Show latest version

CHANGELOG.md

@@ -6,6 +6,8 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Added
+- `latest` command to show latest release version number ([#5](https://github.com/cucumber/changelog/pull/5))
 
 ## [0.9.2] - 2021-11-11
 ### Added
@@ -14,6 +16,9 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ### Fixed
 - config for releasing to Cucumber's docker account
 
+## [0.9.1] - 2021-11-11
+Failed release
+
 ## [0.9.0] - 2021-11-11
 ### Fixed
 - Show command was broken ([#4](https://github.com/cucumber/changelog/issues/4))

README.md

@@ -36,6 +36,9 @@ $ changelog init --compare-url=https://github.com/myorg/myrepo/compare/abcdef...
 $ changelog added "Initial commit"
 # Create release
 $ changelog release 0.1.0
+# Show latest release number
+$ changelog latest
+=> 0.1.0
 ```
 
 ## Installation
@@ -78,6 +81,7 @@ Available Commands:
   fmt         Reformat the change log file
   help        Help about any command
   init        Initializes a new changelog
+  latest      Show latest released version number
   release     Change Unreleased to [version]
   removed     Add item under 'Removed' section
   security    Add item under 'Security' section

chg/changelog.go

@@ -150,3 +150,13 @@ func (c *Changelog) Render(w io.Writer) {
 		w.Write(content)
 	}
 }
+
+func (c *Changelog) ReleasedVersions() []Version {
+	var result []Version
+	for _, version := range c.Versions {
+		if version.Name != "Unreleased" {
+			result = append(result, *version)
+		}
+	}
+	return result
+}

cmd/latest.go

@@ -0,0 +1,33 @@
+package cmd
+
+import (
+	"fmt"
+	"io"
+
+	"github.com/cucumber/changelog/parser"
+	"github.com/spf13/cobra"
+)
+
+func newLatestCmd(iostreams *IOStreams) *cobra.Command {
+	return &cobra.Command{
+		Use:   "latest",
+		Short: "Show latest released version number",
+		Long:  `Show version number for the top (released) entry in the changelog`,
+		Args:  cobra.ExactArgs(0),
+		RunE: func(cmd *cobra.Command, args []string) error {
+			changelog := parser.Parse(iostreams.In)
+			if len(changelog.Versions) == 0 {
+				cmd.SilenceUsage = true
+				return fmt.Errorf("There are no versions in the changelog yet")
+			}
+			releasedVersions := changelog.ReleasedVersions()
+			if len(releasedVersions) == 0 {
+				cmd.SilenceUsage = true
+				return fmt.Errorf("There are no released versions in the changelog yet")
+			}
+			v := releasedVersions[0]
+			io.WriteString(iostreams.Out, v.Name+"\n")
+			return nil
+		},
+	}
+}

cmd/latest_test.go

@@ -0,0 +1,92 @@
+package cmd
+
+import (
+	"bytes"
+	"io/ioutil"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestLatestCmdShowsLatestReleasedVersion(t *testing.T) {
+	changelog, err := ioutil.ReadFile("testdata/show-changelog.md")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	expected := `1.0.0
+`
+
+	out := new(bytes.Buffer)
+	iostreams := &IOStreams{
+		In:  bytes.NewBuffer(changelog),
+		Out: out,
+	}
+
+	cmd := newLatestCmd(iostreams)
+	_, err = cmd.ExecuteC()
+
+	assert.Nil(t, err)
+	assert.Equal(t, expected, string(out.Bytes()))
+}
+func TestLatestCmdShowsLatestReleasedVersionEvenWhenNoUnreleased(t *testing.T) {
+	changelog, err := ioutil.ReadFile("testdata/legacy-changelog.md")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	expected := `1.0.0
+`
+
+	out := new(bytes.Buffer)
+	iostreams := &IOStreams{
+		In:  bytes.NewBuffer(changelog),
+		Out: out,
+	}
+
+	cmd := newLatestCmd(iostreams)
+	_, err = cmd.ExecuteC()
+
+	assert.Nil(t, err)
+	assert.Equal(t, expected, string(out.Bytes()))
+}
+
+func TestLatestCmdError(t *testing.T) {
+	changelog, err := ioutil.ReadFile("testdata/empty-changelog.md")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	out := new(bytes.Buffer)
+	iostreams := &IOStreams{
+		In:  bytes.NewBuffer(changelog),
+		Out: out,
+	}
+
+	cmd := newLatestCmd(iostreams)
+	_, err = cmd.ExecuteC()
+
+	assert.Error(t, err)
+	expected := "There are no versions in the changelog yet"
+	assert.EqualError(t, err, expected)
+}
+
+func TestLatestCmdErrorWhenNoReleasedVersions(t *testing.T) {
+	changelog, err := ioutil.ReadFile("testdata/minimal-changelog.md")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	out := new(bytes.Buffer)
+	iostreams := &IOStreams{
+		In:  bytes.NewBuffer(changelog),
+		Out: out,
+	}
+
+	cmd := newLatestCmd(iostreams)
+	_, err = cmd.ExecuteC()
+
+	assert.Error(t, err)
+	expected := "There are no released versions in the changelog yet"
+	assert.EqualError(t, err, expected)
+}

cmd/root.go

@@ -65,6 +65,7 @@ func init() {
 		newFmtCmd(ioStreams),
 		newReleaseCmd(ioStreams),
 		newShowCmd(ioStreams),
+		newLatestCmd(ioStreams),
 	)
 
 	manipulationCmds := newChangeTypeCmds(ioStreams)

cmd/testdata/legacy-changelog.md

@@ -0,0 +1,18 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
+and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
+
+This is an example of a legacy changelog we might have inherited that hasn't been properly formatted and doesn't have an Unreleased section.
+
+## [1.0.0] - 2020-01-08
+### Added
+- Item 1
+- Item 2
+
+### Changed
+- Item 3
+
+[1.0.0]: https://github.com/rcmachado/changelog/compare/ae761ff...1.0.0