Xjyuk

How can I refer to something that barely work given a certain context and can get broken at any moment?

The thing is I wrote some geometry calculations in an application that will work in our context but any minimum condition can make it fail.

So I typed in the commit :

".. there are precision issues and different contexts that make this algorithm [some idiom or word for something barely functional]..."

How about brittle?

1a : easily broken, cracked, or snapped
_{definition from m-w.com}

From the "choose the right synonym" section, Merriam-Webster also says:

Fragile, frangible, brittle mean breaking easily. Fragile implies extreme delicacy of material or construction and need for careful handling. Frangible implies susceptibility to being broken without implying weakness or delicacy. Brittle implies hardness together with lack of elasticity or flexibility or toughness.

Adding on to M-W's description, my understanding is that fragile implies that "ordinary handling" (e.g. just picking something up in a casual manner) is likely to cause damage or breakage, while brittle is generally okay with ordinary handling but anything beyond that (e.g. setting it down hard, bumping it) will likely cause damage.

So, if you consider "within your context" to be "ordinary handling", your algorithm works fine here; but trying to apply it to anything outside of that context is likely to cause a problem. Thus you could use "brittle" to describe it.

"unreliable" seems like a good fit.

".. there are precision issues and different contexts that make this algorithm unreliable."

• unreliable - "not able to be trusted to do or provide what is needed or promised" MW




• If you describe a person, machine, or method as unreliable, you mean that you cannot trust them.
  
  e.g. He had an unreliable car. Collins

Temperamental is often used this way in a colloquial context. https://www.macmillandictionary.com/us/dictionary/american/temperamental

I would say "… makes this algorithm precarious"
Precarious: 1) not securely held or in position; dangerously likely to fall or collapse 2) dependent on chance; uncertain