x/tools/gopls: slow completions from github.com/aws/aws-sdk-go/service/ec2

[heschi]

Completing out of the ec2 package is horribly slow, apparently because astutil.PathEnclosingInterval doesn't scale. We could add indexes, or stop returning results after the first few hundred.

@muirdm @stamblerre

[bmurphy1976]

Awesome! I was just coming here to report the same thing (although with much less detail). I thought my VSCode intellisense was broken, but after debugging it I came to find it was simply taking 12 seconds to load the data for the ec2.EC2 type:

[Trace - 17:04:53.416 PM] Received response 'textDocument/completion - (16)' in 12041ms.

[gopherbot]

Change https://golang.org/cl/221021 mentions this issue: internal/lsp/source: speed up completion candidate formatting

[muirdm]

The proof-of-concept CL above helps a lot, but it is still too slow if you have completion documentation enabled. We can probably speed that up too using the same cache-types.Object-to-ast.Node approach, but I want to hear what others think.

[mlieberman85]

Is there anything that can be done from a gopls config level while https://golang.org/cl/221021 is being worked on for gopls to ignore problematic packages like ec2?

[stamblerre]

I don't think that will be possible, sorry about that, @mlieberman85. We'll aim to get the fix out in gopls/v0.5.0, and I think that #38278 will be the ultimate fix for this issue.