Cicil law courts are bound to apply the law and certainly don't have the right to rewrite the law in most cases (the german constitutional court for example has the power to undo laws), but they still need to interpret the words of the law and the meaning of those words changes over time. For example the anti discrimination laws would as long as maybe 30 years ago never have encompassed discrimination for LGBTQ* people. The laws have not changes substantially, but the interpretation of those words has definitely changed and as such, rulings that were not possible then are standard now. Very often, rulings do have a law-like quality - even if strictly speaking, they are not laws. From the top of my head I can cite one example from the road laws in germany: There's a thing called "Bicylcle roads" and the legal scripture (Straßenverkehrsordnung) says that cars are required to maintain a "suitable speed." A single influential court decision pegged that to 30km/h about a decade or so ago - which has finally been fed back into the legal text this year.

So while strictly speaking, no court was bound to that decision, the decision was still referenced by many other court cases and became some sort of de-facto law.