Comment by kouteiheika

> but this idea that dependency count is the issue is misguided

Well, partially you're right. There are roughly two things which are important here:

1) The number of unique authors/entities controlling the dependencies. (So 10 crates by exactly same author would still count as one dependency.)

2) The amount of code pulled in by a crate. (Because this tanks your compile times; I've seen projects pulling in hundreds of thousands of lines of code in external dependencies and using less that 1% of that, and then people make surprised pikachu face that Rust is slow to compile.)

> I don't have access to the closed-source repo to run `cargo tree` to see where `unindent` is used from, but why do you feel this is an invalid crate to pull in? It is a proc-macro, that deindents string literals at compile time. Would I include it directly in a project of mine? Likely not, but if I were using `indoc` (written by dtolnay), which uses `unindent` (written by dtolnay) my reaction wouldn't be "oh, no! An additional useless dependency!".

I would never include either in any of my projects, and would veto any attempt to do so. As I already said, the 'unindent' crate is trivial to write by myself, and the 'indoc' crate seems completely not worth it from a cost/benefit standpoint in the very rare case I'd need something like that (it's easy enough to make do without it, as it's just a minor situational quality of life crate).

In general my policy on external dependencies is stricter than most people; I usually only include high value/high impact dependencies, and I try to evaluate whether a given dependency is appropriate in context of the concrete project I want to use it in. If it's a throwaway script that I need to run once and won't really maintain long-term - I go crazy with gluing whatever external crates there are just to get it done ASAP! But if it's a project that I'll need to maintain over a long period of time I get a lot more strict, and if it's a library that I expect other people to use then the bar for external dependencies gets even higher (because any extra dependency I add will bloat up the compile times and the dependency trees of any downstream users).

I also find it helpful to ask myself the question - if it wasn't easy to add new dependencies (e.g. if I was still writing in C++, or cargo wasn't a thing) would I still include this dependency in my project? If the answer is "no" then maybe it's better not to.

There are some notable exceptions, but sadly most of the Rust community doesn't do things this way.