Making prefix matching opt in.

cobra.go

@@ -27,6 +27,10 @@ import (
 
 var initializers []func()
 
+// automatic prefix matching can be a dangerous thing to automatically enable in CLI tools.
+// Set this to true to enable it
+var EnablePrefixMatching bool = false
+
 func OnInitialize(y ...func()) {
 	for _, x := range y {
 		initializers = append(initializers, x)

cobra_test.go

@@ -209,6 +209,7 @@ func TestCommandAlias(t *testing.T) {
 }
 
 func TestPrefixMatching(t *testing.T) {
+	EnablePrefixMatching = true
 	noRRSetupTest("ech times one two")
 
 	if te != nil || tp != nil {
@@ -220,9 +221,22 @@ func TestPrefixMatching(t *testing.T) {
 	if strings.Join(tt, " ") != "one two" {
 		t.Error("Command didn't parse correctly")
 	}
+
+	EnablePrefixMatching = false
+}
+
+func TestNoPrefixMatching(t *testing.T) {
+	EnablePrefixMatching = false
+
+	noRRSetupTest("ech times one two")
+
+	if !(tt == nil && te == nil && tp == nil) {
+		t.Error("Wrong command called")
+	}
 }
 
 func TestAliasPrefixMatching(t *testing.T) {
+	EnablePrefixMatching = true
 	noRRSetupTest("sa times one two")
 
 	if te != nil || tp != nil {
@@ -234,6 +248,7 @@ func TestAliasPrefixMatching(t *testing.T) {
 	if strings.Join(tt, " ") != "one two" {
 		t.Error("Command didn't parse correctly")
 	}
+	EnablePrefixMatching = false
 }
 
 func TestChildSameName(t *testing.T) {

command.go

@@ -290,7 +290,7 @@ func (c *Command) Find(arrs []string) (*Command, []string, error) {
 				for _, cmd := range c.commands {
 					if cmd.Name() == argsWOflags[0] || cmd.HasAlias(argsWOflags[0]) { // exact name or alias match
 						return innerfind(cmd, argsMinusX(args, argsWOflags[0]))
-					} else {
+					} else if EnablePrefixMatching {
 						if strings.HasPrefix(cmd.Name(), argsWOflags[0]) { // prefix match
 							matches = append(matches, cmd)
 						}