[apache#28126] plumb coder errors with better context.

sdks/go/pkg/beam/runners/prism/internal/coders.go

@@ -53,9 +53,12 @@ func isLeafCoder(c *pipepb.Coder) bool {
 //
 // PCollection coders are not inherently WindowValueCoder wrapped, and they are added by the runner
 // for crossing the FnAPI boundary at data sources and data sinks.
-func makeWindowedValueCoder(pID string, comps *pipepb.Components, coders map[string]*pipepb.Coder) string {
+func makeWindowedValueCoder(pID string, comps *pipepb.Components, coders map[string]*pipepb.Coder) (string, error) {
 	col := comps.GetPcollections()[pID]
-	cID := lpUnknownCoders(col.GetCoderId(), coders, comps.GetCoders())
+	cID, err := lpUnknownCoders(col.GetCoderId(), coders, comps.GetCoders())
+	if err != nil {
+		return "", fmt.Errorf("makeWindowedValueCoder: couldn't process coder for pcollection %q %v: %w", pID, prototext.Format(col), err)
+	}
 	wcID := comps.GetWindowingStrategies()[col.GetWindowingStrategyId()].GetWindowCoderId()
 
 	// The runner needs to be defensive, and tell the SDK to Length Prefix
@@ -73,7 +76,7 @@ func makeWindowedValueCoder(pID string, comps *pipepb.Components, coders map[str
 	}
 	// Populate the coders to send with the new windowed value coder.
 	coders[wvcID] = wInC
-	return wvcID
+	return wvcID, nil
 }
 
 // makeWindowCoders makes the coder pair but behavior is ultimately determined by the strategy's windowFn.
@@ -94,22 +97,22 @@ func makeWindowCoders(wc *pipepb.Coder) (exec.WindowDecoder, exec.WindowEncoder)
 // lpUnknownCoders takes a coder, and populates coders with any new coders
 // coders that the runner needs to be safe, and speedy.
 // It returns either the passed in coder id, or the new safe coder id.
-func lpUnknownCoders(cID string, bundle, base map[string]*pipepb.Coder) string {
+func lpUnknownCoders(cID string, bundle, base map[string]*pipepb.Coder) (string, error) {
 	// First check if we've already added the LP version of this coder to coders already.
 	lpcID := cID + "_lp"
 	// Check if we've done this one before.
 	if _, ok := bundle[lpcID]; ok {
-		return lpcID
+		return lpcID, nil
 	}
 	// All coders in the coders map have been processed.
 	if _, ok := bundle[cID]; ok {
-		return cID
+		return cID, nil
 	}
 	// Look up the canonical location.
 	c, ok := base[cID]
 	if !ok {
 		// We messed up somewhere.
-		panic(fmt.Sprint("unknown coder id:", cID))
+		return "", fmt.Errorf("lpUnknownCoders: coder %q not present in base map", cID)
 	}
 	// Add the original coder to the coders map.
 	bundle[cID] = c
@@ -124,7 +127,7 @@ func lpUnknownCoders(cID string, bundle, base map[string]*pipepb.Coder) string {
 			ComponentCoderIds: []string{cID},
 		}
 		bundle[lpcID] = lpc
-		return lpcID
+		return lpcID, nil
 	}
 	// We know we have a composite, so if we count this as a leaf, move everything to
 	// the coders map.
@@ -133,12 +136,15 @@ func lpUnknownCoders(cID string, bundle, base map[string]*pipepb.Coder) string {
 		for _, cc := range c.GetComponentCoderIds() {
 			bundle[cc] = base[cc]
 		}
-		return cID
+		return cID, nil
 	}
 	var needNewComposite bool
 	var comps []string
-	for _, cc := range c.GetComponentCoderIds() {
-		rcc := lpUnknownCoders(cc, bundle, base)
+	for i, cc := range c.GetComponentCoderIds() {
+		rcc, err := lpUnknownCoders(cc, bundle, base)
+		if err != nil {
+			return "", fmt.Errorf("lpUnknownCoders: couldn't handle component %d %q of %q %v:\n%w", i, cc, cID, prototext.Format(c), err)
+		}
 		if cc != rcc {
 			needNewComposite = true
 		}
@@ -150,9 +156,9 @@ func lpUnknownCoders(cID string, bundle, base map[string]*pipepb.Coder) string {
 			ComponentCoderIds: comps,
 		}
 		bundle[lpcID] = lpc
-		return lpcID
+		return lpcID, nil
 	}
-	return cID
+	return cID, nil
 }
 
