If there are no steps, it shouldn't yield a proc

server/procBuilder.go

@@ -80,7 +80,6 @@ func (b *procBuilder) Build() ([]*buildItem, error) {
 				Environ: axis,
 				Name:    sanitizePath(y.Name),
 			}
-			b.Curr.Procs = append(b.Curr.Procs, proc)
 
 			metadata := metadataFromStruct(b.Repo, b.Curr, b.Last, proc, b.Link)
 			environ := b.environmentVariables(metadata, axis)
@@ -113,6 +112,10 @@ func (b *procBuilder) Build() ([]*buildItem, error) {
 
 			ir := b.toInternalRepresentation(parsed, environ, metadata, proc.ID)
 
+			if len(ir.Stages) == 0 {
+				continue
+			}
+
 			item := &buildItem{
 				Proc:      proc,
 				Config:    ir,
@@ -124,6 +127,8 @@ func (b *procBuilder) Build() ([]*buildItem, error) {
 			if item.Labels == nil {
 				item.Labels = map[string]string{}
 			}
+
+			b.Curr.Procs = append(b.Curr.Procs, proc)
 			items = append(items, item)
 			pidSequence++
 		}

server/procBuilder_test.go

@@ -205,6 +205,42 @@ pipeline:
 	}
 }
 
+func TestZeroSteps(t *testing.T) {
+	build := &model.Build{Branch: "dev"}
+
+	b := procBuilder{
+		Repo:  &model.Repo{},
+		Curr:  build,
+		Last:  &model.Build{},
+		Netrc: &model.Netrc{},
+		Secs:  []*model.Secret{},
+		Regs:  []*model.Registry{},
+		Link:  "",
+		Yamls: []*remote.FileMeta{
+			&remote.FileMeta{Data: []byte(`
+skip_clone: true
+pipeline:
+  build:
+    when:
+      branch: notdev
+    image: scratch
+    yyy: ${DRONE_COMMIT_MESSAGE}
+`)},
+		},
+	}
+
+	buildItems, err := b.Build()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(buildItems) != 0 {
+		t.Fatal("Should not generate a build item if there are no steps")
+	}
+	if len(build.Procs) != 0 {
+		t.Fatal("Should not generate a build item if there are no steps")
+	}
+}
+
 func TestTree(t *testing.T) {
 	build := &model.Build{}