The mistake the programmer has made is copy-pasting a line that wasn't meant to be copy-pasted. The error is gobbledegook about implementation details of the deps file, saying a map is malformed in a file that has 5x maps and not much more to bring in 2 dependencies. The error message itself isn't the problem as much as the spartan design of the deps file that leads rookies into screwing up in a way that isn't obvious what went wrong. There are a lot of easy syntax errors here that give no useful error message explaining what went wrong. There isn't even a hint how many maps are needed to bring in those 2 dependencies (turns out, 4). It'll bleed newbies if they try to figure out this file.
I think their should be a "lein-for-deps-template" that subtly guides people in the right direction by starting the project up with 2+ dependencies. Lein dodges this by using a list-of-list data structure where this mistake is harder to make (copy and pasting stuff in brackets is the right strategy in lein) and there is much more boilerplate in a project.clj to hint what our aspiring Clojure programmer needs to fill in.
My problem here is that the entire way through that story, at no point is there a simple prompt in the official reference documentation telling people what a deps file with multiple dependencies should look like. Even finding the examples of 1 dependency is quite deep in and seems to be an advanced topic (you'll note the sibling comment that considers dependencies an advanced topic for people who already know the language well enough to reflexively get maps right, and it says a lot about the actual complexity of deps that the official guide to installing dependencies thinks 2x dependencies is out of its scope).
I think their should be a "lein-for-deps-template" that subtly guides people in the right direction by starting the project up with 2+ dependencies. Lein dodges this by using a list-of-list data structure where this mistake is harder to make (copy and pasting stuff in brackets is the right strategy in lein) and there is much more boilerplate in a project.clj to hint what our aspiring Clojure programmer needs to fill in.
My problem here is that the entire way through that story, at no point is there a simple prompt in the official reference documentation telling people what a deps file with multiple dependencies should look like. Even finding the examples of 1 dependency is quite deep in and seems to be an advanced topic (you'll note the sibling comment that considers dependencies an advanced topic for people who already know the language well enough to reflexively get maps right, and it says a lot about the actual complexity of deps that the official guide to installing dependencies thinks 2x dependencies is out of its scope).