Stare decisis
to stand by things decided
Where the phrase comes from
The common-law practice that a court follows its earlier holdings, and lower courts follow higher ones, so people can order their affairs.
What lawyers are pointing at
The doctrine is about the holding, not about every paragraph in an old opinion. Courts do depart from prior holdings, and when they do the honest form is to say so and give the reason. A system that silently decides the same facts the other way is not flexible. It is unpredictable. Stare decisis is a discipline of change, not a ban on change.
The same shape in code
A regression test is a small holding. If the test encoded a bug, change the test in the same commit that changes the behavior, and say why the old holding was wrong. Editing the assertion with no note is overturning a case in a locked room.
A concrete picture
A court held last year that this kind of notice clause is valid. A later judge with the same facts does not get to ignore that holding because today's result would be nicer. The path is to follow it or to overrule it in the open.