dockercompose: watch service env files (#5750)

* dockercompose: watch service env files

* dockercompose: base relative env files against project path

internal/tiltfile/docker_compose.go

@@ -145,6 +145,15 @@ func (s *tiltfileState) dockerCompose(thread *starlark.Thread, fn *starlark.Buil
 			return nil, err
 		}
 		svc.Options = s.dcResOptions[svc.Name]
+		for _, f := range svc.ServiceConfig.EnvFile {
+			if !filepath.IsAbs(f) {
+				f = filepath.Join(project.ProjectPath, f)
+			}
+			err = io.RecordReadPath(thread, io.WatchFileOnly, f)
+			if err != nil {
+				return nil, err
+			}
+		}
 		s.dcByName[svc.Name] = svc
 	}
 

internal/tiltfile/tiltfile_docker_compose_test.go

@@ -147,6 +147,30 @@ func TestDockerComposeEnvFile(t *testing.T) {
 	f.assertConfigFiles(expectedConfFiles...)
 }
 
+func TestDockerComposeServiceEnvFile(t *testing.T) {
+	f := newFixture(t)
+
+	f.file("docker-compose.yml", `services:
+  bar:
+    image: bar-image
+    env_file:
+      - bar.env
+`)
+	f.file("bar.env", "BAR_PORT=4000\n")
+	f.file("Tiltfile", "docker_compose('docker-compose.yml')")
+
+	f.load()
+	f.assertDcManifest("bar")
+
+	expectedConfFiles := []string{
+		"Tiltfile",
+		".tiltignore",
+		"docker-compose.yml",
+		"bar.env",
+	}
+	f.assertConfigFiles(expectedConfFiles...)
+}
+
 func TestDockerComposeConflict(t *testing.T) {
 	f := newFixture(t)