Add -gopath flag to init

- Separate network mode and GOPATH mode of operations.
- In Network mode, do not check GOPATH or any ondisk projects. Solve the
dependency constraints completely over network.

Author: darkowlzz

cmd/dep/init.go

@@ -11,6 +11,7 @@ import (
 	"time"
 
 	"github.com/golang/dep"
+  fb "github.com/golang/dep/internal/feedback"
 	"github.com/golang/dep/internal/fs"
 	"github.com/golang/dep/internal/gps"
 	"github.com/golang/dep/internal/gps/paths"
@@ -30,14 +31,19 @@ disable this behavior. The following external tools are supported: glide.
 Any dependencies that are not constrained by external configuration use the
 GOPATH analysis below.
 
-The version of each dependency will reflect the current state of the GOPATH. If
-a dependency doesn't exist in the GOPATH, a version will be selected from the
-versions available from the upstream source per the following algorithm:
+By default, the dependencies are resolved over the network. A version will be
+selected from the versions available from the upstream source per the following
+algorithm:
 
  - Tags conforming to semver (sorted by semver rules)
  - Default branch(es) (sorted lexicographically)
  - Non-semver tags (sorted lexicographically)
 
+An alternate mode can be activated by passing -gopath. In this mode, the version
+of each dependency will reflect the current state of the GOPATH. If a dependency
+doesn't exist in the GOPATH, a version will be selected based on the above
+network version selection algorithm.
+
 A Gopkg.toml file will be written with inferred version constraints for all
 direct dependencies. Gopkg.lock will be written with precise versions, and
 vendor/ will be populated with the precise versions written to Gopkg.lock.
@@ -52,11 +58,13 @@ func (cmd *initCommand) Hidden() bool      { return false }
 func (cmd *initCommand) Register(fs *flag.FlagSet) {
 	fs.BoolVar(&cmd.noExamples, "no-examples", false, "don't include example in Gopkg.toml")
 	fs.BoolVar(&cmd.skipTools, "skip-tools", false, "skip importing configuration from other dependency managers")
+	fs.BoolVar(&cmd.gopath, "gopath", false, "search in GOPATH for dependencies")
 }
 
 type initCommand struct {
 	noExamples bool
 	skipTools  bool
+	gopath     bool
 }
 
 func (cmd *initCommand) Run(ctx *dep.Ctx, args []string) error {
@@ -119,10 +127,13 @@ func (cmd *initCommand) Run(ctx *dep.Ctx, args []string) error {
 	if err != nil {
 		return err
 	}
+
 	gs := newGopathScanner(ctx, directDeps, sm)
-	err = gs.InitializeRootManifestAndLock(m, l)
-	if err != nil {
-		return err
+	if cmd.gopath {
+		err = gs.InitializeRootManifestAndLock(m, l)
+		if err != nil {
+			return err
+		}
 	}
 
 	rootAnalyzer.skipTools = true // Don't import external config during solve for now
@@ -152,7 +163,20 @@ func (cmd *initCommand) Run(ctx *dep.Ctx, args []string) error {
 	l = dep.LockFromSolution(soln)
 
 	rootAnalyzer.FinalizeRootManifestAndLock(m, l)
-	gs.FinalizeRootManifestAndLock(m, l)
+	if cmd.gopath {
+		gs.FinalizeRootManifestAndLock(m, l)
+	} else {
+		// Pick the direct dependencies from the above solution and add to manifest
+		for _, x := range l.Projects() {
+			pr := x.Ident().ProjectRoot
+			if _, ok := directDeps[string(pr)]; ok {
+				m.Constraints[pr] = getProjectPropertiesFromVersion(x.Version())
+				feedback(x.Version(), pr, fb.DepTypeDirect, ctx.Err)
+			} else {
+				feedback(x.Version(), pr, fb.DepTypeTransitive, ctx.Err)
+			}
+		}
+	}
 
 	// Run gps.Prepare with appropriate constraint solutions from solve run
 	// to generate the final lock memo.

cmd/dep/testdata/harness_tests/init/case1/testcase.json

@@ -1,6 +1,6 @@
 {
   "commands": [
-    ["init", "-no-examples", "-skip-tools"]
+    ["init", "-no-examples", "-skip-tools", "-gopath"]
   ],
   "error-expected": "",
   "gopath-initial": {

cmd/dep/testdata/harness_tests/init/case2/testcase.json

@@ -1,6 +1,6 @@
 {
   "commands": [
-    ["init", "-no-examples", "-skip-tools"]
+    ["init", "-no-examples", "-skip-tools", "-gopath"]
   ],
   "error-expected": "",
   "gopath-initial": {

cmd/dep/testdata/harness_tests/init/case3/testcase.json

@@ -1,6 +1,6 @@
 {
   "commands": [
-    ["init", "-no-examples", "-skip-tools"]
+    ["init", "-no-examples", "-skip-tools", "-gopath"]
   ],
   "error-expected": "",
   "gopath-initial": {

cmd/dep/testdata/harness_tests/init/case4/final/Gopkg.lock

@@ -0,0 +1,8 @@
+
+[[constraint]]
+  name = "github.com/sdboyer/deptest"
+  version = "1.0.0"
+
+[[constraint]]
+  name = "github.com/sdboyer/deptestdos"
+  version = "2.0.0"

cmd/dep/testdata/harness_tests/init/case4/final/Gopkg.toml

@@ -0,0 +1,13 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package foo
+
+import "github.com/sdboyer/deptest"
+
+func Foo() deptest.Foo {
+	var y deptest.Foo
+
+	return y
+}

cmd/dep/testdata/harness_tests/init/case4/initial/foo/bar.go

@@ -0,0 +1,19 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+	"fmt"
+
+	"github.com/golang/notexist/foo"
+	"github.com/sdboyer/deptestdos"
+)
+
+func main() {
+	var x deptestdos.Bar
+	y := foo.FooFunc()
+
+	fmt.Println(x, y)
+}

cmd/dep/testdata/harness_tests/init/case4/initial/main.go

@@ -0,0 +1,12 @@
+{
+  "commands": [
+    ["init", "-no-examples"]
+  ],
+  "gopath-initial": {
+    "github.com/sdboyer/deptestdos": "a0196baa11ea047dd65037287451d36b861b00ea"
+  },
+  "vendor-final": [
+    "github.com/sdboyer/deptest",
+    "github.com/sdboyer/deptestdos"
+  ]
+}

cmd/dep/testdata/harness_tests/init/case4/testcase.json

@@ -1,6 +1,6 @@
 {
   "commands": [
-    ["init", "-no-examples", "-skip-tools"]
+    ["init", "-no-examples", "-skip-tools", "-gopath"]
   ],
   "error-expected": "",
   "gopath-initial": {