fix: skip nil strategies in wait.ForAll (#3032)

* fix: skip nil strategies in wait.ForAll

* fix: handle nil strategies correctly

* fix: lint

Author: mdelapenya

wait/all.go

@@ -3,6 +3,7 @@ package wait
 import (
 	"context"
 	"errors"
+	"reflect"
 	"time"
 )
 
@@ -62,6 +63,13 @@ func (ms *MultiStrategy) WaitUntilReady(ctx context.Context, target StrategyTarg
 	}
 
 	for _, strategy := range ms.Strategies {
+		if strategy == nil || reflect.ValueOf(strategy).IsNil() {
+			// A module could be appending strategies after part of the container initialization,
+			// and use wait.ForAll on a not initialized strategy.
+			// In this case, we just skip the nil strategy.
+			continue
+		}
+
 		strategyCtx := ctx
 
 		// Set default Timeout when strategy implements StrategyTimeout

wait/all_test.go

@@ -124,3 +124,57 @@ func TestMultiStrategy_WaitUntilReady(t *testing.T) {
 		})
 	}
 }
+
+func TestMultiStrategy_handleNils(t *testing.T) {
+	t.Run("nil-strategy", func(t *testing.T) {
+		strategy := ForAll(nil)
+		err := strategy.WaitUntilReady(context.Background(), NopStrategyTarget{})
+		require.NoError(t, err)
+	})
+
+	t.Run("nil-strategy-in-the-middle", func(t *testing.T) {
+		strategy := ForAll(nil, ForLog("docker"))
+		err := strategy.WaitUntilReady(context.Background(), NopStrategyTarget{
+			ReaderCloser: io.NopCloser(bytes.NewReader([]byte("docker"))),
+		})
+		require.NoError(t, err)
+	})
+
+	t.Run("nil-strategy-last", func(t *testing.T) {
+		strategy := ForAll(ForLog("docker"), nil)
+		err := strategy.WaitUntilReady(context.Background(), NopStrategyTarget{
+			ReaderCloser: io.NopCloser(bytes.NewReader([]byte("docker"))),
+		})
+		require.NoError(t, err)
+	})
+
+	t.Run("nil-type-implements-strategy", func(t *testing.T) {
+		var nilStrategy Strategy
+
+		strategy := ForAll(ForLog("docker"), nilStrategy)
+		err := strategy.WaitUntilReady(context.Background(), NopStrategyTarget{
+			ReaderCloser: io.NopCloser(bytes.NewReader([]byte("docker"))),
+		})
+		require.NoError(t, err)
+	})
+
+	t.Run("nil-concrete-value-implements-strategy", func(t *testing.T) {
+		// Create a nil pointer to a type that implements Strategy
+		var nilPointerStrategy *nilWaitStrategy
+		// When we assign it to the interface, the type information is preserved
+		// but the concrete value is nil
+		var strategyInterface Strategy = nilPointerStrategy
+
+		strategy := ForAll(ForLog("docker"), strategyInterface)
+		err := strategy.WaitUntilReady(context.Background(), NopStrategyTarget{
+			ReaderCloser: io.NopCloser(bytes.NewReader([]byte("docker"))),
+		})
+		require.NoError(t, err)
+	})
+}
+
+type nilWaitStrategy struct{}
+
+func (s *nilWaitStrategy) WaitUntilReady(_ context.Context, _ StrategyTarget) error {
+	return nil
+}