zoekt: treat repo names case sensitively

Created by: keegancsmith

Previously we treated zoekt repositories as if the case would not match what is returned from the repo database. However, Zoekt requires the correct caseing of the repo name to do the search. Additionally Zoekt uses the correct casing of the repo name when indexing.

So the uses of ToLower when checking if a repo was indexed was unnecessary. Additionally in the case a repository name changed case we would incorrectly believe we have indexed the repo, but the actual zoekt search would fail due to the index being case sensitive.

Additionally avoiding the calls to ToLower should improve performance. However, I didn't validate this (but naively it should).

Created by: keegancsmith

cc @tsenart @mrnugget if you remember our early work on zoekt perf, I think this was something we wanted to do? I spent a little bit of time validating we could :)

@sourcegraph/cloud note: we do ToLower on repo names in gitserver. This is unnecessary since we should always be using the casing from the repo table. This is a legacy from when gitserver used to be more directly tied to repo discovery. The proper solution some broader tech debt around using repo IDs everywhere instead of names.

Created by: codecov[bot]

Codecov Report

Merging #11670 into master will increase coverage by 0.08%. The diff coverage is 72.72%.

@@            Coverage Diff             @@
##           master   #11670      +/-   ##
==========================================
+ Coverage   47.44%   47.53%   +0.08%     
==========================================
  Files        1404     1402       -2     
  Lines       79706    79489     -217     
  Branches     6816     6775      -41     
==========================================
- Hits        37817    37782      -35     
+ Misses      38310    38131     -179     
+ Partials     3579     3576       -3     

Flag	Coverage Δ
#go	51.72% <72.72%> (+0.13%)
#storybook	10.12% <ø> (ø)
#typescript	36.42% <ø> (ø)
#unit	47.13% <72.72%> (+0.08%)

Impacted Files	Coverage Δ
cmd/frontend/graphqlbackend/repositories.go	37.65% <0.00%> (ø)
cmd/frontend/graphqlbackend/symbols.go	0.00% <0.00%> (ø)
internal/search/backend/text.go	0.00% <0.00%> (ø)
cmd/frontend/graphqlbackend/search_structural.go	56.52% <100.00%> (ø)
cmd/frontend/graphqlbackend/zoekt.go	72.07% <100.00%> (ø)
...cker-images/grafana/cmd/grafana-wrapper/grafana.go	0.00% <0.00%> (-4.00%)
.../internal/codeintel/resolvers/graphql/locations.go	78.30% <0.00%> (-3.78%)
docker-images/grafana/cmd/grafana-wrapper/main.go	0.00% <0.00%> (ø)
docker-images/grafana/cmd/grafana-wrapper/site.go	0.00% <0.00%> (ø)
...ages/grafana/cmd/grafana-wrapper/grafana_change.go
... and 2 more

Created by: keegancsmith

LGTM, but I'm surprised no tests had to be updated?

We didn't explicitly test the case insensitivity. I think if we did, we probably would of realised it didn't make sense to do given the queries themselves are case sensitive.