From upstream PR: https://github.com/urfave/cli/pull/1299

From: William Wilson <william.wilson@canonical.com>
Date: Tue, 31 Aug 2021 14:19:17 -0500
Subject: Make test case compatible with Go 1.17

As of Go 1.17, the go flag package will panic if given a syntactically invalid
flag. This causes TestApp_RunAsSubCommandIncorrectUsage to panic and therefore
fail. See https://golang.org/doc/go1.17#flag for more information.

---
diff --git a/app_test.go b/app_test.go
index 7c38f6048..76e211d68 100644
--- a/app_test.go
+++ b/app_test.go
@@ -476,18 +476,18 @@ func TestApp_RunAsSubCommandIncorrectUsage(t *testing.T) {
 	a := App{
 		Name: "cmd",
 		Flags: []Flag{
-			&StringFlag{Name: "--foo"},
+			&StringFlag{Name: "foo"},
 		},
 		Writer: bytes.NewBufferString(""),
 	}
 
 	set := flag.NewFlagSet("", flag.ContinueOnError)
-	_ = set.Parse([]string{"", "---foo"})
+	_ = set.Parse([]string{"", "-bar"})
 	c := &Context{flagSet: set}
 
 	err := a.RunAsSubcommand(c)
 
-	expect(t, err, errors.New("bad flag syntax: ---foo"))
+	expect(t, err.Error(), "flag provided but not defined: -bar")
 }
 
 func TestApp_CommandWithFlagBeforeTerminator(t *testing.T) {
ive' href='/guix/log/gnu/packages/libunistring.scm'>log</a><a href='/guix/tree/gnu/packages/libunistring.scm?id=b5ed7b2201b8ca25f90a53e07edd529b4cba2d7c'>tree</a><a href='/guix/commit/gnu/packages/libunistring.scm?id=b5ed7b2201b8ca25f90a53e07edd529b4cba2d7c'>commit</a><a href='/guix/diff/gnu/packages/libunistring.scm?id=b5ed7b2201b8ca25f90a53e07edd529b4cba2d7c'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/gnu/packages/libunistring.scm'>
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<div class='path'>path: <a href='/guix/log/?id=b5ed7b2201b8ca25f90a53e07edd529b4cba2d7c'>root</a>/<a href='/guix/log/gnu?id=b5ed7b2201b8ca25f90a53e07edd529b4cba2d7c'>gnu</a>/<a href='/guix/log/gnu/packages?id=b5ed7b2201b8ca25f90a53e07edd529b4cba2d7c'>packages</a>/<a href='/guix/log/gnu/packages/libunistring.scm?id=b5ed7b2201b8ca25f90a53e07edd529b4cba2d7c'>libunistring.scm</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/gnu/packages/libunistring.scm?id=b5ed7b2201b8ca25f90a53e07edd529b4cba2d7c&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2023-07-20 10:11:26 +0200'>2023-07-20</span></td><td><a href='/guix/commit/gnu/packages/libunistring.scm?id=d4306847bf8736bf60a2ff435fd2d8ef763f769c'>Revert "gnu: libunistring: Fix make check for the Hurd."</a><span class='msg-avail'>...<span class='msg-tooltip'>This reverts commit 12e6a5923812abf180f03bea9e07dd99244a3fcd, which used
XFAIL_TESTS to have 'make check' pass with failing tests "test-perror2"
"test-strerror_r" that now pass with glibc-2.37 and libc-for-target in
commencement.
</span></span></td><td>Janneke Nieuwenhuizen</td></tr>
<tr><td><span title='2023-05-31 07:51:28 +0200'>2023-05-31</span></td><td><a href='/guix/commit/gnu/packages/libunistring.scm?id=12e6a5923812abf180f03bea9e07dd99244a3fcd'>gnu: libunistring: Fix make check for the Hurd.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/libunistring.scm (libunistring)[arguments]: Set XFAIL_TESTS
with test-perror2, and test-strerror_r when building to the Hurd.
</span></span></td><td>Janneke Nieuwenhuizen</td></tr>
<tr><td><span title='2022-05-28 22:01:09 +0300'>2022-05-28</span></td><td><a href='/guix/commit/gnu/packages/libunistring.scm?id=3acb615a3828207d55f52873b669c6917a16e10d'>gnu: libunistring: Rewrite using gexps.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/libunistring.scm (libunistring)[arguments]: Rewrite using
gexps. Remove trailing #t.
</span></span></td><td>Efraim Flashner</td></tr>
<tr><td><span title='2022-05-28 22:01:09 +0300'>2022-05-28</span></td><td><a href='/guix/commit/gnu/packages/libunistring.scm?id=e7fa95dc46e984cdd3b47d89405b8ba304e73dec'>gnu: libunistring: Update to 1.0.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/libunistring.scm (libunistring): Update to 1.0.
[license]: Update in accordance with upstream.
</span></span></td><td>Efraim Flashner</td></tr>