x/tools/gopls/internal/regtest/modfile: TestSumUpdateFixesDiagnostics failures with "Unmet: empty diagnostics"

[bcmills]

--- FAIL: TestSumUpdateFixesDiagnostics (544.64s)
    --- FAIL: TestSumUpdateFixesDiagnostics/experimental (543.87s)
        modfile_test.go:842: waiting on:
            	Unmet: empty diagnostics for "go.mod"
            
            err:context deadline exceeded
            
            state:
            #### log messages (see RPC logs for full text):
            	Info: "2022/02/24 04:27:21 go env for /tmp/workdir-host-l...
            	Error: "2022/02/24 04:27:21 go/packages.Load: err: exit s...
            	Error: "2022/02/24 04:27:21 initial workspace load failed...
            	Error: "2022/02/24 04:27:21 errors loading workspace: err...
            	Error: "2022/02/24 04:27:21 workspace packages: diagnosin...
            	Error: "2022/02/24 04:27:21 workspace packages: diagnosin...
            	Error: "2022/02/24 04:27:21 workspace packages: diagnosin...
            	Error: "2022/02/24 04:27:21 errors loading workspace: err...
            	Error: "2022/02/24 04:27:21 workspace packages: diagnosin...
            	Error: "2022/02/24 04:27:21 errors loading workspace: err...
            	Error: "2022/02/24 04:27:22 workspace packages: diagnosin...
            	Error: "2022/02/24 04:27:22 go/packages.Load: err: exit s...
            	Error: "2022/02/24 04:27:22 initial workspace load failed...
            	Error: "2022/02/24 04:27:22 workspace packages: diagnosin...
            	Error: "2022/02/24 04:27:22 errors loading workspace: err...
            	Error: "2022/02/24 04:27:22 go/packages.Load: err: exit s...
            	Error: "2022/02/24 04:27:22 initial workspace load failed...
            	Error: "2022/02/24 04:27:22 errors loading workspace: err...
            	Error: "2022/02/24 04:27:22 workspace packages: diagnosin...
            
            #### diagnostics:
            	go.mod (version 2):
            		(4, 0): go.sum is out of sync with go.mod: entry for example.com@v1.2.3 is missing. Please updating it by applying the quick fix.
            
            #### outstanding work:
            	Error loading workspace: 0.00
            #### completed work:
            	Running go mod tidy: 1
            	diagnosing opened files: 1
            	diagnosing changed files: 1
            	Updating go.sum: 1
            	diagnosing files changed on disk: 2
            	diagnosing saved files: 1
            	Load: 4
            	Setting up workspace: 1
            	diagnosing initial workspace load: 1
        runner.go:324: closing editor: Shutdown: context deadline exceeded
FAIL
FAIL	golang.org/x/tools/gopls/internal/regtest/modfile	578.270s

greplogs --dashboard -md -l -e 'FAIL: TestSumUpdateFixesDiagnostics .*(?:\n .*)*Unmet: empty diagnostics' --since=2022-02-02

2022-02-23T19:46:34-258e473-e534907/linux-amd64-wsl
2022-02-17T17:37:50-a317113-eaf0405/linux-amd64-wsl
2022-02-16T18:05:27-11109f6-a289e9c/linux-amd64-wsl

CC @findleyr @mengzhuo

[bcmills]

One notable thing about this builder is that its connection to proxy.golang.org is unreliable (see #42971).

I wonder if TestSumUpdateFixesDiagnostics is somehow failing to notice and propagate a failure to apply the fix due to a bad connection to the proxy. 🤔

[bcmills]

This does not appear to be specific to the -wsl builder.

greplogs --dashboard -md -l -e 'FAIL: TestSumUpdateFixesDiagnostics .*(?:\n .*)*Unmet: empty diagnostics' --since=2022-02-25

2022-04-03T23:48:16-153e30b-ba6df85/windows-arm64-11
2022-04-02T14:28:33-153e30b-8a816d5/linux-amd64-longtest

[bcmills]

greplogs --dashboard -md -l -e 'FAIL: TestSumUpdateFixesDiagnostics .*(?:\n .*)*Unmet: empty diagnostics' --since=2022-04-04

2022-04-06T18:19:46-6731659-5bb2628/linux-amd64-wsl

[gopherbot]

Change https://go.dev/cl/398699 mentions this issue: gopls/internal/regtest/modfile: temporarily skip TestSumUpdateFixesDiagnostics