Add methods to increment version number

version.go

@@ -12,18 +12,25 @@ import (
 // The compiled version of the regex created at init() is cached here so it
 // only needs to be created once.
 var versionRegex *regexp.Regexp
+var validPrereleaseRegex *regexp.Regexp
 
 var (
 	// ErrInvalidSemVer is returned a version is found to be invalid when
 	// being parsed.
-	ErrInvalidSemVer = errors.New("Invalid Semantic Version")
+	ErrInvalidSemVer     = errors.New("Invalid Semantic Version")
+	ErrInvalidMetadata   = errors.New("Invalid Metadata string")
+	ErrInvalidPrerelease = errors.New("Invalid Prerelease string")
 )
 
-// SemVerRegex id the regular expression used to parse a semantic version.
+// SemVerRegex is the regular expression used to parse a semantic version.
 const SemVerRegex string = `v?([0-9]+)(\.[0-9]+)?(\.[0-9]+)?` +
 	`(-([0-9A-Za-z\-]+(\.[0-9A-Za-z\-]+)*))?` +
 	`(\+([0-9A-Za-z\-]+(\.[0-9A-Za-z\-]+)*))?`
 
+// ValidPrerelease is the regular expression which validates
+// both prerelease and metadata values.
+const ValidPrerelease string = `^([0-9A-Za-z\-]+(\.[0-9A-Za-z\-]+)*)`
+
 // Version represents a single semantic version.
 type Version struct {
 	major, minor, patch int64
@@ -34,6 +41,7 @@ type Version struct {
 
 func init() {
 	versionRegex = regexp.MustCompile("^" + SemVerRegex + "$")
+	validPrereleaseRegex = regexp.MustCompile(ValidPrerelease)
 }
 
 // NewVersion parses a given version and returns an instance of Version or
@@ -129,6 +137,93 @@ func (v *Version) Metadata() string {
 	return v.metadata
 }
 
+// originalVPrefix returns the original 'v' prefix if any.
+func (v *Version) originalVPrefix() string {
+	if v.original != "" && strings.ToLower(v.original[:1]) == "v" {
+		return v.original[:1]
+	}
+	return ""
+}
+
+// IncPatch produces the next patch version.
+// If the current version does not have prerelease/metadata information,
+// it unsets metadata and prerelease values, increments patch number.
+// If the current version has any of prerelease or metadata information,
+// it unsets both values and keeps curent patch value
+func (v Version) IncPatch() Version {
+	vNext := v
+	// according to http://semver.org/#spec-item-9
+	// Pre-release versions have a lower precedence than the associated normal version.
+	// according to http://semver.org/#spec-item-10
+	// Build metadata SHOULD be ignored when determining version precedence.
+	if v.pre != "" {
+		vNext.metadata = ""
+		vNext.pre = ""
+	} else {
+		vNext.metadata = ""
+		vNext.pre = ""
+		vNext.patch = v.patch + 1
+	}
+	vNext.original = v.originalVPrefix() + "" + vNext.String()
+	return vNext
+}
+
+// IncMinor produces the next minor version.
+// Sets patch to 0.
+// Increments minor number.
+// Unsets metadata.
+// Unsets prerelease status.
+func (v Version) IncMinor() Version {
+	vNext := v
+	vNext.metadata = ""
+	vNext.pre = ""
+	vNext.patch = 0
+	vNext.minor = v.minor + 1
+	vNext.original = v.originalVPrefix() + "" + vNext.String()
+	return vNext
+}
+
+// IncMajor produces the next major version.
+// Sets patch to 0.
+// Sets minor to 0.
+// Increments major number.
+// Unsets metadata.
+// Unsets prerelease status.
+func (v Version) IncMajor() Version {
+	vNext := v
+	vNext.metadata = ""
+	vNext.pre = ""
+	vNext.patch = 0
+	vNext.minor = 0
+	vNext.major = v.major + 1
+	vNext.original = v.originalVPrefix() + "" + vNext.String()
+	return vNext
+}
+
+// SetPrelease defines the prerelease value.
+// Value must not include the required 'hypen' prefix.
+func (v Version) SetPrerelease(prerelease string) (Version, error) {
+	vNext := v
+	if len(prerelease) > 0 && validPrereleaseRegex.MatchString(prerelease) == false {
+		return vNext, ErrInvalidPrerelease
+	}
+	vNext.pre = prerelease
+	vNext.original = v.originalVPrefix() + "" + vNext.String()
+	return vNext, nil
+}
+
+// SetMetadata defines metadata value.
+// Value must not include the required 'plus' prefix.
+func (v Version) SetMetadata(metadata string) (Version, error) {
+	vNext := v
+	if len(metadata) > 0 && validPrereleaseRegex.MatchString(metadata) == false {
+		return vNext, ErrInvalidMetadata
+	}
+	vNext.metadata = metadata
+	vNext.original = v.originalVPrefix() + "" + vNext.String()
+	return vNext, nil
+}
+
 // LessThan tests if one version is less than another one.
 func (v *Version) LessThan(o *Version) bool {
 	return v.Compare(o) < 0

