From 3bf635dc60b93a8178a3c0ca2d6cec36e5f15d37 Mon Sep 17 00:00:00 2001
From: Katy Moe <katy@katy.moe>
Date: Thu, 21 Apr 2022 11:56:41 +0100
Subject: [PATCH 1/2] add failing test for subcommand argument parsing

Add a failing test demonstrating that "fooasdf -o=foo" is incorrectly
matched to the subcommand "foo".
---
 cli_test.go | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/cli_test.go b/cli_test.go
index 3083937..e381d54 100644
--- a/cli_test.go
+++ b/cli_test.go
@@ -171,6 +171,40 @@ func TestCLIRun_prefix(t *testing.T) {
 	}
 }
 
+// NOTE: This failing test is intended to demonstrate incorrect behaviour
+// in which a subcommand with an arbitrary suffix is still parsed as that
+// subcommand, if a supplied argument is also suffixed by that subcommand.
+func TestCLIRun_subcommandSuffix(t *testing.T) {
+	buf := new(bytes.Buffer)
+	command := new(MockCommand)
+	cli := &CLI{
+		Args: []string{"fooasdf", "-o=foo"},
+		Commands: map[string]CommandFactory{
+			"foo": func() (Command, error) {
+				return command, nil
+			},
+
+			"foo bar": func() (Command, error) {
+				return command, nil
+			},
+		},
+		ErrorWriter: buf,
+	}
+
+	exitCode, err := cli.Run()
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	if exitCode != 127 {
+		t.Fatalf("expected to get exit code 127, but got %d", exitCode)
+	}
+
+	if command.RunCalled {
+		t.Fatalf("run should not be called")
+	}
+}
+
 func TestCLIRun_default(t *testing.T) {
 	commandBar := new(MockCommand)
 	commandBar.RunResult = 42

From 4bb9ba29a559edb1ee92e200cf9669a7f275e2de Mon Sep 17 00:00:00 2001
From: Katy Moe <katy@katy.moe>
Date: Thu, 21 Apr 2022 11:58:12 +0100
Subject: [PATCH 2/2] exclude flags from subcommand parsing

When determining the string to use when querying the radix tree for the
longest subcommand, exclude any argument beginning with a "-", since
this is a flag and not a subcommand.

This fixes a bug in which "fooasdf -o=foo" is matched to the subcommand
"foo" due to logic further down on line 704.
---
 cli.go      | 8 ++++----
 cli_test.go | 3 ---
 2 files changed, 4 insertions(+), 7 deletions(-)

diff --git a/cli.go b/cli.go
index 31fafa0..a2abfe1 100644
--- a/cli.go
+++ b/cli.go
@@ -680,12 +680,12 @@ func (c *CLI) processArgs() {
 				}
 
 				// Determine the argument we look to to end subcommands.
-				// We look at all arguments until one has a space. This
-				// disallows commands like: ./cli foo "bar baz". An argument
-				// with a space is always an argument.
+				// We look at all arguments until one is a flag or has a space.
+				// This disallows commands like: ./cli foo "bar baz". An
+				// argument with a space is always an argument.
 				j := 0
 				for k, v := range c.Args[i:] {
-					if strings.ContainsRune(v, ' ') {
+					if strings.ContainsRune(v, ' ') || v[0] == '-' {
 						break
 					}
 
diff --git a/cli_test.go b/cli_test.go
index e381d54..6b6014e 100644
--- a/cli_test.go
+++ b/cli_test.go
@@ -171,9 +171,6 @@ func TestCLIRun_prefix(t *testing.T) {
 	}
 }
 
-// NOTE: This failing test is intended to demonstrate incorrect behaviour
-// in which a subcommand with an arbitrary suffix is still parsed as that
-// subcommand, if a supplied argument is also suffixed by that subcommand.
 func TestCLIRun_subcommandSuffix(t *testing.T) {
 	buf := new(bytes.Buffer)
 	command := new(MockCommand)