x/tools/cmd/godoc: url flag races against index creation

[rhysh]

What version of Go are you using (go version)?

$ go version
go version devel +701f6a27b5 Mon Feb 11 18:18:45 2019 +0000 darwin/amd64

I'm comparing the x/tools repo at release-branch.go1.11 vs release-branch.go1.12.

Does this issue reproduce with the latest release?

Yes, this is broken in master of the x/tools repo.

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/rhys/Library/Caches/go-build"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOOS="darwin"
GOPATH="/Users/rhys/go"
GOPROXY=""
GORACE=""
GOROOT="/usr/local/go"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/darwin_amd64"
GCCGO="gccgo"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/49/zmds5zsn75z1283vtzxyfr5hj7yjq4/T/go-build329945537=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

go run golang.org/x/tools/cmd/godoc -url=/pkg/fmt -http=""
2019/02/15 10:34:12 HTTP error 404
exit status 1

What did you expect to see?

I expected to see HTML similar to what's served by https://golang.org/pkg/fmt/

What did you see instead?

I got an error message referencing an HTTP 404 code. It appears that the request to satisfy the url flag races against the index creation, so no packages are found.

---

I have a fix for this, including regression tests. I'll upload it shortly.

[gopherbot]

Change https://golang.org/cl/162907 mentions this issue: cmd/godoc: fix -url flag, add tests

[dmitshur]

This is a regression from CL 141397, where the logic for whether to init corpus synchronously was modified. It was partially fixed for writing index mode in CL 141717, but not for url flag mode. It wasn't caught because we didn't have a test for the -url flag yet (we will after your CL, thanks for that).