feat(util/component): add Declared.SkipFutureMerges

util/cmd/cmd.go

@@ -120,12 +120,16 @@ func tryRun(requests []func(*component.DepRequests)) error {
 // and does not block until shutdown.
 // Returns as soon as startup completes to allow the caller to orchestrate integration tests.
 func MockStartup(ctx context.Context, requests []func(*component.DepRequests)) component.ApiMap {
+	return MockStartupWithCliArgs(ctx, requests, []string{})
+}
+
+func MockStartupWithCliArgs(ctx context.Context, requests []func(*component.DepRequests), cliArgs []string) component.ApiMap {
 	components := component.ResolveList(requests)
 
 	fs := new(pflag.FlagSet)
 	setupFlags(components, fs)
 
-	if err := fs.Parse([]string{}); err != nil {
+	if err := fs.Parse(cliArgs); err != nil {
 		panic(err)
 	}
 

util/cmd/cmd_test.go

@@ -0,0 +1,217 @@
+// Copyright 2024 The Podseidon Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cmd_test
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"k8s.io/utils/ptr"
+
+	"github.com/kubewharf/podseidon/util/cmd"
+	"github.com/kubewharf/podseidon/util/component"
+	"github.com/kubewharf/podseidon/util/util"
+)
+
+var TestingT = component.Declare(
+	func(_ *testing.T) string { return "testing" },
+	func(_ *testing.T, _ *flag.FlagSet) util.Empty { return util.Empty{} },
+	func(_ *testing.T, _ *component.DepRequests) util.Empty { return util.Empty{} },
+	func(_ context.Context, _ *testing.T, _ util.Empty, _ util.Empty) (*util.Empty, error) {
+		return &util.Empty{}, nil
+	},
+	component.Lifecycle[*testing.T, util.Empty, util.Empty, util.Empty]{
+		Start:        nil,
+		Join:         nil,
+		HealthChecks: nil,
+	},
+	func(d *component.Data[*testing.T, util.Empty, util.Empty, util.Empty]) *testing.T { return d.Args },
+)
+
+var Counter = component.Declare[CounterArgs, CounterOptions, CounterDeps, CounterState, CounterApi](
+	func(args CounterArgs) string { return args.Name },
+	func(_ CounterArgs, fs *flag.FlagSet) CounterOptions {
+		return CounterOptions{
+			Multiplier:         fs.Int("multiplier", 10, ""),
+			ExpectMutableField: fs.String("expect", "", ""),
+		}
+	},
+	func(_ CounterArgs, reqs *component.DepRequests) CounterDeps {
+		return CounterDeps{Testing: component.DepPtr(reqs, TestingT(nil))}
+	},
+	func(_ context.Context, _ CounterArgs, _ CounterOptions, _ CounterDeps) (*CounterState, error) {
+		return &CounterState{mutableField: []string{}}, nil
+	},
+	component.Lifecycle[CounterArgs, CounterOptions, CounterDeps, CounterState]{
+		Start: func(_ context.Context, _ *CounterArgs, options *CounterOptions, deps *CounterDeps, state *CounterState) error {
+			assert.Equalf(
+				deps.Testing.Get(),
+				*options.ExpectMutableField,
+				strings.Join(state.mutableField, ","),
+				"start is called strictly after all init",
+			)
+			return nil
+		},
+		Join:         nil,
+		HealthChecks: nil,
+	},
+	func(d *component.Data[CounterArgs, CounterOptions, CounterDeps, CounterState]) CounterApi {
+		return CounterApi{multiplier: *d.Options.Multiplier, state: d.State}
+	},
+)
+
+type CounterArgs struct {
+	Name string
+}
+
+type CounterOptions struct {
+	Multiplier         *int
+	ExpectMutableField *string
+}
+
+type CounterDeps struct {
+	Testing component.Dep[*testing.T]
+}
+
+type CounterState struct {
+	mutableField []string
+}
+
+type CounterApi struct {
+	multiplier int
+	state      *CounterState
+}
+
+func (api CounterApi) Update(value int) {
+	api.state.mutableField = append(api.state.mutableField, fmt.Sprint(api.multiplier*value))
+}
+
