From df56fef0d267b6e790b64a33252180115080cc83 Mon Sep 17 00:00:00 2001
From: Paul Holzinger <paul.holzinger@web.de>
Date: Thu, 15 Oct 2020 13:10:34 +0200
Subject: [PATCH] Custom completion handle multiple shorhand flags together

Flag definitions like `-asd` are not handled correctly by
the custom completion logic. They should be treated as
multiple flags. For details refer to #1257.

Fixes #1257

Signed-off-by: Paul Holzinger <paul.holzinger@web.de>
---
 custom_completions.go      |  7 +++--
 custom_completions_test.go | 62 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+), 2 deletions(-)

diff --git a/custom_completions.go b/custom_completions.go
index f9e88e081..05937631f 100644
--- a/custom_completions.go
+++ b/custom_completions.go
@@ -459,8 +459,11 @@ func checkIfFlagCompletion(finalCmd *Command, args []string, lastArg string) (*p
 				// If the flag contains an = it means it has already been fully processed,
 				// so we don't need to deal with it here.
 				if index := strings.Index(prevArg, "="); index < 0 {
-					flagName = strings.TrimLeft(prevArg, "-")
-
+					if strings.HasPrefix(prevArg, "--") {
+						flagName = prevArg[2:]
+					} else {
+						flagName = prevArg[len(prevArg)-1:]
+					}
 					// Remove the uncompleted flag or else there could be an error created
 					// for an invalid value for that flag
 					trimmedArgs = args[:len(args)-1]
diff --git a/custom_completions_test.go b/custom_completions_test.go
index 14ec5a9eb..450a0e18a 100644
--- a/custom_completions_test.go
+++ b/custom_completions_test.go
@@ -1958,3 +1958,65 @@ func TestCompleteHelp(t *testing.T) {
 		t.Errorf("expected: %q, got: %q", expected, output)
 	}
 }
+
+func TestMultipleShorthandFlagCompletion(t *testing.T) {
+	rootCmd := &Command{
+		Use:       "root",
+		ValidArgs: []string{"foo", "bar"},
+		Run:       emptyRun,
+	}
+	f := rootCmd.Flags()
+	f.BoolP("short", "s", false, "short flag 1")
+	f.BoolP("short2", "d", false, "short flag 2")
+	f.StringP("short3", "f", "", "short flag 3")
+	rootCmd.RegisterFlagCompletionFunc("short3", func(*Command, []string, string) ([]string, ShellCompDirective) {
+		return []string{"works"}, ShellCompDirectiveNoFileComp
+	})
+
+	// Test that a single shorthand flag works
+	output, err := executeCommand(rootCmd, ShellCompNoDescRequestCmd, "-s", "")
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	expected := strings.Join([]string{
+		"foo",
+		"bar",
+		":4",
+		"Completion ended with directive: ShellCompDirectiveNoFileComp", ""}, "\n")
+
+	if output != expected {
+		t.Errorf("expected: %q, got: %q", expected, output)
+	}
+
+	// Test that multiple boolean shorthand flags work
+	output, err = executeCommand(rootCmd, ShellCompNoDescRequestCmd, "-sd", "")
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	expected = strings.Join([]string{
+		"foo",
+		"bar",
+		":4",
+		"Completion ended with directive: ShellCompDirectiveNoFileComp", ""}, "\n")
+
+	if output != expected {
+		t.Errorf("expected: %q, got: %q", expected, output)
+	}
+
+	// Test that multiple boolean + string shorthand flags work
+	output, err = executeCommand(rootCmd, ShellCompNoDescRequestCmd, "-sdf", "")
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	expected = strings.Join([]string{
+		"works",
+		":4",
+		"Completion ended with directive: ShellCompDirectiveNoFileComp", ""}, "\n")
+
+	if output != expected {
+		t.Errorf("expected: %q, got: %q", expected, output)
+	}
+}