message_regexp: regular expression rule for messages

Fixes: #30

now you can add a regular expression to the rules to be run
i.e. `git-validation -run "dco,message_regexp='^JIRA-[0-9]+ [A-Z].*$'"`

Signed-off-by: Vincent Batts <vbatts@hashbangbash.com>

rules/danglingwhitespace/rule.go

@@ -12,6 +12,7 @@ var (
 		Name:        "dangling-whitespace",
 		Description: "checking the presence of dangling whitespaces on line endings",
 		Run:         ValidateDanglingWhitespace,
+		Default:     true,
 	}
 )
 
@@ -20,7 +21,7 @@ func init() {
 }
 
 // ValidateDanglingWhitespace runs Git's check to look for whitespace errors.
-func ValidateDanglingWhitespace(c git.CommitEntry) (vr validate.Result) {
+func ValidateDanglingWhitespace(r validate.Rule, c git.CommitEntry) (vr validate.Result) {
 	vr.CommitEntry = c
 	vr.Msg = "commit does not have any whitespace errors"
 	vr.Pass = true

rules/dco/dco.go

@@ -20,11 +20,12 @@ var (
 		Name:        "DCO",
 		Description: "makes sure the commits are signed",
 		Run:         ValidateDCO,
+		Default:     true,
 	}
 )
 
 // ValidateDCO checks that the commit has been signed off, per the DCO process
-func ValidateDCO(c git.CommitEntry) (vr validate.Result) {
+func ValidateDCO(r validate.Rule, c git.CommitEntry) (vr validate.Result) {
 	vr.CommitEntry = c
 	if len(strings.Split(c["parent"], " ")) > 1 {
 		vr.Pass = true

rules/messageregexp/rule.go

@@ -0,0 +1,61 @@
+package messageregexp
+
+import (
+	"fmt"
+	"regexp"
+	"strings"
+
+	"github.com/vbatts/git-validation/git"
+	"github.com/vbatts/git-validation/validate"
+)
+
+func init() {
+	validate.RegisterRule(RegexpRule)
+}
+
+var (
+	// RegexpRule for validating a user provided regex on the commit messages
+	RegexpRule = validate.Rule{
+		Name:        "message_regexp",
+		Description: "checks the commit message for a user provided regular expression",
+		Run:         ValidateMessageRegexp,
+		Default:     false, // only for users specifically calling it through -run ...
+	}
+)
+
+// ValidateMessageRegexp is the message regex func to run
+func ValidateMessageRegexp(r validate.Rule, c git.CommitEntry) (vr validate.Result) {
+	if r.Value == "" {
+		vr.Pass = true
+		vr.Msg = "noop: message_regexp value is blank"
+		return vr
+	}
+
+	re := regexp.MustCompile(r.Value)
+	vr.CommitEntry = c
+	if len(strings.Split(c["parent"], " ")) > 1 {
+		vr.Pass = true
+		vr.Msg = "merge commits are not checked for message_regexp"
+		return vr
+	}
+
+	hasValid := false
+	for _, line := range strings.Split(c["subject"], "\n") {
+		if re.MatchString(line) {
+			hasValid = true
+		}
+	}
+	for _, line := range strings.Split(c["body"], "\n") {
+		if re.MatchString(line) {
+			hasValid = true
+		}
+	}
+	if !hasValid {
+		vr.Pass = false
+		vr.Msg = fmt.Sprintf("commit message does not match %q", r.Value)
+	} else {
+		vr.Pass = true
+		vr.Msg = fmt.Sprintf("commit message matches %q", r.Value)
+	}
+	return vr
+}

rules/shortsubject/shortsubject.go

@@ -11,6 +11,7 @@ var (
 		Name:        "short-subject",
 		Description: "commit subjects are strictly less than 90 (github ellipsis length)",
 		Run:         ValidateShortSubject,
+		Default:     true,
 	}
 )
 
@@ -20,7 +21,7 @@ func init() {
 
 // ValidateShortSubject checks that the commit's subject is strictly less than
 // 90 characters (preferably not more than 72 chars).
-func ValidateShortSubject(c git.CommitEntry) (vr validate.Result) {
+func ValidateShortSubject(r validate.Rule, c git.CommitEntry) (vr validate.Result) {
 	if len(c["subject"]) >= 90 {
 		vr.Pass = false
 		vr.Msg = "commit subject exceeds 90 characters"