Add -gopath flag to init

- Separate network mode and GOPATH mode of operations.
- In GOPATH mode, fetch projectData by searching through the current
GOPATH. Solve the dependency constraints based on the projects found on
disk and use network to solve for projects not found on disk.
- In Network mode, do not check GOPATH or any ondisk projects. Solve the
dependency constraints completely over network.

cmd/dep/init.go

@@ -27,14 +27,19 @@ Initialize the project at filepath root by parsing its dependencies, writing
 manifest and lock files, and vendoring the dependencies. If root isn't
 specified, use the current directory.
 
-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, 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.
@@ -48,10 +53,12 @@ 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.gopath, "gopath", false, "search in GOPATH for dependencies")
 }
 
 type initCommand struct {
 	noExamples bool
+	gopath     bool
 }
 
 func trimPathPrefix(p1, p2 string) string {
@@ -115,44 +122,56 @@ func (cmd *initCommand) Run(ctx *dep.Ctx, args []string) error {
 	sm.UseDefaultSignalHandling()
 	defer sm.Release()
 
-	ctx.Loggers.Err.Println("Searching GOPATH for projects...")
-	pd, err := getProjectData(ctx, pkgT, cpr, sm)
-	if err != nil {
-		return err
-	}
+	// Create empty manifest, lock and projectData, and fill them according to
+	// init operation modes. If gopath flag is set, fetch projectData by searching
+	// through GOPATH, else operate in network mode, solve all the dependencies
+	// over network.
 	m := &dep.Manifest{
-		Dependencies: pd.constraints,
+		Dependencies: make(gps.ProjectConstraints),
 	}
+	l := &dep.Lock{}
+	var pd projectData
 
-	// Make an initial lock from what knowledge we've collected about the
-	// versions on disk
-	l := &dep.Lock{
-		P: make([]gps.LockedProject, 0, len(pd.ondisk)),
-	}
+	if cmd.gopath {
+		ctx.Loggers.Err.Println("Searching GOPATH for projects...")
+		pd, err = getProjectData(ctx, pkgT, cpr, sm)
+		if err != nil {
+			return err
+		}
 
-	for pr, v := range pd.ondisk {
-		// That we have to chop off these path prefixes is a symptom of
-		// a problem in gps itself
-		pkgs := make([]string, 0, len(pd.dependencies[pr]))
-		prslash := string(pr) + "/"
-		for _, pkg := range pd.dependencies[pr] {
-			if pkg == string(pr) {
-				pkgs = append(pkgs, ".")
-			} else {
-				pkgs = append(pkgs, trimPathPrefix(pkg, prslash))
+		m.Dependencies = pd.constraints
+
+		// Make an initial lock from what knowledge we've collected about the
+		// versions on disk
+		l = &dep.Lock{
+			P: make([]gps.LockedProject, 0, len(pd.ondisk)),
+		}
+
+		for pr, v := range pd.ondisk {
+			// That we have to chop off these path prefixes is a symptom of
+			// a problem in gps itself
+			pkgs := make([]string, 0, len(pd.dependencies[pr]))
+			prslash := string(pr) + "/"
+			for _, pkg := range pd.dependencies[pr] {
+				if pkg == string(pr) {
+					pkgs = append(pkgs, ".")
+				} else {
+					pkgs = append(pkgs, trimPathPrefix(pkg, prslash))
+				}
 			}
+
+			l.P = append(l.P, gps.NewLockedProject(
+				gps.ProjectIdentifier{ProjectRoot: pr}, v, pkgs),
+			)
 		}
 
-		l.P = append(l.P, gps.NewLockedProject(
-			gps.ProjectIdentifier{ProjectRoot: pr}, v, pkgs),
-		)
+		ctx.Loggers.Err.Println("Using network for remaining projects...")
 	}
 
-	ctx.Loggers.Err.Println("Using network for remaining projects...")
 	// Copy lock before solving. Use this to separate new lock projects from soln
 	copyLock := *l
 
-	// Run solver with project versions found on disk
+	// Run solver with the available knowledge to solve the dependency constraints
 	if ctx.Loggers.Verbose {
 		ctx.Loggers.Err.Println("dep: Solving...")
 	}
@@ -180,25 +199,43 @@ func (cmd *initCommand) Run(ctx *dep.Ctx, args []string) error {
 	}
 	l = dep.LockFromInterface(soln)
 
-	// Iterate through the new projects in solved lock and add them to manifest
-	// if direct deps and log feedback for all the new projects.
-	for _, x := range l.Projects() {
-		pr := x.Ident().ProjectRoot
-		newProject := true
-		// Check if it's a new project, not in the old lock
-		for _, y := range copyLock.Projects() {
-			if pr == y.Ident().ProjectRoot {
-				newProject = false
+	// Populate manifest based on operation mode.
+	if cmd.gopath {
+		// Iterate through the new projects in solved lock and add them to manifest
+		// if direct deps and log feedback for all the new projects.
+		for _, x := range l.Projects() {
+			pr := x.Ident().ProjectRoot
+			newProject := true
+			// Check if it's a new project, not in the old lock
+			for _, y := range copyLock.Projects() {
+				if pr == y.Ident().ProjectRoot {
+					newProject = false
+				}
+			}
+			if newProject {
+				// Check if it's in notondisk project map. These are direct deps, should
+				// be added to manifest.
+				if _, ok := pd.notondisk[pr]; ok {
+					m.Dependencies[pr] = getProjectPropertiesFromVersion(x.Version())
+					feedback(x.Version(), pr, fb.DepTypeDirect, ctx)
+				} else {
+					// Log feedback of transitive project
+					feedback(x.Version(), pr, fb.DepTypeTransitive, ctx)
+				}
 			}
 		}
-		if newProject {
-			// Check if it's in notondisk project map. These are direct deps, should
-			// be added to manifest.
-			if _, ok := pd.notondisk[pr]; ok {
+	} else {
+		// Get direct dependencies
+		rm, _ := pkgT.ToReachMap(true, true, false, nil)
+		directDep := rm.Flatten(false)
+
+		// Pick the direct dependencies from the above solution and add to manifest
+		for _, x := range l.Projects() {
+			pr := x.Ident().ProjectRoot
+			if contains(directDep, string(pr)) {
 				m.Dependencies[pr] = getProjectPropertiesFromVersion(x.Version())
 				feedback(x.Version(), pr, fb.DepTypeDirect, ctx)
 			} else {
-				// Log feedback of transitive project
 				feedback(x.Version(), pr, fb.DepTypeTransitive, ctx)
 			}
 		}

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

@@ -1,6 +1,6 @@
 {
   "commands": [
-    ["init", "-no-examples"]
+    ["init", "-no-examples", "-gopath"]
   ],
   "gopath-initial": {
     "github.com/sdboyer/deptest": "v0.8.0",

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

@@ -1,6 +1,6 @@
 {
   "commands": [
-    ["init", "-no-examples"]
+    ["init", "-no-examples", "-gopath"]
   ],
   "gopath-initial": {
     "github.com/sdboyer/deptest": "v0.8.0"

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

@@ -1,6 +1,6 @@
 {
   "commands": [
-    ["init", "-no-examples"]
+    ["init", "-no-examples", "-gopath"]
   ],
   "gopath-initial": {
     "github.com/sdboyer/deptestdos": "a0196baa11ea047dd65037287451d36b861b00ea"

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

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

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

@@ -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/main.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/testcase.json

@@ -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"
+  ]
+}