Change SetLink signature to return the link's ID, not update (#14031)

Part of
#14016

Author: dmathieu

.chloggen/setlink-immutable.yaml

@@ -0,0 +1,25 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: breaking
+
+# The name of the component, or a single word describing the area of concern, (e.g. otlpreceiver)
+component: pdata/pprofile
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Update `SetLink` to return the link's ID rather than update the Sample
+
+# One or more tracking issues or pull requests related to the change
+issues: [14016, 14031]
+
+# (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:
+
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [api]

pdata/pprofile/links.go

@@ -5,43 +5,27 @@ package pprofile // import "go.opentelemetry.io/collector/pdata/pprofile"
 
 import (
 	"errors"
-	"fmt"
 	"math"
 )
 
 var errTooManyLinkTableEntries = errors.New("too many entries in LinkTable")
 
-// SetLink updates a LinkTable and a Sample's LinkIndex to
-// add or update a link.
-func SetLink(table LinkSlice, record Sample, li Link) error {
-	idx := int(record.LinkIndex())
-	if idx > 0 {
-		if idx >= table.Len() {
-			return fmt.Errorf("index value %d out of range for LinkIndex", idx)
-		}
-		mapAt := table.At(idx)
-		if mapAt.Equal(li) {
-			// Link already exists, nothing to do.
-			return nil
-		}
-	}
-
+// SetLink updates a LinkTable, adding or providing a value and returns its
+// index.
+func SetLink(table LinkSlice, li Link) (int32, error) {
 	for j, l := range table.All() {
 		if l.Equal(li) {
 			if j > math.MaxInt32 {
-				return errTooManyLinkTableEntries
+				return 0, errTooManyLinkTableEntries
 			}
-			// Add the index of the existing link to the indices.
-			record.SetLinkIndex(int32(j)) //nolint:gosec // G115 overflow checked
-			return nil
+			return int32(j), nil //nolint:gosec // G115 overflow checked
 		}
 	}
 
 	if table.Len() >= math.MaxInt32 {
-		return errTooManyLinkTableEntries
+		return 0, errTooManyLinkTableEntries
 	}
 
 	li.CopyTo(table.AppendEmpty())
-	record.SetLinkIndex(int32(table.Len() - 1)) //nolint:gosec // G115 overflow checked
-	return nil
+	return int32(table.Len() - 1), nil //nolint:gosec // G115 overflow checked
 }

pdata/pprofile/links_test.go

@@ -18,52 +18,45 @@ func TestSetLink(t *testing.T) {
 	l.SetTraceID(pcommon.TraceID([16]byte{1, 2, 3, 4, 5, 6, 7, 8, 8, 7, 6, 5, 4, 3, 2, 1}))
 	l2 := NewLink()
 	l.SetTraceID(pcommon.TraceID([16]byte{2, 2, 3, 4, 5, 6, 7, 8, 8, 7, 6, 5, 4, 3, 2, 2}))
-	smpl := NewSample()
 
 	// Put a first link
-	require.NoError(t, SetLink(table, smpl, l))
+	idx, err := SetLink(table, l)
+	require.NoError(t, err)
 	assert.Equal(t, 1, table.Len())
-	assert.Equal(t, int32(0), smpl.LinkIndex())
+	assert.Equal(t, int32(0), idx)
 
 	// Put the same link
 	// This should be a no-op.
-	require.NoError(t, SetLink(table, smpl, l))
+	idx, err = SetLink(table, l)
+	require.NoError(t, err)
 	assert.Equal(t, 1, table.Len())
-	assert.Equal(t, int32(0), smpl.LinkIndex())
+	assert.Equal(t, int32(0), idx)
 
 	// Set a new link
 	// This sets the index and adds to the table.
-	require.NoError(t, SetLink(table, smpl, l2))
+	idx, err = SetLink(table, l2)
+	require.NoError(t, err)
 	assert.Equal(t, 2, table.Len())
-	assert.Equal(t, int32(table.Len()-1), smpl.LinkIndex()) //nolint:gosec // G115
+	assert.Equal(t, int32(table.Len()-1), idx) //nolint:gosec // G115
 
 	// Set an existing link
-	require.NoError(t, SetLink(table, smpl, l))
+	idx, err = SetLink(table, l)
+	require.NoError(t, err)
 	assert.Equal(t, 2, table.Len())
-	assert.Equal(t, int32(0), smpl.LinkIndex())
+	assert.Equal(t, int32(0), idx)
 	// Set another existing link
-	require.NoError(t, SetLink(table, smpl, l2))
+	idx, err = SetLink(table, l2)
+	require.NoError(t, err)
 	assert.Equal(t, 2, table.Len())
-	assert.Equal(t, int32(table.Len()-1), smpl.LinkIndex()) //nolint:gosec // G115
-}
-
-func TestSetLinkCurrentTooHigh(t *testing.T) {
-	table := NewLinkSlice()
-	smpl := NewSample()
-	smpl.SetLinkIndex(42)
-
-	err := SetLink(table, smpl, NewLink())
-	require.Error(t, err)
-	assert.Equal(t, 0, table.Len())
-	assert.Equal(t, int32(42), smpl.LinkIndex())
+	assert.Equal(t, int32(table.Len()-1), idx) //nolint:gosec // G115
 }
 
 func BenchmarkSetLink(b *testing.B) {
 	for _, bb := range []struct {
 		name string
 		link Link
 
-		runBefore func(*testing.B, LinkSlice, Sample)
+		runBefore func(*testing.B, LinkSlice)
 	}{
 		{
 			name: "with a new link",
@@ -77,7 +70,7 @@ func BenchmarkSetLink(b *testing.B) {
 				return l
 			}(),
 
-			runBefore: func(_ *testing.B, table LinkSlice, _ Sample) {
+			runBefore: func(_ *testing.B, table LinkSlice) {
 				l := table.AppendEmpty()
 				l.SetTraceID(pcommon.NewTraceIDEmpty())
 			},
@@ -86,8 +79,9 @@ func BenchmarkSetLink(b *testing.B) {
 			name: "with a duplicate link",
 			link: NewLink(),
 
-			runBefore: func(_ *testing.B, table LinkSlice, obj Sample) {
-				require.NoError(b, SetLink(table, obj, NewLink()))
+			runBefore: func(b *testing.B, table LinkSlice) {
+				_, err := SetLink(table, NewLink())
+				require.NoError(b, err)
 			},
 		},
 		{
@@ -98,7 +92,7 @@ func BenchmarkSetLink(b *testing.B) {
 				return l
 			}(),
 
-			runBefore: func(_ *testing.B, table LinkSlice, _ Sample) {
+			runBefore: func(_ *testing.B, table LinkSlice) {
 				for range 100 {
 					table.AppendEmpty()
 				}
@@ -107,17 +101,16 @@ func BenchmarkSetLink(b *testing.B) {
 	} {
 		b.Run(bb.name, func(b *testing.B) {
 			table := NewLinkSlice()
-			obj := NewSample()
 
 			if bb.runBefore != nil {
-				bb.runBefore(b, table, obj)
+				bb.runBefore(b, table)
 			}
 
 			b.ResetTimer()
 			b.ReportAllocs()
 
 			for b.Loop() {
-				_ = SetLink(table, obj, bb.link)
+				_, _ = SetLink(table, bb.link)
 			}
 		})
 	}