 // reconcileCoders ensures that the bundle coders are primed with initial coders from

sdks/go/pkg/beam/runners/prism/internal/coders_test.go

@@ -62,7 +62,7 @@ func Test_isLeafCoder(t *testing.T) {
 func Test_makeWindowedValueCoder(t *testing.T) {
 	coders := map[string]*pipepb.Coder{}
 
-	gotID := makeWindowedValueCoder("testPID", &pipepb.Components{
+	gotID, err := makeWindowedValueCoder("testPID", &pipepb.Components{
 		Pcollections: map[string]*pipepb.PCollection{
 			"testPID": {CoderId: "testCoderID"},
 		},
@@ -74,7 +74,9 @@ func Test_makeWindowedValueCoder(t *testing.T) {
 			},
 		},
 	}, coders)
-
+	if err != nil {
+		t.Errorf("makeWindowedValueCoder(...) = error %v, want nil", err)
+	}
 	if gotID == "" {
 		t.Errorf("makeWindowedValueCoder(...) = %v, want non-empty", gotID)
 	}

sdks/go/pkg/beam/runners/prism/internal/execute.go

@@ -297,13 +297,19 @@ func executePipeline(ctx context.Context, wk *worker.W, j *jobservices.Job) erro
 }
 
 func collectionPullDecoder(coldCId string, coders map[string]*pipepb.Coder, comps *pipepb.Components) func(io.Reader) []byte {
-	cID := lpUnknownCoders(coldCId, coders, comps.GetCoders())
+	cID, err := lpUnknownCoders(coldCId, coders, comps.GetCoders())
+	if err != nil {
+		panic(err)
+	}
 	return pullDecoder(coders[cID], coders)
 }
 
 func getWindowValueCoders(comps *pipepb.Components, col *pipepb.PCollection, coders map[string]*pipepb.Coder) (exec.WindowDecoder, exec.WindowEncoder) {
 	ws := comps.GetWindowingStrategies()[col.GetWindowingStrategyId()]
-	wcID := lpUnknownCoders(ws.GetWindowCoderId(), coders, comps.GetCoders())
+	wcID, err := lpUnknownCoders(ws.GetWindowCoderId(), coders, comps.GetCoders())
+	if err != nil {
+		panic(err)
+	}
 	return makeWindowCoders(coders[wcID])
 }
 

sdks/go/pkg/beam/runners/prism/internal/handlerunner.go

@@ -162,9 +162,18 @@ func (h *runner) ExecuteTransform(stageID, tid string, t *pipepb.PTransform, com
 		coders := map[string]*pipepb.Coder{}
 
