找到新的 Jmeter 板测试碎片：

#!watchflakes
default <- pkg == "cmd/go" && test == "TestScript/mod_get_fallback"

2024-01-31 20:51 gotip-linux-amd64-longtest-race go@5c0d0929 cmd/go.TestScript/mod_get_fallback ( log )

=== RUN   TestScript/mod_get_fallback
=== PAUSE TestScript/mod_get_fallback
=== CONT  TestScript/mod_get_fallback
    script_test.go:132: 2024-01-31T21:07:29Z
    script_test.go:134: $WORK=/home/swarming/.swarming/w/ir/x/t/cmd-go-test-2626998490/tmpdir2658682677/mod_get_fallback3284986218
    script_test.go:156: 
        PATH=/home/swarming/.swarming/w/ir/x/t/cmd-go-test-2626998490/tmpdir2658682677/testbin:/home/swarming/.swarming/w/ir/x/w/goroot/bin:/home/swarming/.swarming/w/ir/x/w/goroot/bin:/home/swarming/.swarming/w/ir/x/w/goroot/bin:/home/swarming/.swarming/w/ir/cache/tools/bin:/home/swarming/.swarming/w/ir/bbagent_utility_packages:/home/swarming/.swarming/w/ir/bbagent_utility_packages/bin:/home/swarming/.swarming/w/ir/cipd_bin_packages:/home/swarming/.swarming/w/ir/cipd_bin_packages/bin:/home/swarming/.swarming/w/ir/cipd_bin_packages/cpython3:/home/swarming/.swarming/w/ir/cipd_bin_packages/cpython3/bin:/home/swarming/.swarming/w/ir/cache/cipd_client:/home/swarming/.swarming/w/ir/cache/cipd_client/bin:/home/swarming/.swarming/cipd_cache/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
        HOME=/no-home
        CCACHE_DISABLE=1
        GOARCH=amd64
...
        # get https://proxy.golang.org/golang.org/x/mod/@v/v0.14.0.info
        # get https://proxy.golang.org/golang.org/x/mod/@v/v0.14.0.info: 200 OK (0.002s)
        go: added golang.org/x/mod v0.14.0
        go: added golang.org/x/tools v0.17.0
        > stderr '# get https://proxy.golang.org/golang.org/x/tools/@v/list'
        matched: # get https://proxy.golang.org/golang.org/x/tools/@v/list
        > ! stderr '# get https://golang.org'
        matched: # get https://golang.org/x/tools/cmd?go-get=1
    script_test.go:156: FAIL: testdata/script/mod_get_fallback.txt:11: stderr '# get https://golang.org': unexpected success
--- FAIL: TestScript/mod_get_fallback (73.98s)

— watchflakes

找到新的 Jmeter 板测试碎片：

#!watchflakes
default <- pkg == "cmd/go" && test ~ `TestScript` && `FAIL: TestScript/mod_get_fallback`

2024-02-02 15:13 linux-amd64-longtest-race go@244ccf47 cmd/go.TestScript ( log )

vcs-test.golang.org rerouted to http://127.0.0.1:38655
https://vcs-test.golang.org rerouted to https://127.0.0.1:36249
go test proxy running at GOPROXY=http://127.0.0.1:33443/mod
2024/02/02 16:03:19 http: TLS handshake error from 127.0.0.1:34554: read tcp 127.0.0.1:36249->127.0.0.1:34554: read: connection reset by peer
2024/02/02 16:03:19 http: TLS handshake error from 127.0.0.1:34548: EOF
2024/02/02 16:03:19 http: TLS handshake error from 127.0.0.1:34528: EOF
--- FAIL: TestScript (1.11s)
    --- FAIL: TestScript/mod_get_fallback (66.99s)
        script_test.go:132: 2024-02-02T16:03:51Z
        script_test.go:134: $WORK=/workdir/tmp/cmd-go-test-687207055/tmpdir1040938466/mod_get_fallback3961943255
...
            # get https://proxy.golang.org/golang.org/x/mod/@v/list: 200 OK (0.010s)
            # get https://proxy.golang.org/golang.org/x/mod/@v/v0.14.0.info
            # get https://proxy.golang.org/golang.org/x/mod/@v/v0.14.0.info: 200 OK (0.003s)
            go: added golang.org/x/mod v0.14.0
            go: added golang.org/x/tools v0.17.0
            > stderr '# get https://proxy.golang.org/golang.org/x/tools/@v/list'
            matched: # get https://proxy.golang.org/golang.org/x/tools/@v/list
            > ! stderr '# get https://golang.org'
            matched: # get https://golang.org/x?go-get=1
        script_test.go:156: FAIL: testdata/script/mod_get_fallback.txt:11: stderr '# get https://golang.org': unexpected success

— watchflakes

这里的根本原因似乎是 x/tools 模块的模块代理产生了一个错误的 404 响应。从测试日志中可以看到：

https://proxy.golang.org/golang.org/x/tools/@v/list: 404 Not Found (58.250s)

(仅供参考 @suzmue)