Support for case-insensitive command names (#1802)

Add a global `EnableCaseInsensitive` variable to allow
case-insensitive command names.

The variable supports commands names and aliases globally.

Resolves #1382

cobra.go

@@ -40,14 +40,23 @@ var templateFuncs = template.FuncMap{
 
 var initializers []func()
 
+const (
+	defaultPrefixMatching  = false
+	defaultCommandSorting  = true
+	defaultCaseInsensitive = false
+)
+
 // EnablePrefixMatching allows to set automatic prefix matching. Automatic prefix matching can be a dangerous thing
 // to automatically enable in CLI tools.
 // Set this to true to enable it.
-var EnablePrefixMatching = false
+var EnablePrefixMatching = defaultPrefixMatching
 
 // EnableCommandSorting controls sorting of the slice of commands, which is turned on by default.
 // To disable sorting, set it to false.
-var EnableCommandSorting = true
+var EnableCommandSorting = defaultCommandSorting
+
+// EnableCaseInsensitive allows case-insensitive commands names. (case sensitive by default)
+var EnableCaseInsensitive = defaultCaseInsensitive
 
 // MousetrapHelpText enables an information splash screen on Windows
 // if the CLI is started from explorer.exe.

command.go

@@ -676,7 +676,7 @@ func (c *Command) findSuggestions(arg string) string {
 func (c *Command) findNext(next string) *Command {
 	matches := make([]*Command, 0)
 	for _, cmd := range c.commands {
-		if cmd.Name() == next || cmd.HasAlias(next) {
+		if commandNameMatches(cmd.Name(), next) || cmd.HasAlias(next) {
 			cmd.commandCalledAs.name = next
 			return cmd
 		}
@@ -1328,7 +1328,7 @@ func (c *Command) Name() string {
 // HasAlias determines if a given string is an alias of the command.
 func (c *Command) HasAlias(s string) bool {
 	for _, a := range c.Aliases {
-		if a == s {
+		if commandNameMatches(a, s) {
 			return true
 		}
 	}
@@ -1695,3 +1695,14 @@ func (c *Command) updateParentsPflags() {
 		c.parentsPflags.AddFlagSet(parent.PersistentFlags())
 	})
 }
+
+// commandNameMatches checks if two command names are equal
+// taking into account case sensitivity according to
+// EnableCaseInsensitive global configuration.
+func commandNameMatches(s string, t string) bool {
+	if EnableCaseInsensitive {
+		return strings.EqualFold(s, t)
+	}
+
+	return s == t
+}

command_test.go

@@ -314,7 +314,7 @@ func TestEnablePrefixMatching(t *testing.T) {
 		t.Errorf("aCmdArgs expected: %q, got: %q", onetwo, got)
 	}
 
-	EnablePrefixMatching = false
+	EnablePrefixMatching = defaultPrefixMatching
 }
 
 func TestAliasPrefixMatching(t *testing.T) {
@@ -349,7 +349,7 @@ func TestAliasPrefixMatching(t *testing.T) {
 		t.Errorf("timesCmdArgs expected: %v, got: %v", onetwo, got)
 	}
 
-	EnablePrefixMatching = false
+	EnablePrefixMatching = defaultPrefixMatching
 }
 
 // TestChildSameName checks the correct behaviour of cobra in cases,
@@ -1263,6 +1263,113 @@ func TestSuggestions(t *testing.T) {
 	}
 }
 
+func TestCaseInsensitive(t *testing.T) {
+	rootCmd := &Command{Use: "root", Run: emptyRun}
+	childCmd := &Command{Use: "child", Run: emptyRun, Aliases: []string{"alternative"}}
+	granchildCmd := &Command{Use: "GRANDCHILD", Run: emptyRun, Aliases: []string{"ALIAS"}}
+
+	childCmd.AddCommand(granchildCmd)
+	rootCmd.AddCommand(childCmd)
+
+	tests := []struct {
+		args                []string
+		failWithoutEnabling bool
+	}{
+		{
+			args:                []string{"child"},
+			failWithoutEnabling: false,
+		},
+		{
+			args:                []string{"CHILD"},
+			failWithoutEnabling: true,
+		},
+		{
+			args:                []string{"chILD"},
+			failWithoutEnabling: true,
+		},
+		{
+			args:                []string{"CHIld"},
+			failWithoutEnabling: true,
+		},
+		{
+			args:                []string{"alternative"},
+			failWithoutEnabling: false,
+		},
+		{
+			args:                []string{"ALTERNATIVE"},
+			failWithoutEnabling: true,
+		},
+		{
+			args:                []string{"ALTernatIVE"},
+			failWithoutEnabling: true,
+		},
+		{
+			args:                []string{"alternatiVE"},
+			failWithoutEnabling: true,
+		},
+		{
+			args:                []string{"child", "GRANDCHILD"},
+			failWithoutEnabling: false,
+		},
+		{
+			args:                []string{"child", "grandchild"},
+			failWithoutEnabling: true,
+		},
+		{
+			args:                []string{"CHIld", "GRANdchild"},
+			failWithoutEnabling: true,
+		},
+		{
+			args:                []string{"alternative", "ALIAS"},
+			failWithoutEnabling: false,
+		},
+		{
+			args:                []string{"alternative", "alias"},
+			failWithoutEnabling: true,
+		},
+		{
+			args:                []string{"CHILD", "alias"},
+			failWithoutEnabling: true,
+		},
+		{
+			args:                []string{"CHIld", "aliAS"},
+			failWithoutEnabling: true,
+		},
+	}
+
+	for _, test := range tests {
+		for _, enableCaseInsensitivity := range []bool{true, false} {
+			EnableCaseInsensitive = enableCaseInsensitivity
+
+			output, err := executeCommand(rootCmd, test.args...)
+			expectedFailure := test.failWithoutEnabling && !enableCaseInsensitivity
+
+			if !expectedFailure && output != "" {
+				t.Errorf("Unexpected output: %v", output)
+			}
+			if !expectedFailure && err != nil {
+				t.Errorf("Unexpected error: %v", err)
+			}
+		}
+	}
+
+	EnableCaseInsensitive = defaultCaseInsensitive
+}
+
+// This test make sure we keep backwards-compatibility with respect
+// to command names case sensitivity behavior.
+func TestCaseSensitivityBackwardCompatibility(t *testing.T) {
+	rootCmd := &Command{Use: "root", Run: emptyRun}
+	childCmd := &Command{Use: "child", Run: emptyRun}
+
+	rootCmd.AddCommand(childCmd)
+	_, err := executeCommand(rootCmd, strings.ToUpper(childCmd.Use))
+	if err == nil {
+		t.Error("Expected error on calling a command in upper case while command names are case sensitive. Got nil.")
+	}
+
+}
+
 func TestRemoveCommand(t *testing.T) {
 	rootCmd := &Command{Use: "root", Args: NoArgs, Run: emptyRun}
 	childCmd := &Command{Use: "child", Run: emptyRun}
@@ -1622,7 +1729,7 @@ func TestCommandsAreSorted(t *testing.T) {
 		}
 	}
 
-	EnableCommandSorting = true
+	EnableCommandSorting = defaultCommandSorting
 }
 
 func TestEnableCommandSortingIsDisabled(t *testing.T) {
@@ -1643,7 +1750,7 @@ func TestEnableCommandSortingIsDisabled(t *testing.T) {
 		}
 	}
 
-	EnableCommandSorting = true
+	EnableCommandSorting = defaultCommandSorting
 }
 
 func TestSetOutput(t *testing.T) {