version_test.go

@@ -281,3 +281,170 @@ func TestEqual(t *testing.T) {
 		}
 	}
 }
+
+func TestInc(t *testing.T) {
+	tests := []struct {
+		v1               string
+		expected         string
+		how              string
+		expectedOriginal string
+	}{
+		{"1.2.3", "1.2.4", "patch", "1.2.4"},
+		{"v1.2.4", "1.2.5", "patch", "v1.2.5"},
+		{"1.2.3", "1.3.0", "minor", "1.3.0"},
+		{"v1.2.4", "1.3.0", "minor", "v1.3.0"},
+		{"1.2.3", "2.0.0", "major", "2.0.0"},
+		{"v1.2.4", "2.0.0", "major", "v2.0.0"},
+		{"1.2.3+meta", "1.2.4", "patch", "1.2.4"},
+		{"1.2.3-beta+meta", "1.2.3", "patch", "1.2.3"},
+		{"v1.2.4-beta+meta", "1.2.4", "patch", "v1.2.4"},
+		{"1.2.3-beta+meta", "1.3.0", "minor", "1.3.0"},
+		{"v1.2.4-beta+meta", "1.3.0", "minor", "v1.3.0"},
+		{"1.2.3-beta+meta", "2.0.0", "major", "2.0.0"},
+		{"v1.2.4-beta+meta", "2.0.0", "major", "v2.0.0"},
+	}
+
+	for _, tc := range tests {
+		v1, err := NewVersion(tc.v1)
+		if err != nil {
+			t.Errorf("Error parsing version: %s", err)
+		}
+
+		var v2 Version
+		switch tc.how {
+		case "patch":
+			v2 = v1.IncPatch()
+		case "minor":
+			v2 = v1.IncMinor()
+		case "major":
+			v2 = v1.IncMajor()
+		}
+
+		a := v2.String()
+		e := tc.expected
+		if a != e {
+			t.Errorf(
+				"Inc %q failed. Expected %q got %q",
+				tc.how, e, a,
+			)
+		}
+
+		a = v2.Original()
+		e = tc.expectedOriginal
+		if a != e {
+			t.Errorf(
+				"Inc %q failed. Expected original %q got %q",
+				tc.how, e, a,
+			)
+		}
+	}
+}
+
+func TestSetPrerelease(t *testing.T) {
+	tests := []struct {
+		v1                 string
+		prerelease         string
+		expectedVersion    string
+		expectedPrerelease string
+		expectedOriginal   string
+		expectedErr        error
+	}{
+		{"1.2.3", "**", "1.2.3", "", "1.2.3", ErrInvalidPrerelease},
+		{"1.2.3", "beta", "1.2.3-beta", "beta", "1.2.3-beta", nil},
+		{"v1.2.4", "beta", "1.2.4-beta", "beta", "v1.2.4-beta", nil},
+	}
+
+	for _, tc := range tests {
+		v1, err := NewVersion(tc.v1)
+		if err != nil {
+			t.Errorf("Error parsing version: %s", err)
+		}
+
+		v2, err := v1.SetPrerelease(tc.prerelease)
+		if err != tc.expectedErr {
+			t.Errorf("Expected to get err=%s, but got err=%s", tc.expectedErr, err)
+		}
+
+		a := v2.Prerelease()
+		e := tc.expectedPrerelease
+		if a != e {
+			t.Errorf("Expected prerelease value=%q, but got %q", e, a)
+		}
+
+		a = v2.String()
+		e = tc.expectedVersion
+		if a != e {
+			t.Errorf("Expected version string=%q, but got %q", e, a)
+		}
+
+		a = v2.Original()
+		e = tc.expectedOriginal
+		if a != e {
+			t.Errorf("Expected version original=%q, but got %q", e, a)
+		}
+	}
+}
+
+func TestSetMetadata(t *testing.T) {
+	tests := []struct {
+		v1               string
+		metadata         string
+		expectedVersion  string
+		expectedMetadata string
+		expectedOriginal string
+		expectedErr      error
+	}{
+		{"1.2.3", "**", "1.2.3", "", "1.2.3", ErrInvalidMetadata},
+		{"1.2.3", "meta", "1.2.3+meta", "meta", "1.2.3+meta", nil},
+		{"v1.2.4", "meta", "1.2.4+meta", "meta", "v1.2.4+meta", nil},
+	}
+
+	for _, tc := range tests {
+		v1, err := NewVersion(tc.v1)
+		if err != nil {
+			t.Errorf("Error parsing version: %s", err)
+		}
+
+		v2, err := v1.SetMetadata(tc.metadata)
+		if err != tc.expectedErr {
+			t.Errorf("Expected to get err=%s, but got err=%s", tc.expectedErr, err)
+		}
+
+		a := v2.Metadata()
+		e := tc.expectedMetadata
+		if a != e {
+			t.Errorf("Expected metadata value=%q, but got %q", e, a)
+		}
+
+		a = v2.String()
+		e = tc.expectedVersion
+		if e != a {
+			t.Errorf("Expected version string=%q, but got %q", e, a)
+		}
+
+		a = v2.Original()
+		e = tc.expectedOriginal
+		if a != e {
+			t.Errorf("Expected version original=%q, but got %q", e, a)
+		}
+	}
+}
+
+func TestOriginalVPrefix(t *testing.T) {
+	tests := []struct {
+		version string
+		vprefix string
+	}{
+		{"1.2.3", ""},
+		{"v1.2.4", "v"},
+	}
+
+	for _, tc := range tests {
+		v1, _ := NewVersion(tc.version)
+		a := v1.originalVPrefix()
+		e := tc.vprefix
+		if a != e {
+			t.Errorf("Expected vprefix=%q, but got %q", e, a)
+		}
+	}
+}