git-psykorebase: determine branch names with bash pattern substitution (#1073)

Co-authored-by: Dan Goodliffe <[email protected]>

Author: rascalDan

bin/git-psykorebase

@@ -50,15 +50,13 @@ fi
 
 if [[ "$CONTINUE" == "yes" ]]; then
     TARGET_BRANCH=$(current_branch)
-    set "$(echo "$TARGET_BRANCH" | sed -e "s/-rebased-on-top-of-/\n/g")"
-    if [[ $# != 2 ]]; then
+    SECONDARY_BRANCH=${TARGET_BRANCH%"-rebased-on-top-of-"*}
+    PRIMARY_BRANCH=${TARGET_BRANCH#*"-rebased-on-top-of-"}
+    if [[ "${SECONDARY_BRANCH}-rebased-on-top-of-${PRIMARY_BRANCH}" != $TARGET_BRANCH ]]; then
         echo "Couldn't continue rebasing on ${TARGET_BRANCH}"
         exit 30  # Impossible to detect PRIMARY_BRANCH AND SECONDARY_BRANCH
     fi
 
-    SECONDARY_BRANCH=$1
-    PRIMARY_BRANCH=$2
-
     echo "Continuing rebasing of $SECONDARY_BRANCH on top of $PRIMARY_BRANCH"
     git commit || exit 51
     git branch -d "${SECONDARY_BRANCH}"  || exit 52