[processor/transform] Fix panic when transforming span events (open-t…

…elemetry#16622)

* Fix bug

* changelog

.chloggen/tp-fix-spanevent-bug.yaml

@@ -0,0 +1,16 @@
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: processor/transform
+
+# A brief description of the change. Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Fix issue where collector would panic under certain conditions if the transformprocessor was configured to transform span events.
+
+# One or more tracking issues related to the change
+issues: [16622]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:

processor/transformprocessor/internal/common/traces.go

@@ -78,7 +78,7 @@ func (s spanEventStatements) ConsumeTraces(ctx context.Context, td ptrace.Traces
  span := spans.At(k)
  spanEvents := span.Events()
  for n := 0; n < spanEvents.Len(); n++ {
- tCtx := ottlspanevent.NewTransformContext(spanEvents.At(k), span, sspans.Scope(), rspans.Resource())
+ tCtx := ottlspanevent.NewTransformContext(spanEvents.At(n), span, sspans.Scope(), rspans.Resource())
  for _, statement := range s {
  _, _, err := statement.Execute(ctx, tCtx)
  if err != nil {

processor/transformprocessor/internal/traces/processor_test.go

@@ -370,6 +370,36 @@ func Test_ProcessTraces_TraceContext(t *testing.T) {
  }
 }
 
+func Test_ProcessTraces_SpanEventContext(t *testing.T) {
+ tests := []struct {
+ statement string
+ want func(td ptrace.Traces)
+ }{
+ {
+ statement: `set(attributes["test"], "pass") where name == "eventA"`,
+ want: func(td ptrace.Traces) {
+ td.ResourceSpans().At(0).ScopeSpans().At(0).Spans().At(0).Events().At(0).Attributes().PutStr("test", "pass")
+ },
+ },
+ }
+
+ for _, tt := range tests {
+ t.Run(tt.statement, func(t *testing.T) {
+ td := constructTraces()
+ processor, err := NewProcessor(nil, []common.ContextStatements{{Context: "spanevent", Statements: []string{tt.statement}}}, componenttest.NewNopTelemetrySettings())
+ assert.NoError(t, err)
+
+ _, err = processor.ProcessTraces(context.Background(), td)
+ assert.NoError(t, err)
+
+ exTd := constructTraces()
+ tt.want(exTd)
+
+ assert.Equal(t, exTd, td)
+ })
+ }
+}
+
 func Test_ProcessTraces_MixContext(t *testing.T) {
  tests := []struct {
  name string
@@ -617,6 +647,8 @@ func fillSpanOne(span ptrace.Span) {
  status := span.Status()
  status.SetCode(ptrace.StatusCodeError)
  status.SetMessage("status-cancelled")
+ event := span.Events().AppendEmpty()
+ event.SetName("eventA")
 }
 
 func fillSpanTwo(span ptrace.Span) {
@@ -635,4 +667,6 @@ func fillSpanTwo(span ptrace.Span) {
  status := span.Status()
  status.SetCode(ptrace.StatusCodeError)
  status.SetMessage("status-cancelled")
+ event := span.Events().AppendEmpty()
+ event.SetName("eventB")
 }