+// the pointer is intentionally added to trigger panic when it is unused despite expected to be used.
+func Mutator(mutatorArgs MutatorArgs, counterDepName *string, mutatorDepNames *[]string) component.Declared[util.Empty] {
+	return component.Declare(
+		func(args MutatorArgs) string { return args.Name },
+		func(_ MutatorArgs, fs *flag.FlagSet) MutatorOptions {
+			return MutatorOptions{Value: fs.Int("value", 0, "")}
+		},
+		func(_ MutatorArgs, reqs *component.DepRequests) MutatorDeps {
+			counterDep := component.DepPtr(reqs, Counter(CounterArgs{Name: *counterDepName}))
+
+			for _, mutatorDepName := range *mutatorDepNames {
+				component.DepPtr(reqs, Mutator(MutatorArgs{Name: mutatorDepName}, nil, nil))
+			}
+
+			return MutatorDeps{
+				Counter: counterDep,
+			}
+		},
+		func(_ context.Context, _ MutatorArgs, options MutatorOptions, deps MutatorDeps) (*util.Empty, error) {
+			deps.Counter.Get().Update(*options.Value)
+			return &util.Empty{}, nil
+		},
+		component.Lifecycle[MutatorArgs, MutatorOptions, MutatorDeps, util.Empty]{
+			Start:        nil,
+			Join:         nil,
+			HealthChecks: nil,
+		},
+		func(*component.Data[MutatorArgs, MutatorOptions, MutatorDeps, util.Empty]) util.Empty {
+			return util.Empty{}
+		},
+	)(mutatorArgs)
+}
+
+type MutatorArgs struct {
+	Name string
+}
+
+type MutatorOptions struct {
+	Value *int
+}
+
+type MutatorDeps struct {
+	Counter component.Dep[CounterApi]
+}
+
+func TestDeduplication(t *testing.T) {
+	t.Parallel()
+
+	cmd.MockStartupWithCliArgs(
+		context.Background(),
+		[]func(*component.DepRequests){
+			component.RequireDep(TestingT(t).SkipFutureMerges()),
+			component.RequireDep(Mutator(MutatorArgs{
+				Name: "mutator1",
+			}, ptr.To("counter1"), ptr.To[[]string](nil))),
+			component.RequireDep(Mutator(MutatorArgs{
+				Name: "mutator2",
+			}, ptr.To("counter1"), ptr.To([]string{"mutator1"}))),
+			component.RequireDep(Mutator(MutatorArgs{
+				Name: "mutator3",
+			}, ptr.To("counter2"), ptr.To([]string{"mutator1"}))),
+		},
+		[]string{
+			"--counter1-multiplier=100",
+			"--counter1-expect=100,200",
+			"--counter2-expect=30",
+			"--mutator1-value=1",
+			"--mutator2-value=2",
+			"--mutator3-value=3",
+		},
+	)
+}
+
+func Cyclic(name string, deps ...func() component.Declared[util.Empty]) component.Declared[util.Empty] {
+	return component.Declare(
+		func(_ util.Empty) string { return name },
+		func(_ util.Empty, _ *flag.FlagSet) util.Empty { return util.Empty{} },
+		func(_ util.Empty, reqs *component.DepRequests) util.Empty {
+			for _, dep := range deps {
+				component.DepPtr(reqs, dep())
+			}
+
+			return util.Empty{}
+		},
+		func(_ context.Context, _ util.Empty, _ util.Empty, _ util.Empty) (*util.Empty, error) {
+			return &util.Empty{}, nil
+		},
+		component.Lifecycle[util.Empty, util.Empty, util.Empty, util.Empty]{
+			Start:        nil,
+			Join:         nil,
+			HealthChecks: nil,
+		},
+		func(d *component.Data[util.Empty, util.Empty, util.Empty, util.Empty]) util.Empty { return d.Args },
+	)(util.Empty{})
+}
+
+func Cyclic1() component.Declared[util.Empty] { return Cyclic("cyclic1", Cyclic2) }
+func Cyclic2() component.Declared[util.Empty] { return Cyclic("cyclic2", Cyclic1) }
+
+func TestCyclicDependency(t *testing.T) {
+	t.Parallel()
+
+	assert.PanicsWithValue(t, `cyclic dependency detected: "cyclic1"`, func() {
+		cmd.MockStartupWithCliArgs(
+			context.Background(),
+			[]func(*component.DepRequests){
+				component.RequireDep(Cyclic1()),
+				component.RequireDep(Cyclic2()),
+			},
+			[]string{},
+		)
+	})
+}