Wikipedia
In computer programming jargon, lava flow is a problem in which computer code written under sub-optimal conditions is put into production and added to while still in a developmental state. Often, putting the system into production results in a need to maintain backward compatibility (as many additional components now depend on it) with the original, incomplete design.
Changes in the development team working on a project often exacerbate lava flows. As workers cycle in and out of the project, knowledge of the purpose of aspects of the system can be lost. Rather than clean up these pieces, subsequent workers work around them, increasing the complexity and mess of the system.
Lava flow is considered an anti-pattern, a commonly encountered phenomenon leading to poor design.
Usage examples of "lava flow".
Oh there were a few low boulder hermitages on rim overlooks, and a piste had been built on the northeast lava flow that broke the escarpment ring surrounding the volcano, for easy access to the festival complex at Crater Zp.
They hadn't even divided up to search for the track when they reached the edge of the lava flow.
So the spring would be near a lava flow, and the cave itself was probably a lava tube.
It froze out of a lava flow, that bubbled out of the Moon more than three billion years ago.
Then the Squam parked as close to the hot-lava flow as possible, and used his pincers to string the linked cables over the dome, catching them in a crevice so they would not slip off side-wise.
A lava flow had passed this way some years back, come down out of Killeshan's maw to sweep the crest of Blackledge clean.
This island was a sharp slab that thrust up through the lava flow at such a steep angle that they had to circle nearly all the way around it before they found a place where they could climb.