modules: Set GOCACHE env var

This was introduced in Go 1.15. We do set the GOPATH, which should be enough, but #9309 indicate that's not the case on every platform (GitHub Actions).

Closes #9309

diff --git a/modules/client.go b/modules/client.go
index 1924cd5b4c6181495721168ca391bd719bbc8126..5b61e5644329938a1759f71a79c3202954811548 100644 (file)
--- a/modules/client.go
+++ b/modules/client.go
@@ -90,6 +90,8 @@ func NewClient(cfg ClientConfig) *Client {
                "GOPRIVATE", mcfg.Private,
                "GONOPROXY", mcfg.NoProxy,
                "GOPATH", cfg.CacheDir,
+               // GOCACHE was introduced in Go 1.15. This matches the location derived from GOPATH above.
+               "GOCACHE", filepath.Join(cfg.CacheDir, "pkg", "mod"),
        )
 
        logger := cfg.Logger