Move the CLI to urfave/cli v3 (closes #110)

Ported per the library's v2-to-v3 migration guide: the app is a root
cli.Command, actions take a context and the command, and flag
environment variables become value sources. -v, -q and the version flag
are local so, as before, only the commands defining them accept them.
Every command stops reading flags at its first argument, as v2 did.
ErrWriter is stdout so usage errors print with their help. The action's
context reaches the manifest download in check, export and list.
testify rises to v1.12.1, which v3 requires; the urfave_cli_no_docs
build tag, which v3 lacks, is dropped. v3 accepts a flag given under two
names, so -v --verbose gives debug output, and the test pinning the
refusal becomes a TestVerboseCount case.

Model: opus-5-5

internal/cli/errmsg_test.go

@@ -4,7 +4,6 @@ package cli
 import (
 	"bytes"
 	"context"
-	"flag"
 	"net/http"
 	"net/http/httptest"
 	"os"
@@ -15,7 +14,7 @@ import (
 	"github.com/spf13/afero"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
-	urfcli "github.com/urfave/cli/v2"
+	urfcli "github.com/urfave/cli/v3"
 	"sneak.berlin/go/mfer/mfer"
 )
 
@@ -195,13 +194,17 @@ func signedChecker(t *testing.T, manifest []byte) *mfer.Checker {
 func TestPathDoesNotExistMessage(t *testing.T) {
 	t.Parallel()
 
-	set := flag.NewFlagSet("gen", flag.ContinueOnError)
-	require.NoError(t, set.Parse([]string{"nope"}))
-
 	mfa := &CLIApp{Fs: afero.NewMemMapFs()}
-	ctx := urfcli.NewContext(nil, set, nil)
+	cmd := &urfcli.Command{
+		Name: cmdGenerate,
+		Action: func(_ context.Context, c *urfcli.Command) error {
+			_, err := mfa.collectInputPaths(c.Args())
 
-	_, err := mfa.collectInputPaths(ctx.Args())
+			return err
+		},
+	}
+
+	err := cmd.Run(context.Background(), []string{cmdGenerate, "nope"})
 	require.ErrorIs(t, err, errPathNotExist)
 	assert.EqualError(t, err, "path does not exist: nope")
 }
@@ -214,18 +217,22 @@ func TestOutputFileExistsMessage(t *testing.T) {
 	require.NoError(t, afero.WriteFile(fs, "/d/f.txt", []byte("hi"), 0o644))
 	require.NoError(t, afero.WriteFile(fs, "/out.mf", []byte("old"), 0o644))
 
-	set := flag.NewFlagSet("gen", flag.ContinueOnError)
-	set.String("output", "", "")
-	set.Bool("force", false, "")
-	require.NoError(t, set.Parse([]string{"/d"}))
-	require.NoError(t, set.Set("output", "/out.mf"))
-
 	mfa := &CLIApp{Fs: fs}
-	ctx := urfcli.NewContext(nil, set, nil)
+	cmd := &urfcli.Command{
+		Name: cmdGenerate,
+		Flags: []urfcli.Flag{
+			&urfcli.StringFlag{Name: "output"},
+			&urfcli.BoolFlag{Name: "force"},
+		},
+		Action: mfa.generateManifestOperation,
+	}
 
 	// generateManifestOperation writes to the process-global logger during
 	// enumeration, so serialize with the other CLI runs.
-	err := runLocked(func() error { return mfa.generateManifestOperation(ctx) })
+	err := runLocked(func() error {
+		return cmd.Run(context.Background(),
+			[]string{cmdGenerate, "--output", "/out.mf", "/d"})
+	})
 	require.ErrorIs(t, err, errOutputExists)
 	assert.EqualError(t, err,
 		"output file /out.mf already exists (use --force to overwrite)")
@@ -250,7 +257,7 @@ func TestUnknownCommandMessage(t *testing.T) {
 	err := runLocked(func() error {
 		mfa.run([]string{testApp})
 
-		return mfa.app.Run([]string{testApp, "bogus"})
+		return mfa.app.Run(context.Background(), []string{testApp, "bogus"})
 	})
 	require.ErrorIs(t, err, errUnknownCommand)
 	assert.EqualError(t, err, `unknown command "bogus"`)
@@ -267,7 +274,7 @@ func TestManifestLoaderHTTPStatusMessage(t *testing.T) {
 
 	mfa := &CLIApp{Fs: afero.NewMemMapFs()}
 
-	_, err := mfa.openManifestReader(server.URL + "/foo.mf")
+	_, err := mfa.openManifestReader(context.Background(), server.URL+"/foo.mf")
 	require.ErrorIs(t, err, errHTTPStatus)
 	assert.EqualError(t, err,
 		"failed to fetch "+server.URL+"/foo.mf: HTTP 404")
@@ -284,17 +291,13 @@ func TestFetchManifestHTTPStatusMessage(t *testing.T) {
 
 	mfa := &CLIApp{Fs: afero.NewMemMapFs()}
 
-	set := flag.NewFlagSet(cmdFetch, flag.ContinueOnError)
-	for _, f := range mfa.fetchCommand().Flags {
-		require.NoError(t, f.Apply(set))
-	}
-
-	require.NoError(t, set.Parse([]string{server.URL}))
-
-	ctx := urfcli.NewContext(nil, set, nil)
+	cmd := mfa.fetchCommand()
+	cmd.Action = mfa.fetchManifestOperation
 
 	// fetchManifestOperation logs to the process-global logger.
-	err := runLocked(func() error { return mfa.fetchManifestOperation(ctx) })
+	err := runLocked(func() error {
+		return cmd.Run(context.Background(), []string{cmdFetch, server.URL})
+	})
 	require.ErrorIs(t, err, errHTTPStatus)
 	assert.EqualError(t, err, "failed to fetch manifest: HTTP 404")
 }
@@ -320,14 +323,13 @@ func TestFetchFileHTTPStatusMessage(t *testing.T) {
 func TestURLRequiredMessage(t *testing.T) {
 	t.Parallel()
 
-	set := flag.NewFlagSet("fetch", flag.ContinueOnError)
-	require.NoError(t, set.Parse([]string{}))
-
 	mfa := &CLIApp{Fs: afero.NewMemMapFs()}
-	ctx := urfcli.NewContext(nil, set, nil)
+	cmd := &urfcli.Command{Name: cmdFetch, Action: mfa.fetchManifestOperation}
 
 	// fetchManifestOperation logs to the process-global logger.
-	err := runLocked(func() error { return mfa.fetchManifestOperation(ctx) })
+	err := runLocked(func() error {
+		return cmd.Run(context.Background(), []string{cmdFetch})
+	})
 	require.ErrorIs(t, err, errURLRequired)
 	assert.EqualError(t, err, "URL argument required")
 }