From 4296b17545a579ee10b12ffdc50d69819afe8a0d Mon Sep 17 00:00:00 2001
From: Bogdan Drutu <bogdandrutu@gmail.com>
Date: Sat, 9 Aug 2025 22:38:57 -0700
Subject: [PATCH] Avoid unnecessary buffer copy when JSON marshal fails.

Signed-off-by: Bogdan Drutu <bogdandrutu@gmail.com>
---
 .chloggen/json-marshal.yaml | 25 +++++++++++++++++++++++++
 pdata/plog/json.go          |  5 ++++-
 pdata/pmetric/json.go       |  5 ++++-
 pdata/pprofile/json.go      |  5 ++++-
 pdata/ptrace/json.go        |  5 ++++-
 5 files changed, 41 insertions(+), 4 deletions(-)
 create mode 100644 .chloggen/json-marshal.yaml

diff --git a/.chloggen/json-marshal.yaml b/.chloggen/json-marshal.yaml
new file mode 100644
index 000000000000..4b8af1fcec66
--- /dev/null
+++ b/.chloggen/json-marshal.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: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. otlpreceiver)
+component: pdata
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Avoid unnecessary buffer copy when JSON marshal fails.
+
+# One or more tracking issues or pull requests related to the change
+issues: [13598]
+
+# (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, user]
diff --git a/pdata/plog/json.go b/pdata/plog/json.go
index ac66c96c76ef..ea449870311c 100644
--- a/pdata/plog/json.go
+++ b/pdata/plog/json.go
@@ -18,7 +18,10 @@ func (*JSONMarshaler) MarshalLogs(ld Logs) ([]byte, error) {
 	dest := json.BorrowStream(nil)
 	defer json.ReturnStream(dest)
 	ld.marshalJSONStream(dest)
-	return slices.Clone(dest.Buffer()), dest.Error()
+	if dest.Error() != nil {
+		return nil, dest.Error()
+	}
+	return slices.Clone(dest.Buffer()), nil
 }
 
 var _ Unmarshaler = (*JSONUnmarshaler)(nil)
diff --git a/pdata/pmetric/json.go b/pdata/pmetric/json.go
index 904e0860c8a6..61113180c205 100644
--- a/pdata/pmetric/json.go
+++ b/pdata/pmetric/json.go
@@ -20,7 +20,10 @@ func (*JSONMarshaler) MarshalMetrics(md Metrics) ([]byte, error) {
 	dest := json.BorrowStream(nil)
 	defer json.ReturnStream(dest)
 	md.marshalJSONStream(dest)
-	return slices.Clone(dest.Buffer()), dest.Error()
+	if dest.Error() != nil {
+		return nil, dest.Error()
+	}
+	return slices.Clone(dest.Buffer()), nil
 }
 
 // JSONUnmarshaler unmarshals OTLP/JSON formatted-bytes to Metrics.
diff --git a/pdata/pprofile/json.go b/pdata/pprofile/json.go
index d1997fd7664b..bfb66e2ce61f 100644
--- a/pdata/pprofile/json.go
+++ b/pdata/pprofile/json.go
@@ -18,7 +18,10 @@ func (*JSONMarshaler) MarshalProfiles(pd Profiles) ([]byte, error) {
 	dest := json.BorrowStream(nil)
 	defer json.ReturnStream(dest)
 	pd.marshalJSONStream(dest)
-	return slices.Clone(dest.Buffer()), dest.Error()
+	if dest.Error() != nil {
+		return nil, dest.Error()
+	}
+	return slices.Clone(dest.Buffer()), nil
 }
 
 // JSONUnmarshaler unmarshals OTLP/JSON formatted-bytes to pprofile.Profiles.
diff --git a/pdata/ptrace/json.go b/pdata/ptrace/json.go
index 07a7d6b37945..94cd6328a906 100644
--- a/pdata/ptrace/json.go
+++ b/pdata/ptrace/json.go
@@ -18,7 +18,10 @@ func (*JSONMarshaler) MarshalTraces(td Traces) ([]byte, error) {
 	dest := json.BorrowStream(nil)
 	defer json.ReturnStream(dest)
 	td.marshalJSONStream(dest)
-	return slices.Clone(dest.Buffer()), dest.Error()
+	if dest.Error() != nil {
+		return nil, dest.Error()
+	}
+	return slices.Clone(dest.Buffer()), nil
 }
 
 // JSONUnmarshaler unmarshals OTLP/JSON formatted-bytes to Traces.