rustdoc referenced `search.js` and `settings.js` not via `static-root-path`

[syphar]

• there was a bug in rustdoc where a toolchain specific static asset (search.js) wasn't referenced via static-root-path, but via the path for release (invocation) specific assets. ( introduced in rustdoc: Consolidate static-file replacement mechanism rust#91062 ).
• this was fixed with rustdoc: add hash to filename of toolchain files rust#101702, so all docs built after that are correct.
• our LegacySharedResourcesHandler which was a hack for Docs built during 2018-{10-12} link to the wrong url for static resources #1181 also worked for this bug, so this was never visible to users.
• after the rebuild for Docs built during 2018-{10-12} link to the wrong url for static resources #1181 was finished we dropped the LegacySharedResourcesHandler with the last piece of the axum migration (migrate the main rustdoc handlers to axum, drop iron #1963).
• we added a new workaround in refs #1979: add workaround for toolchain JS files that were referenced wrong #1980 which only handles search.js, and only at the specific location it might be requested.
• we added another workaround in refs #1979, #1992: workaround for settings.js not served from the root #1993 to also handle settings.js, same as to refs #1979: add workaround for toolchain JS files that were referenced wrong #1980
• to remove the workaround, we need to rebuild the affected releases.

initial issue

• This was initially reported as "broken search" after migrate the main rustdoc handlers to axum, drop iron #1963 was merged.
• broken settings were reported in Broken settings on crossbeam-0.8.2 #1992

reported broken releases:

• search: https://docs.rs/mipidsi/latest/mipidsi/index.html?search=init (released 2022-10-19)
• search: https://docs.rs/js-sys/latest/js_sys/index.html?search=Array (released 2022-09-12)
• search: https://docs.rs/diesel/latest/diesel/?search=tosql (released 2022-10-11)
• settings: https://docs.rs/crossbeam/0.8.2/crossbeam/channel/index.html (released 2022-07-22)

reported via:

• https://www.reddit.com/r/rust/comments/zx1j8a/is_search_broken_on_docsrs/
• https://rust-lang.zulipchat.com/#narrow/stream/356853-t-docs-rs/topic/search.20broken.20for.20some.20crates.3F

[syphar]

interestingly I found that

• this release is broken: https://docs.rs/regex/1.7.0/regex/index.html?search=test (released 2022-11-05)
• while accessing it via /latest/ works: https://docs.rs/regex/latest/regex/index.html?search=test
  Probably

the latter seems to be served from the cache

[syphar]

there are also working releases, via version and /latest/:

• https://docs.rs/itertools/0.10.5/itertools/index.html?search=chain
• https://docs.rs/itertools/latest/itertools/index.html?search=chain
  ( released 2022-09-20)

[syphar]

the JS file that gets requested:
https://docs.rs/regex/1.7.0/search-20221104-1.67.0-nightly-09508489e.js

is actually not invocation specific, but toolchain specific. I can also find it in our bucket in the root directory.

It is still requested from the release specific path, and not from the given static-root-path.

[syphar]

This feels like a bug in rustdoc, while our LegacySharedResourcesHandler previously hid this issue because it checked all static file requests with the bucket root

[syphar]

as a workaround I'll probably add back checking the toolchain specific files for this case, pending a fix in rustdoc (and then potentially a rebuild?)

[syphar]

To sum up the discussion on zulip ( topic link in issue description):

• there was a bug in rustdoc where a toolchain specific static asset wasn't referenced via static-root-path, but via the path for release (invocation) specific assets. ( rustdoc: Consolidate static-file replacement mechanism rust#91062 ).
• this was fixed in rustdoc: add hash to filename of toolchain files rust#101702, so all docs built after that are correct.
• our LegacySharedResourcesHandler which was a hack for Docs built during 2018-{10-12} link to the wrong url for static resources #1181 also worked for this bug, so this was never visible to users.
• after the rebuild for Docs built during 2018-{10-12} link to the wrong url for static resources #1181 was finished I dropped the LegacySharedResourcesHandler with the last piece of the axum migration (migrate the main rustdoc handlers to axum, drop iron #1963).

[syphar]

The fix (= hack) for this is to partially re-introduce this behaviour, pending another rebuild of the broken docs.