Both grep and greplace! use "heisenparameters"

[pmonks]

As articulated by Stuart Sierra, the use of function parameters that may either be collections or singletons is an anti-pattern, yet that's exactly how grep and greplace! are implemented, for exactly the reason the article decries (convenience).

Although the fix is technically trivial, it does break backwards compatibility, so this will require some research to try to identify downstream users of the library, and then outreach to those projects' maintainers to ask them whether this fix is worth the pain it will inflict on them.

[pmonks]

With the demise of crossclj, I'm not sure how to identify downstream consumers of the library. If anyone knows of other tools or sites that provide this kind of information, it would be most welcome!

[pmonks]

I threw together a little tool that allows one to determine this, at least for projects hosted on Clojars.

Running clj -i repl-init.clj -r drops us in a pre-populated REPL, where we can run:

user=> (get inverted-dependencies "clj-commons/multigrep")
nil
user=> (get inverted-dependencies "org.clojars.pmonks/multigrep")
[["org.alfrescolabs.alfresco-technical-validation/org.alfrescolabs.alfresco-technical-validation" "org.clojars.pmonks/multigrep"]]

i.e. there's only one Clojars-hosted project that's using this library.