`cargo doc` no longer generates a nav list of all dependencies in the sidebar

[Evrey]

Since i don't know which version, when running cargo doc on a project, the left sidebar of the docs no longer has a nav for all crates in the dependency graph. However, the documentation for all dependencies is still compiled.

Steps to reproduce

1. Pick a Rust project with a few dependencies.
2. Run cargo doc --open
3. Expected: Left sidebar has a list of all dependencies, linking to each crate's local docs.
4. Got: No such thing.

Version it worked on

It most recently worked on: I honestly don't remember. I update my nightly before every dev session. Allegedly that bug is 27 days old.

Version with regression

rustc --version --verbose:

rustc 1.54.0-nightly (ca82264ec 2021-05-09)
binary: rustc
commit-hash: ca82264ec7556a6011b9d3f1b2fd4c7cd0bc8ae2
commit-date: 2021-05-09
host: x86_64-unknown-linux-gnu
release: 1.54.0-nightly
LLVM version: 12.0.1

[Nemo157]

Appears to be a regression from #84150, the call to addSidebarCrates was moved into initSidebarItems, but this function is not called on the crate-root doc page. I tested locally that it fails on nightly-2021-04-18 and works on nightly-2021-04-17.

[Nemo157]

Checking https://doc.rust-lang.org/beta/std/ it looks like this has made it onto the 1.53 beta.

[jyn514]

cc @jsha

[jsha]

I think the ideal fix is around

rust/src/librustdoc/html/render/mod.rs

Lines 1748 to 1753 in 1025db8

	if parentlen == 0 {
	// There is no sidebar-items.js beyond the crate root path
	// FIXME maybe dynamic crate loading can be merged here
	} else {
	write!(buffer, "<script defer src=\"{path}sidebar-items.js\"></script>", path = relpath);
	}

. We should emit a sidebar-items.js for the top page that just calls initSidebarItems({}). And remove that comment, since we now have dynamic crate loading.

A quicker fix is to just move the call to addSidebarCrates so it gets called independently from initSidebarItems. I like that less since the crates really are a sidebar item and should be treated as such.

[Stupremee]

I can do that if no one else wants to do it!