Add "reference" help topic (cli#2223)

rista404 · vilmibm · vilmibm · web-flow · commit e87b5bcaff22 · 2020-11-18T12:31:36.000-06:00
* Add "reference" help topic

* Only print reference as a help topic

* fix for color fns, slightly generalize

* WIP for switching to markdown

* escape gt/lt

* minor

* higher wrap point

* detect terminal theme

* futz with angle brackets once more

* minor cleanup

* prepend parent commands

* rename help topic fns and add test

* Simplify reference help generation

- the `&lt;...&gt;` characters from command usage line are now preserved by enclosing the entire usage synopsis in a code span
- hard breaks in flag usage lines are preserved by enclosing flag usage in a code block
- TTY detection and Markdown rendering are now delayed until the user explicitly requests `gh help reference`
- `gh help reference` output is now pager-enabled

Co-authored-by: vilmibm &lt;vilmibm@github.com&gt;
Co-authored-by: vilmibm &lt;vilmibm@neongrid.space&gt;
Co-authored-by: Mislav Marohnić &lt;mislav@github.com&gt;
diff --git a/pkg/cmd/root/help_reference.go b/pkg/cmd/root/help_reference.go
@@ -0,0 +1,69 @@
+package root
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"strings"
+
+	"github.com/cli/cli/pkg/iostreams"
+	"github.com/cli/cli/pkg/markdown"
+	"github.com/spf13/cobra"
+)
+
+func referenceHelpFn(io *iostreams.IOStreams) func(*cobra.Command, []string) {
+	return func(cmd *cobra.Command, args []string) {
+		wrapWidth := 0
+		style := "notty"
+		if io.IsStdoutTTY() {
+			wrapWidth = io.TerminalWidth()
+			style = markdown.GetStyle(io.DetectTerminalTheme())
+		}
+
+		md, err := markdown.RenderWrap(cmd.Long, style, wrapWidth)
+		if err != nil {
+			fmt.Fprintln(io.ErrOut, err)
+			return
+		}
+
+		if !io.IsStdoutTTY() {
+			fmt.Fprint(io.Out, dedent(md))
+			return
+		}
+
+		_ = io.StartPager()
+		defer io.StopPager()
+		fmt.Fprint(io.Out, md)
+	}
+}
+
+func referenceLong(cmd *cobra.Command) string {
+	buf := bytes.NewBufferString("# gh reference\n\n")
+	for _, c := range cmd.Commands() {
+		if c.Hidden {
+			continue
+		}
+		cmdRef(buf, c, 2)
+	}
+	return buf.String()
+}
+
+func cmdRef(w io.Writer, cmd *cobra.Command, depth int) {
+	// Name + Description
+	fmt.Fprintf(w, "%s `%s`\n\n", strings.Repeat("#", depth), cmd.UseLine())
+	fmt.Fprintf(w, "%s\n\n", cmd.Short)
+
+	// Flags
+	// TODO: fold in InheritedFlags/PersistentFlags, but omit `--help` due to repetitiveness
+	if flagUsages := cmd.Flags().FlagUsages(); flagUsages != "" {
+		fmt.Fprintf(w, "```\n%s````\n\n", dedent(flagUsages))
+	}
+
+	// Subcommands
+	for _, c := range cmd.Commands() {
+		if c.Hidden {
+			continue
+		}
+		cmdRef(w, c, depth+1)
+	}
+}
diff --git a/pkg/cmd/root/help_topic.go b/pkg/cmd/root/help_topic.go
@@ -47,6 +47,9 @@ var HelpTopics = map[string]map[string]string{
 			error if a newer version was found.
 		`),
 	},
+	"reference": {
+		"short": "A comprehensive reference of all gh commands",
+	},
 }
 
 func NewHelpTopic(topic string) *cobra.Command {
@@ -55,8 +58,6 @@ func NewHelpTopic(topic string) *cobra.Command {
 		Short:  HelpTopics[topic]["short"],
 		Long:   HelpTopics[topic]["long"],
 		Hidden: true,
-		Args:   cobra.NoArgs,
-		Run:    helpTopicHelpFunc,
 		Annotations: map[string]string{
 			"markdown:generate": "true",
 			"markdown:basename": "gh_help_" + topic,
diff --git a/pkg/cmd/root/help_topic_test.go b/pkg/cmd/root/help_topic_test.go
@@ -34,7 +34,7 @@ func TestNewHelpTopic(t *testing.T) {
 			topic:    "environment",
 			args:     []string{"invalid"},
 			flags:    []string{},
-			wantsErr: true,
+			wantsErr: false,
 		},
 		{
 			name:     "more than zero flags",
@@ -48,7 +48,7 @@ func TestNewHelpTopic(t *testing.T) {
 			topic:    "environment",
 			args:     []string{"help"},
 			flags:    []string{},
-			wantsErr: true,
+			wantsErr: false,
 		},
 		{
 			name:     "help flag",
diff --git a/pkg/cmd/root/root.go b/pkg/cmd/root/root.go
@@ -92,9 +92,14 @@ func NewCmdRoot(f *cmdutil.Factory, version, buildDate string) *cobra.Command {
 
 	// Help topics
 	cmd.AddCommand(NewHelpTopic("environment"))
+	referenceCmd := NewHelpTopic("reference")
+	referenceCmd.SetHelpFunc(referenceHelpFn(f.IOStreams))
+	cmd.AddCommand(referenceCmd)
 
 	cmdutil.DisableAuthCheck(cmd)
 
+	// this needs to appear last:
+	referenceCmd.Long = referenceLong(cmd)
 	return cmd
 }
 
diff --git a/pkg/markdown/markdown.go b/pkg/markdown/markdown.go
@@ -24,6 +24,23 @@ func Render(text, style string, baseURL string) (string, error) {
 	return tr.Render(text)
 }
 
+func RenderWrap(text, style string, wrap int) (string, error) {
+	// Glamour rendering preserves carriage return characters in code blocks, but
+	// we need to ensure that no such characters are present in the output.
+	text = strings.ReplaceAll(text, "\r\n", "\n")
+
+	tr, err := glamour.NewTermRenderer(
+		glamour.WithStylePath(style),
+		// glamour.WithBaseURL(""),  // TODO: make configurable
+		glamour.WithWordWrap(wrap),
+	)
+	if err != nil {
+		return "", err
+	}
+
+	return tr.Render(text)
+}
+
 func GetStyle(defaultStyle string) string {
 	style := fromEnv()
 	if style != "" && style != "auto" {