 		// TODO assert this is a KV. It's probably fine, but we should fail anyway.
-		wcID := lpUnknownCoders(ws.GetWindowCoderId(), coders, comps.GetCoders())
-		kcID := lpUnknownCoders(kvc.GetComponentCoderIds()[0], coders, comps.GetCoders())
-		ecID := lpUnknownCoders(kvc.GetComponentCoderIds()[1], coders, comps.GetCoders())
+		wcID, err := lpUnknownCoders(ws.GetWindowCoderId(), coders, comps.GetCoders())
+		if err != nil {
+			panic(fmt.Errorf("ExecuteTransform[GBK] stage %v, transform %q %v: couldn't process window coder:\n%w", stageID, tid, prototext.Format(t), err))
+		}
+		kcID, err := lpUnknownCoders(kvc.GetComponentCoderIds()[0], coders, comps.GetCoders())
+		if err != nil {
+			panic(fmt.Errorf("ExecuteTransform[GBK] stage %v, transform %q %v: couldn't process key coder:\n%w", stageID, tid, prototext.Format(t), err))
+		}
+		ecID, err := lpUnknownCoders(kvc.GetComponentCoderIds()[1], coders, comps.GetCoders())
+		if err != nil {
+			panic(fmt.Errorf("ExecuteTransform[GBK] stage %v, transform %q %v: couldn't process value coder:\n%w", stageID, tid, prototext.Format(t), err))
+		}
 		reconcileCoders(coders, comps.GetCoders())
 
 		wc := coders[wcID]

sdks/go/pkg/beam/runners/prism/internal/stage.go

@@ -33,6 +33,7 @@ import (
 	"github.com/apache/beam/sdks/v2/go/pkg/beam/runners/prism/internal/worker"
 	"golang.org/x/exp/maps"
 	"golang.org/x/exp/slog"
+	"google.golang.org/protobuf/encoding/prototext"
 	"google.golang.org/protobuf/proto"
 )
 
@@ -290,9 +291,12 @@ func buildDescriptor(stg *stage, comps *pipepb.Components, wk *worker.W) error {
 	sink2Col := map[string]string{}
 	col2Coders := map[string]engine.PColInfo{}
 	for _, o := range stg.outputs {
-		wOutCid := makeWindowedValueCoder(o.global, comps, coders)
-		sinkID := o.transform + "_" + o.local
 		col := comps.GetPcollections()[o.global]
+		wOutCid, err := makeWindowedValueCoder(o.global, comps, coders)
+		if err != nil {
+			return fmt.Errorf("buildDescriptor: failed to handle coder on stage %v for output %+v, pcol %q %v:\n%w", stg.ID, o, o.global, prototext.Format(col), err)
+		}
+		sinkID := o.transform + "_" + o.local
 		ed := collectionPullDecoder(col.GetCoderId(), coders, comps)
 		wDec, wEnc := getWindowValueCoders(comps, col, coders)
 		sink2Col[sinkID] = o.global
@@ -311,7 +315,10 @@ func buildDescriptor(stg *stage, comps *pipepb.Components, wk *worker.W) error {
 	for _, si := range stg.sideInputs {
 		col := comps.GetPcollections()[si.global]
 		oCID := col.GetCoderId()
-		nCID := lpUnknownCoders(oCID, coders, comps.GetCoders())
+		nCID, err := lpUnknownCoders(oCID, coders, comps.GetCoders())
+		if err != nil {
+			return fmt.Errorf("buildDescriptor: failed to handle coder on stage %v for side input %+v, pcol %q %v:\n%w", stg.ID, si, si.global, prototext.Format(col), err)
+		}
 
 		sides = append(sides, si.global)
 		if oCID != nCID {
@@ -339,9 +346,13 @@ func buildDescriptor(stg *stage, comps *pipepb.Components, wk *worker.W) error {
 	// This id is directly used for the source, but this also copies
 	// coders used by side inputs to the coders map for the bundle, so
 	// needs to be run for every ID.
-	wInCid := makeWindowedValueCoder(stg.primaryInput, comps, coders)
 
 	col := comps.GetPcollections()[stg.primaryInput]
+	wInCid, err := makeWindowedValueCoder(stg.primaryInput, comps, coders)
+	if err != nil {
+		return fmt.Errorf("buildDescriptor: failed to handle coder on stage %v for primary input, pcol %q %v:\n%w", stg.ID, stg.primaryInput, prototext.Format(col), err)
+	}
+
 	ed := collectionPullDecoder(col.GetCoderId(), coders, comps)
 	wDec, wEnc := getWindowValueCoders(comps, col, coders)
 	inputInfo := engine.PColInfo{