Check commit existed before running some commands

Makefile

@@ -38,6 +38,9 @@ install:
 			if ! grep "$(COMMAND)" not_need_git_repo >/dev/null; then \
 				cat ./helper/is-git-repo >> $(TEMPFILE); \
 			fi; \
+			if grep "$(COMMAND)" need_git_commit >/dev/null; then \
+				cat ./helper/has-git-commit >> $(TEMPFILE); \
+			fi; \
 			tail -n +2 bin/$(COMMAND) >> $(TEMPFILE); \
 			cp -f $(TEMPFILE) $(DESTDIR)$(BINPREFIX)/$(COMMAND); \
 		fi; \

helper/has-git-commit

@@ -0,0 +1,14 @@
+#
+# check whether current directory contains any git commit
+#
+
+has_git_commit() {
+  git rev-parse --short HEAD > /dev/null 2>&1
+  result=$?
+  if test $result != 0; then
+    >&2 echo 'Not git commit found!'
+    exit $result
+  fi
+}
+
+has_git_commit

need_git_commit

@@ -0,0 +1,13 @@
+# A list of the commands that require has_git_commit(), and should have
+# it included in the "built" version of the command
+git-authors
+git-back
+git-changelog
+git-commits-since
+git-count
+git-effort
+git-local-commits
+git-reauthor
+git-stamp
+git-summary
+git-undo