cmd/api: update run.go to fetch from go.tools when needed

R=gri
CC=golang-dev
https://golang.org/cl/12639043

diff --git a/src/cmd/api/run.go b/src/cmd/api/run.go
index 8137b23429dbb2fc943c32c2a358b796cda0b223..f17d5eac9dc2b14e46afb4681aa53a6495bf6af0 100644 (file)
--- a/src/cmd/api/run.go
+++ b/src/cmd/api/run.go
@@ -22,6 +22,11 @@ import (
        "strconv"
 )
 
+// goToolsVersion is the hg revision of the go.tools subrepo we need
+// to build cmd/api.  This only needs to be updated whenever a go/types
+// bug fix is needed by the cmd/api tool.
+const goToolsVersion = "6698ca2900e2"
+
 var goroot string
 
 func main() {
@@ -36,10 +41,15 @@ func main() {
                return
        }
 
-       out, err := exec.Command("go", "install", "--tags=api_tool", "cmd/api").CombinedOutput()
+       gopath := prepGoPath()
+
+       cmd := exec.Command("go", "install", "--tags=api_tool", "cmd/api")
+       cmd.Env = append([]string{"GOPATH=" + gopath}, os.Environ()...)
+       out, err := cmd.CombinedOutput()
        if err != nil {
                log.Fatalf("Error installing cmd/api: %v\n%s", err, out)
        }
+
        out, err = exec.Command("go", "tool", "api",
                "-c", file("go1", "go1.1"),
                "-next", file("next"),
@@ -63,3 +73,45 @@ func forceAPICheck() bool {
        v, _ := strconv.ParseBool(os.Getenv("GO_FORCE_API_CHECK"))
        return v
 }
+
+// prepGoPath returns a GOPATH for the "go" tool to compile the API tool with.
+// It tries to re-use a go.tools checkout from a previous run if possible,
+// else it hg clones it.
+func prepGoPath() string {
+       const tempBase = "go.tools.TMP"
+
+       // The GOPATH we'll return
+       gopath := filepath.Join(os.TempDir(), "gopath-api", goToolsVersion)
+
+       // cloneDir is where we run "hg clone".
+       cloneDir := filepath.Join(gopath, "src", "code.google.com", "p")
+
+       // The dir we clone into. We only atomically rename it to finalDir on
+       // clone success.
+       tmpDir := filepath.Join(cloneDir, tempBase)
+
+       // finalDir is where the checkout will live once it's complete.
+       // If this exists already, we're done.
+       finalDir := filepath.Join(cloneDir, "go.tools")
+
+       if fi, err := os.Stat(finalDir); err == nil && fi.IsDir() {
+               return gopath
+       }
+
+       if err := os.MkdirAll(cloneDir, 0700); err != nil {
+               log.Fatal(err)
+       }
+       cmd := exec.Command("hg",
+               "clone", "--rev="+goToolsVersion,
+               "https://code.google.com/p/go.tools",
+               tempBase)
+       cmd.Dir = cloneDir
+       out, err := cmd.CombinedOutput()
+       if err != nil {
+               log.Fatalf("Error running hg clone on go.tools: %v\n%s", err, out)
+       }
+       if err := os.Rename(tmpDir, finalDir); err != nil {
+               log.Fatal(err)
+       }
+       return gopath
+}