squash! GitHub action: create a tag to our repo weekly if a new chang…

…e is committed since last tagging

* Use p as prefix of tags instread of v. The original log must be fixed.
* The prefix of the original commit log should be "GitHub Actions."
* @k-takata taught me the usage of git describe/tag.

misc/git-tag-maybe.sh

@@ -3,31 +3,34 @@
 base=5.9
 cal=$(date +%Y%m%d)
 chicken=0
-tag="v${base}.${cal}.${chicken}"
+tag="p${base}.${cal}.${chicken}"
 
-r=0
+if desc=$(git describe --tags --exact-match); then
+	case "${desc}" in
+		p*.0)
+			echo "do nothing because nothing happens since last tagging"
+			exit 0
+			;;
+		*)
+			echo "found a tag but it is not periodical one; create a periodical tag"
+			;;
+	esac
+fi
 
+r=0
 desc=$(git describe --tags --always)
-case "${desc}" in
-	v*)
-		echo "do nothing because nothing happens since last tagging"
-		;;
-	*)
-		printf "%s (%s <= %s)..." "create tag" "${desc}" "${tag}"
-		if git tag "${tag}"; then
-			echo "done"
-			printf "push the tag..."
-			if git push origin --tags; then
-				echo "done"
-			else
-				echo "failed"
-				r=2
-			fi
-		else
-			echo "failed"
-			r=1
-		fi
-		;;
-esac
-
+printf "%s (%s <= %s)..." "create tag" "${desc}" "${tag}"
+if git tag "${tag}"; then
+	echo "done"
+	printf "push the tag..."
+	if git push origin --tags; then
+		echo "done"
+	else
+		echo "failed"
+		r=2
+	fi
+else
+	echo "failed"
+	r=1
+fi
 exit $r