travis: only run the git-validation on pull-requests

Fixes #24

https://docs.travis-ci.com/user/pull-requests/

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

.travis.yml

@@ -11,6 +11,7 @@ before_install:
   - mkdir -p $GOPATH/src/github.com/vbatts && ln -sf $(pwd) $GOPATH/src/github.com/vbatts/git-validation && go get ./...
 
 before_script:
+  - env
   - echo $TRAVIS_COMMIT_RANGE
   - echo $TRAVIS_COMMIT
   - echo $TRAVIS_BRANCH

main.go

@@ -22,6 +22,7 @@ var (
 	flQuiet        = flag.Bool("q", false, "less output")
 	flDir          = flag.String("d", ".", "git directory to validate from")
 	flNoTravis     = flag.Bool("no-travis", false, "disables travis environment checks (when env TRAVIS=true is set)")
+	flTravisPROnly = flag.Bool("travis-pr-only", true, "when on travis, only run validations if the CI-Build is checking pull-request build")
 )
 
 func main() {
@@ -41,6 +42,11 @@ func main() {
 		return
 	}
 
+	if *flTravisPROnly && strings.ToLower(os.Getenv("TRAVIS_PULL_REQUEST")) == "false" {
+		fmt.Printf("only to check travis PR builds and this not a PR build. yielding.\n")
+		return
+	}
+
 	// reduce the set being run
 	rules := validate.RegisteredRules
 	if *flRun != "" {