fix(logsentry): remap Sentry-reserved "type" context key to "type_"

Sentry reserves the key "type" inside every context object to denote the
context type. A golog value logged under "type" would be consumed as the
"log" context's type instead of shown as data. The removed Event.Extra
map had no reserved keys, so this collision is unique to the context
encoding. Remap "type" -> "type_" when assembling the context (covering
both per-message values and config extra), document it on the Writer, and
test both sources.

Author: ungerik

logsentry/writer.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"maps"
 	"runtime/debug"
 	"strings"
 	"sync"
@@ -109,6 +108,10 @@ func (c *WriterConfig) FlushUnderlying() {
 //
 //	TRACE/DEBUG -> DEBUG, INFO -> INFO, WARN -> WARNING, ERROR -> ERROR, FATAL -> FATAL
 //
+// Sentry reserves the key "type" inside every context object to denote the
+// context type, so a value logged under the key "type" is remapped to "type_"
+// to keep it visible as data (see [copyContextValues]).
+//
 // Example usage through golog:
 //
 //	logger.Error("Database error").Str("query", sql).Err(err).Log()
@@ -160,7 +163,8 @@ func (w *Writer) BeginMessage(config golog.Config, timestamp time.Time, level go
 //   - The accumulated message text
 //   - The mapped Sentry level
 //   - The original timestamp
-//   - All key-value pairs as a "log" context (from both config.extra and values)
+//   - All key-value pairs as a "log" context (from both config.extra and
+//     values), with the Sentry-reserved "type" key remapped to "type_"
 //   - Optional stack trace (if enabled in Sentry options)
 //   - A fingerprint based on the message for grouping
 //
@@ -192,8 +196,8 @@ func (w *Writer) CommitMessage() {
 		// sentry-go v0.46.0 removed Event.Extra; attach the key-value pairs
 		// as a named context instead (sentry.Context is map[string]any).
 		logCtx := make(sentry.Context, len(w.config.extra)+len(w.values))
-		maps.Copy(logCtx, w.config.extra)
-		maps.Copy(logCtx, w.values)
+		copyContextValues(logCtx, w.config.extra)
+		copyContextValues(logCtx, w.values)
 		if len(logCtx) > 0 {
 			event.Contexts["log"] = logCtx
 		}
@@ -209,6 +213,34 @@ func (w *Writer) CommitMessage() {
 	}
 }
 
+const (
+	// reservedContextKey is the key Sentry reserves inside every context
+	// object to identify the context's type. Within our "log" context it
+	// defaults to "log" when absent; a value logged under this key would be
+	// consumed as the context type instead of being shown as data.
+	// See https://develop.sentry.dev/sdk/data-model/event-payloads/contexts/.
+	reservedContextKey = "type"
+
+	// remappedContextKey is where a logged "type" value is stored instead, so
+	// it survives as ordinary context data. The Event.Extra map removed in
+	// sentry-go v0.46.0 had no reserved keys, so this collision is unique to
+	// the context-based encoding.
+	remappedContextKey = "type_"
+)
+
+// copyContextValues copies src into dst, remapping the Sentry-reserved
+// [reservedContextKey] ("type") to [remappedContextKey] ("type_") so a golog
+// value logged under "type" is preserved as data rather than swallowed by
+// Sentry as the context type.
+func copyContextValues(dst, src map[string]any) {
+	for k, v := range src {
+		if k == reservedContextKey {
+			k = remappedContextKey
+		}
+		dst[k] = v
+	}
+}
+
 // filterFrames removes golog internal frames from stack traces to provide
 // cleaner Sentry debugging information by focusing on application code.
 func filterFrames(frames []sentry.Frame) []sentry.Frame {

logsentry/writer_test.go

@@ -108,6 +108,34 @@ func TestWriterContextValues(t *testing.T) {
 	}
 }
 
+// TestWriterReservedTypeKey verifies that a value logged under the Sentry-
+// reserved "type" key is remapped to "type_" so it survives as context data,
+// for both per-message values and config-level extra.
+func TestWriterReservedTypeKey(t *testing.T) {
+	transport := &captureTransport{}
+	hub := newTestHub(t, transport)
+
+	config := NewWriterConfig(hub, golog.NewDefaultFormat(), golog.AllLevelsActive, false,
+		map[string]any{"type": "from-extra"})
+	logger := golog.NewLogger(golog.NewConfig(&golog.DefaultLevels, golog.AllLevelsActive, config))
+
+	logger.Error("boom").Str("type", "invoice").Log()
+	hub.Flush(time.Second)
+
+	if len(transport.events) != 1 {
+		t.Fatalf("expected 1 event, got %d", len(transport.events))
+	}
+	logCtx := transport.events[0].Contexts["log"]
+
+	if _, present := logCtx["type"]; present {
+		t.Errorf(`log["type"] should be absent (reserved); got %#v`, logCtx["type"])
+	}
+	// Per-message value wins over config extra under the remapped key.
+	if got := logCtx["type_"]; got != "invoice" {
+		t.Errorf(`log["type_"] = %#v, want %q`, got, "invoice")
+	}
+}
+
 // TestWriterTimeDefaultFormat verifies time formatting falls back to
 // golog.DefaultTimeFormat when Format.TimeFormat is empty, in the time's
 // original location when Format.Location is nil.