -n "$FORMAT_FILES" ]; then
   prettier --write "$FORMAT_FILES"
-
   git add "$FORMAT_FILES"
+fi

specs/phoenix/template/.githooks/pre-commit

@@ -6,13 +6,17 @@ MIX_FILES=$(
     awk '$1 != "D" && $2 ~ /\.exs?$/ {print $NF}'
 )
 
+if [ -n "$MIX_FILES" ]; then
+  mix format "$MIX_FILES"
+  git add "$MIX_FILES"
+fi
+
 WEB_FILES=$(
   git --no-pager diff --name-status --no-color --cached | \
     awk '$1 != "D" && $2 ~ /\.jsx?$|\.tsx?$/ {print $NF}'
 )
 
-mix format "$MIX_FILES"
-
+if [ -n "$WEB_FILES" ]; then
   prettier --write "$WEB_FILES"
-
-git add "$MIX_FILES" "$WEB_FILES"
+  git add "$WEB_FILES"
+fi

specs/poetry/template/.githooks/pre-commit

@@ -6,6 +6,7 @@ FORMAT_FILES=$(
     awk '$1 != "D" && $2 ~ /\.py$/ {print $NF}'
 )
 
+if [ -n "$FORMAT_FILES" ]; then
   black --quiet "$FORMAT_FILES"
-
   git add "$FORMAT_FILES"
+fi