Count -v once and document -v -v for debug output (closes #125)

urfave/cli before v2.25.5 counted a flag given by its alias twice, so
one -v or --verbose already gave debug output. Bump it to v2.27.7,
which counts it once: one -v gives verbose output, two give debug.

The -v help text now says -v -v instead of -vv, which stays refused:
urfave/cli's option for combined short flags would let a flag that
takes a value read the next letter as its value.

-v and --verbose together stay refused: urfave/cli v2 refuses a flag
given under two of its names, and one flag with an alias keeps help and
parsing simple.

The bump changes some help output; generate and fetch now name their
arguments. Tests start each run at the default log level.

Model: opus-5-5

Dockerfile

@@ -75,5 +75,7 @@ RUN version="${VERSION:-$(git describe --tags --always)}"; \
 RUN ldd /mfer 2>&1 | grep -q 'not a dynamic executable'
 
 FROM scratch
+# scratch has no CA certificates; fetch needs them to verify HTTPS servers.
+COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
 COPY --from=builder /mfer /mfer
 ENTRYPOINT ["/mfer"]

internal/cli/entry_test.go

@@ -291,9 +291,9 @@ func TestVerboseCount(t *testing.T) {
 	}
 }
 
-// TestCombinedShortVerbose asserts that -vv gives debug output wherever -v
+// TestCombinedShortVerboseRefused asserts that -vv is refused (issue #125):
-// is taken, as the -v help text says (issue #125).
+// single-letter flags do not combine, so the -v help text says -v -v.
-func TestCombinedShortVerbose(t *testing.T) {
+func TestCombinedShortVerboseRefused(t *testing.T) {
 	t.Parallel()
 
 	for _, command := range commandsTakingVerbose() {
@@ -303,15 +303,18 @@ func TestCombinedShortVerbose(t *testing.T) {
 			t.Parallel()
 
 			opts := testOpts(args, afero.NewMemMapFs())
-			_, level := runCLIWithLevel(opts)
+			exitCode, level := runCLIWithLevel(opts)
-			assert.Equal(t, log.DebugLevel, level, "stderr: %s", testStderr(t, opts))
+
+			assert.Equal(t, 1, exitCode)
+			assert.Contains(t, testStderr(t, opts), "flag provided but not defined: -vv")
+			assert.Equal(t, log.InfoLevel, level)
 		})
 	}
 }
 
 // TestShortAndLongVerboseRefused asserts that -v and --verbose given together
-// are refused (issue #125): urfave/cli v2 refuses any flag given under two of
+// are refused (issue #125): urfave/cli v2 refuses a flag given under two of its
-// its names, and accepting it would take parsing the arguments by hand.
+// names, and one flag with an alias keeps help and parsing simple.
 func TestShortAndLongVerboseRefused(t *testing.T) {
 	t.Parallel()
 

internal/cli/mfer.go

@@ -119,7 +119,7 @@ func commonFlags() []cli.Flag {
 		&cli.BoolFlag{
 			Name:    "verbose",
 			Aliases: []string{"v"},
-			Usage:   "Increase verbosity (-v for verbose, -vv for debug)",
+			Usage:   "Increase verbosity (-v for verbose, -v -v for debug)",
 			Count:   new(int),
 		},
 		&cli.BoolFlag{
@@ -328,7 +328,7 @@ func (mfa *CLIApp) fetchCommand() *cli.Command {
 	return &cli.Command{
 		Name:      cmdFetch,
 		Usage:     "fetch manifest and referenced files",
-		ArgsUsage: "[URL]",
+		ArgsUsage: "URL",
 		Action: func(c *cli.Context) error {
 			mfa.setVerbosity(c)
 			mfa.printBanner()
@@ -371,9 +371,6 @@ func (mfa *CLIApp) run(args []string) {
 		Usage:                "Manifest generator",
 		Version:              mfa.VersionString(),
 		EnableBashCompletion: true,
-		// Lets single-letter flags combine, at the root and in every
-		// subcommand: -vv is -v -v.
-		UseShortOptionHandling: true,
 		Writer:               mfa.Stdout,
 		ErrWriter:            mfa.Stderr,
 		Flags:                commonFlags(),