cmd/mod: replace package with tag already containing a '+' does not work with '+incompatible'

[sylr]

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

$ go version
go version go1.12.5 linux/amd64

Does this issue reproduce with the latest release?

Yes

What did you do?

Trying to compile https://github.com/improbable-eng/thanos with a dependency replacement, i.e.:

module github.com/improbable-eng/thanos

require (
        cloud.google.com/go v0.34.0
        github.com/Azure/azure-storage-blob-go v0.0.0-20181022225951-5152f14ace1c
        github.com/NYTimes/gziphandler v1.1.1
        github.com/armon/go-metrics v0.0.0-20180917152333-f0300d1749da
        github.com/fatih/structtag v1.0.0
        github.com/fortytw2/leaktest v1.3.0
        github.com/fsnotify/fsnotify v1.4.7
        github.com/go-kit/kit v0.8.0
        github.com/gogo/protobuf v1.2.1
        github.com/golang/snappy v0.0.1
        github.com/google/martian v2.1.0+incompatible // indirect
        github.com/googleapis/gax-go v2.0.2+incompatible // indirect
        github.com/gophercloud/gophercloud v0.0.0-20190301152420-fca40860790e
        github.com/grpc-ecosystem/go-grpc-middleware v1.0.0
        github.com/grpc-ecosystem/go-grpc-prometheus v0.0.0-20181025070259-68e3a13e4117
        github.com/hashicorp/go-sockaddr v1.0.2
        github.com/hashicorp/go-version v1.2.0
        github.com/hashicorp/golang-lru v0.5.1
        github.com/hashicorp/memberlist v0.1.3
        github.com/lovoo/gcloud-opentracing v0.3.0
        github.com/miekg/dns v1.1.8
        github.com/minio/minio-go v0.0.0-20190131015406-c8a261de75c1
        github.com/mozillazg/go-cos v0.12.0
        github.com/mwitkow/go-conntrack v0.0.0-20161129095857-cc309e4a2223
        github.com/oklog/run v1.0.0
        github.com/oklog/ulid v1.3.1
        github.com/olekukonko/tablewriter v0.0.1
        github.com/opentracing-contrib/go-stdlib v0.0.0-20170113013457-1de4cc2120e7
        github.com/opentracing/basictracer-go v1.0.0
        github.com/opentracing/opentracing-go v1.0.2
        github.com/pkg/errors v0.8.1
        github.com/prometheus/client_golang v0.9.3-0.20190127221311-3c4408c8b829
        github.com/prometheus/common v0.4.0
        github.com/prometheus/prometheus v2.9.2+incompatible
        github.com/prometheus/tsdb v0.7.2-0.20190507100016-6ac81cc7a9c5
        golang.org/x/net v0.0.0-20190311183353-d8887717615a
        golang.org/x/oauth2 v0.0.0-20190226205417-e64efc72b421
        golang.org/x/sync v0.0.0-20190227155943-e225da77a7e6
        golang.org/x/sys v0.0.0-20190322080309-f49334f85ddc // indirect
        golang.org/x/text v0.3.1-0.20180807135948-17ff2d5776d2
        google.golang.org/api v0.3.2
        google.golang.org/grpc v1.19.1
        gopkg.in/alecthomas/kingpin.v2 v2.2.6
        gopkg.in/fsnotify/fsnotify.v1 v1.4.7 // indirect
        gopkg.in/yaml.v2 v2.2.2
)

replace github.com/prometheus/prometheus => github.com/sylr/prometheus v2.9.2+sylr.2+incompatible

What did you expect to see?

What did you see instead?

sylvain@ubuntu-1604-dev:~/gopath/src/github.com/improbable-eng/thanos[prometheus-2.9.2]$ make build
go: finding github.com/sylr/prometheus v2.9.2+sylr.2+incompatible
go: errors parsing go.mod:
/home/sylvain/gopath/src/github.com/improbable-eng/thanos/go.mod:51: invalid module version github.com/sylr/prometheus: unknown revision v2.9.2+sylr.2+incompatible
Makefile:213: recipe for target 'go-mod-tidy' failed
make: *** [go-mod-tidy] Error 1

[bcmills]

We add the +incompatible suffix after resolving the tag to what we call a “canonical” semantic version string (that is, one without metadata). v2.9.2+sylr.2 is not canonical, so the go command doesn't know what to do with that suffix.

Due to the fix for #31713, v2.9.2+sylr.2 (without the +incompatible suffix) should work in Go 1.13.

[bcmills]

There is kind of a funny interaction with #27171 and #29262 here, though: we should resolve the tag to a pseudo-version starting with v2.9.2- and ending with +incompatible, but today we are resolving it to a pseudo-version with a v0.0.0- prefix.

$ go list -f '{{.Version}}' -m github.com/sylr/[email protected]+sylr.2
go: finding github.com/sylr/prometheus v2.9.2+sylr.2
v0.0.0-20190510132036-085fc219838d

[bcmills]

I've retitled #29262 to include this example. I think that makes this a duplicate of #31713 (which is fixed) and #29262 (which is not). Thanks for the report — this is an interesting example to consider.