fix: align github.ref to GitHub Action (#1362)

* fix: align github.ref to GitHub Action

The `github.ref` value should be `refs/heads/branch` in most cases.
There are a few exceptions handled by the code.

This change prefixes the default case with `refs/heads` and adds
tests for this and the excpetional cases.

* fix: correct existing assertions

pkg/model/github_context.go

@@ -95,7 +95,7 @@ func (ghc *GithubContext) SetRefAndSha(ctx context.Context, defaultBranch string
 	// https://docs.github.com/en/developers/webhooks-and-events/webhooks/webhook-events-and-payloads
 	switch ghc.EventName {
 	case "pull_request_target":
-		ghc.Ref = ghc.BaseRef
+		ghc.Ref = fmt.Sprintf("refs/heads/%s", ghc.BaseRef)
 		ghc.Sha = asString(nestedMapLookup(ghc.Event, "pull_request", "base", "sha"))
 	case "pull_request", "pull_request_review", "pull_request_review_comment":
 		ghc.Ref = fmt.Sprintf("refs/pull/%.0f/merge", ghc.Event["number"])
@@ -110,7 +110,10 @@ func (ghc *GithubContext) SetRefAndSha(ctx context.Context, defaultBranch string
 			ghc.Sha = asString(ghc.Event["after"])
 		}
 	default:
-		ghc.Ref = asString(nestedMapLookup(ghc.Event, "repository", "default_branch"))
+		defaultBranch := asString(nestedMapLookup(ghc.Event, "repository", "default_branch"))
+		if defaultBranch != "" {
+			ghc.Ref = fmt.Sprintf("refs/heads/%s", defaultBranch)
+		}
 	}
 
 	if ghc.Ref == "" {
@@ -130,7 +133,7 @@ func (ghc *GithubContext) SetRefAndSha(ctx context.Context, defaultBranch string
 		}
 
 		if ghc.Ref == "" {
-			ghc.Ref = asString(nestedMapLookup(ghc.Event, "repository", "default_branch"))
+			ghc.Ref = fmt.Sprintf("refs/heads/%s", asString(nestedMapLookup(ghc.Event, "repository", "default_branch")))
 		}
 	}
 

pkg/model/github_context_test.go

@@ -40,7 +40,7 @@ func TestSetRefAndSha(t *testing.T) {
 					},
 				},
 			},
-			ref: "master",
+			ref: "refs/heads/master",
 			sha: "pr-base-sha",
 		},
 		{
@@ -89,7 +89,7 @@ func TestSetRefAndSha(t *testing.T) {
 					"default_branch": "main",
 				},
 			},
-			ref: "main",
+			ref: "refs/heads/main",
 			sha: "1234fakesha",
 		},
 		{
@@ -127,7 +127,7 @@ func TestSetRefAndSha(t *testing.T) {
 
 		ghc.SetRefAndSha(context.Background(), "", "/some/dir")
 
-		assert.Equal(t, "master", ghc.Ref)
+		assert.Equal(t, "refs/heads/master", ghc.Ref)
 		assert.Equal(t, "1234fakesha", ghc.Sha)
 	})
 }

pkg/runner/run_context.go

@@ -486,7 +486,7 @@ func (rc *RunContext) getGithubContext(ctx context.Context) *model.GithubContext
 		}
 	}
 
-	if ghc.EventName == "pull_request" {
+	if ghc.EventName == "pull_request" || ghc.EventName == "pull_request_target" {
 		ghc.BaseRef = asString(nestedMapLookup(ghc.Event, "pull_request", "base", "ref"))
 		ghc.HeadRef = asString(nestedMapLookup(ghc.Event, "pull_request", "head", "ref"))
 	}

pkg/runner/run_context_test.go

@@ -396,6 +396,48 @@ func TestGetGitHubContext(t *testing.T) {
 	assert.Equal(t, ghc.Token, rc.Config.Secrets["GITHUB_TOKEN"])
 }
 
+func TestGetGithubContextRef(t *testing.T) {
+	table := []struct {
+		event string
+		json  string
+		ref   string
+	}{
+		{event: "push", json: `{"ref":"0000000000000000000000000000000000000000"}`, ref: "0000000000000000000000000000000000000000"},
+		{event: "create", json: `{"ref":"0000000000000000000000000000000000000000"}`, ref: "0000000000000000000000000000000000000000"},
+		{event: "workflow_dispatch", json: `{"ref":"0000000000000000000000000000000000000000"}`, ref: "0000000000000000000000000000000000000000"},
+		{event: "delete", json: `{"repository":{"default_branch": "main"}}`, ref: "refs/heads/main"},
+		{event: "pull_request", json: `{"number":123}`, ref: "refs/pull/123/merge"},
+		{event: "pull_request_review", json: `{"number":123}`, ref: "refs/pull/123/merge"},
+		{event: "pull_request_review_comment", json: `{"number":123}`, ref: "refs/pull/123/merge"},
+		{event: "pull_request_target", json: `{"pull_request":{"base":{"ref": "main"}}}`, ref: "refs/heads/main"},
+		{event: "deployment", json: `{"deployment": {"ref": "tag-name"}}`, ref: "tag-name"},
+		{event: "deployment_status", json: `{"deployment": {"ref": "tag-name"}}`, ref: "tag-name"},
+		{event: "release", json: `{"release": {"tag_name": "tag-name"}}`, ref: "tag-name"},
+	}
+
+	for _, data := range table {
+		data := data
+		t.Run(data.event, func(t *testing.T) {
+			rc := &RunContext{
+				EventJSON: data.json,
+				Config: &Config{
+					EventName: data.event,
+					Workdir:   "",
+				},
+				Run: &model.Run{
+					Workflow: &model.Workflow{
+						Name: "GitHubContextTest",
+					},
+				},
+			}
+
+			ghc := rc.getGithubContext(context.Background())
+
+			assert.Equal(t, data.ref, ghc.Ref)
+		})
+	}
+}
+
 func createIfTestRunContext(jobs map[string]*model.Job) *RunContext {
 	rc := &RunContext{
 		Config: &Config{