[v2][adjuster] Add warning to span links adjuster (#6381)

## Which problem is this PR solving?
- Towards #6344 

## Description of the changes
- Add a warning to the `SpanLinks` adjuster when there is a bad span
link to match the behaviour of the v1 adjuster
(https://github.com/jaegertracing/jaeger/blob/main/model/adjuster/bad_span_references.go#L40)

## How was this change tested?
- Updated unit tests

## Checklist
- [x] I have read
https://github.com/jaegertracing/jaeger/blob/master/CONTRIBUTING_GUIDELINES.md
- [x] I have signed all commits
- [x] I have added unit tests for the new functionality
- [x] I have run lint and test steps successfully
  - for `jaeger`: `make lint test`
  - for `jaeger-ui`: `npm run lint` and `npm run test`

---------

Signed-off-by: Mahad Zaryab <[email protected]>

Author: mahadzaryab1

cmd/query/app/querysvc/adjuster/spanlinks.go

@@ -5,6 +5,12 @@ package adjuster
 
 import (
 	"go.opentelemetry.io/collector/pdata/ptrace"
+
+	"github.com/jaegertracing/jaeger/internal/jptrace"
+)
+
+const (
+	invalidSpanLinkWarning = "Invalid span link removed"
 )
 
 // SpanLinks creates an adjuster that removes span links with empty trace IDs.
@@ -40,6 +46,8 @@ func (la LinksAdjuster) adjust(span ptrace.Span) {
 		if la.valid(link) {
 			newLink := validLinks.AppendEmpty()
 			link.CopyTo(newLink)
+		} else {
+			jptrace.AddWarning(span, invalidSpanLinkWarning)
 		}
 	}
 	validLinks.CopyTo(span.Links())

cmd/query/app/querysvc/adjuster/spanlinks_test.go

@@ -10,6 +10,8 @@ import (
 	"github.com/stretchr/testify/require"
 	"go.opentelemetry.io/collector/pdata/pcommon"
 	"go.opentelemetry.io/collector/pdata/ptrace"
+
+	"github.com/jaegertracing/jaeger/internal/jptrace"
 )
 
 func TestLinksAdjuster(t *testing.T) {
@@ -21,19 +23,32 @@ func TestLinksAdjuster(t *testing.T) {
 	scopeSpans.Spans().AppendEmpty()
 
 	// span with empty traceID link
-	spanA := scopeSpans.Spans().AppendEmpty()
-	spanA.Links().AppendEmpty().SetTraceID(pcommon.NewTraceIDEmpty())
+	spanB := scopeSpans.Spans().AppendEmpty()
+	spanB.Links().AppendEmpty().SetTraceID(pcommon.NewTraceIDEmpty())
 
 	// span with 2 non-empty traceID links and 1 empty (or zero) traceID link
-	spanB := scopeSpans.Spans().AppendEmpty()
-	spanB.Links().AppendEmpty().SetTraceID(pcommon.TraceID([]byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}))
-	spanB.Links().AppendEmpty().SetTraceID(pcommon.TraceID([]byte{0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0}))
-	spanB.Links().AppendEmpty().SetTraceID(pcommon.TraceID([]byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}))
+	spanC := scopeSpans.Spans().AppendEmpty()
+	spanC.Links().AppendEmpty().SetTraceID(pcommon.TraceID([]byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}))
+	spanC.Links().AppendEmpty().SetTraceID(pcommon.TraceID([]byte{0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0}))
+	spanC.Links().AppendEmpty().SetTraceID(pcommon.TraceID([]byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}))
 
 	err := SpanLinks().Adjust(traces)
 	spans := traces.ResourceSpans().At(0).ScopeSpans().At(0).Spans()
 	require.NoError(t, err)
-	assert.Equal(t, 0, spans.At(0).Links().Len())
-	assert.Equal(t, 0, spans.At(1).Links().Len())
-	assert.Equal(t, 2, spans.At(2).Links().Len())
+
+	gotSpansA := spans.At(0)
+	assert.Equal(t, 0, gotSpansA.Links().Len())
+	assert.Empty(t, jptrace.GetWarnings(gotSpansA))
+
+	gotSpansB := spans.At(1)
+	assert.Equal(t, 0, gotSpansB.Links().Len())
+	spanBWarnings := jptrace.GetWarnings(gotSpansB)
+	assert.Len(t, spanBWarnings, 1)
+	assert.Equal(t, "Invalid span link removed", spanBWarnings[0])
+
+	gotSpansC := spans.At(2)
+	assert.Equal(t, 2, gotSpansC.Links().Len())
+	spanCWarnings := jptrace.GetWarnings(gotSpansC)
+	assert.Len(t, spanCWarnings, 1)
+	assert.Equal(t, "Invalid span link removed", spanCWarnings[0])
 }