Actually the builder offers a guarantee that the wall will be built to industry standards.
And to the exact specifications that were provided to him, in writing, at the time he bid for the job.
Try getting a builder to build the wall "just a bit higher" or "just a bit wider" or "just put a window in that patch you've finished already". Not going to happen.
Which is why programming is not the same as construction.
Indeed nobody would hire a builder who's contract stated that they offered no guarantee.
And, likewise, no builder would bit for a job that didn't have EVERYTHING already specified and signed off by a certified architect.
In software it is not possible in practice for someone to write a non-trivial program without any bugs.
The first problem in software is defining what a "bug" is. It's not a feature request. It's not something that was left out of the requirements.
If the employer can provide the same level of documentation for the program that a builder will be provided with then software "bugs" become a lot rarer.