In pip vendored dependencies, show clear message if FF is missing fro…

…m requirements.txt.

PiperOrigin-RevId: 569326761
Change-Id: Ieda33142f8a3b4db068d0aec86d7fd3b8e2e9203

builders/python/acceptance/gcf_test.go

@@ -118,6 +118,12 @@ func TestFailures(t *testing.T) {
 			Env:       []string{"GOOGLE_SKIP_FRAMEWORK_INJECTION=True"},
 			MustMatch: "skipping automatic framework injection has been enabled",
 		},
+		{
+			Name:      "use pip vendored deps - framework not vendored",
+			App:       "without_framework",
+			Env:       []string{"GOOGLE_VENDOR_PIP_DEPENDENCIES=vendor"},
+			MustMatch: "Vendored dependencies detected, please add functions-framework to requirements.txt and download it using pip",
+		},
 	}
 
 	for _, tc := range acceptance.FilterFailureTests(t, testCases) {

cmd/python/functions_framework/main.go

@@ -83,6 +83,9 @@ func buildFn(ctx *gcp.Context) error {
 			return fmt.Errorf("clearing layer %q: %w", l.Name, err)
 		}
 	} else {
+		if _, isVendored := os.LookupEnv(python.VendorPipDepsEnv); isVendored {
+			return gcp.UserErrorf("Vendored dependencies detected, please add functions-framework to requirements.txt and download it using pip")
+		}
 		ctx.Logf("Handling functions without dependency on functions-framework.")
 		if err := cloudfunctions.AssertFrameworkInjectionAllowed(); err != nil {
 			return err