feat(cmd): handle ErrEnvNotExist with typed error checking

cmd/deploy.go

@@ -421,6 +421,14 @@ For more options, run 'func deploy --help'`, err)
 	return f.Stamp()
 }
 
+type ErrEnvNotExist struct {
+	Name string
+}
+
+func (e ErrEnvNotExist) Error() string {
+	return fmt.Sprintf("environment variable %q does not exist", e.Name)
+}
+
 // build when flag == 'auto' and the function is out-of-date, or when the
 // flag value is explicitly truthy such as 'true' or '1'.  Error if flag
 // is neither 'auto' nor parseable as a boolean.  Return CLI-specific error

cmd/deploy_test.go

@@ -449,6 +449,20 @@ func TestDeploy_Envs(t *testing.T) {
 	}
 
 	// TODO: create and test typed errors for ErrEnvNotExist etc.
+
+	cmd = NewDeployCmd(NewTestClient())
+	cmd.SetArgs([]string{"--env=DOES_NOT_EXIST-"})
+	err = cmd.Execute()
+
+	var e *ErrEnvNotExist
+	if !errors.As(err, &e) {
+		t.Fatalf("expected ErrEnvNotExist, got '%v'", err)
+	}
+
+	if e.Name != "DOES_NOT_EXIST" {
+		t.Fatalf("expected env name 'DOES_NOT_EXIST', got '%v'", e.Name)
+	}
+
 }
 
 // TestDeploy_FunctionContext ensures that the function contextually relevant

cmd/root.go

@@ -298,13 +298,18 @@ func mergeEnvs(envs []fn.Env, envToUpdate *util.OrderedMap, envToRemove []string
 	}
 
 	for _, name := range envToRemove {
+		found := false
 		for i, envVar := range envs {
 			if *envVar.Name == name {
 				envs = append(envs[:i], envs[i+1:]...)
 				counter++
+				found = true
 				break
 			}
 		}
+		if !found {
+			return nil, 0, &ErrEnvNotExist{Name: name}
+		}
 	}
 
 	errMsg := fn.ValidateEnvs(envs)