Merge pull request #7 from stripe/carl-vendor

Work around GO15VENDOREXPERIMENT for Go 1.5

package15.go

@@ -0,0 +1,7 @@
+// +build !go1.6
+
+package main
+
+import "os"
+
+var useVendor = os.Getenv("GO15VENDOREXPERIMENT") == "1"

package16.go

@@ -0,0 +1,7 @@
+// +build go1.6
+
+package main
+
+import "os"
+
+var useVendor = os.Getenv("GO15VENDOREXPERIMENT") == "0" || os.Getenv("GO15VENDOREXPERIMENT") == ""

safesql.go

@@ -6,8 +6,11 @@ package main
 import (
 	"flag"
 	"fmt"
+	"go/build"
 	"go/types"
 	"os"
+	"path/filepath"
+	"strings"
 
 	"golang.org/x/tools/go/callgraph"
 	"golang.org/x/tools/go/loader"
@@ -32,7 +35,9 @@ func main() {
 		os.Exit(2)
 	}
 
-	c := loader.Config{}
+	c := loader.Config{
+		FindPackage: FindPackage,
+	}
 	c.Import("database/sql")
 	for _, pkg := range pkgs {
 		c.Import(pkg)
@@ -198,3 +203,46 @@ func FindNonConstCalls(cg *callgraph.Graph, qms []*QueryMethod) []ssa.CallInstru
 
 	return bad
 }
+
+// Deal with GO15VENDOREXPERIMENT
+func FindPackage(ctxt *build.Context, path, dir string, mode build.ImportMode) (*build.Package, error) {
+	if !useVendor {
+		return ctxt.Import(path, dir, mode)
+	}
+
+	// First, walk up the filesystem from dir looking for vendor directories
+	var vendorDir string
+	for tmp := dir; vendorDir == "" && tmp != "/"; tmp = filepath.Dir(tmp) {
+		dname := filepath.Join(tmp, "vendor", filepath.FromSlash(path))
+		fd, err := os.Open(dname)
+		if err != nil {
+			continue
+		}
+		// Directories are only valid if they contain at least one file
+		// with suffix ".go" (this also ensures that the file descriptor
+		// we have is in fact a directory)
+		names, err := fd.Readdirnames(-1)
+		if err != nil {
+			continue
+		}
+		for _, name := range names {
+			if strings.HasSuffix(name, ".go") {
+				vendorDir = filepath.ToSlash(dname)
+				break
+			}
+		}
+	}
+
+	if vendorDir != "" {
+		pkg, err := ctxt.ImportDir(vendorDir, mode)
+		if err != nil {
+			return nil, err
+		}
+		// Go tries to derive a valid import path for the package, but
+		// it's wrong (it includes "/vendor/"). Overwrite it here.
+		pkg.ImportPath = path
+		return pkg, nil
+	}
+
+	return ctxt.Import(path, dir, mode)
+}