feat(zapencoder): improve ctx field detection

Author: ernado

internal/zapencoder/README.md

@@ -3,4 +3,4 @@
 This package is partially vendored from `zapcore`
 Probably we can use `jx` here in the future.
 
-Changed code is located in `json_encoder_patch.go` file.
+Changed code is located in `patch.go` file.

internal/zapencoder/_golden/logs.jsonl

@@ -1,2 +1,2 @@
-{"level":"info","ts":"2024-01-02T15:04:05Z","caller":"caller.go","msg":"With context"}
-{"level":"info","ts":"2024-01-02T15:04:05Z","caller":"caller.go","msg":"With span","trace_id":"4bf92f3577b34da6a3ce929d0e0e4736","span_id":"00f067aa0ba902b7"}
+{"level":"info","ts":"2024-01-02T15:04:05Z","msg":"With context"}
+{"level":"info","ts":"2024-01-02T15:04:05Z","msg":"With span","trace_id":"4bf92f3577b34da6a3ce929d0e0e4736","span_id":"00f067aa0ba902b7"}

internal/zapencoder/json_encoder_patch.go renamed to internal/zapencoder/patch.go

@@ -23,8 +23,8 @@ const (
 
 func addFields(enc zapcore.ObjectEncoder, fields []zapcore.Field) {
 	for _, f := range fields {
-		if f.Interface != nil && f.Type == zapcore.StringerType {
-			// Test for ctx.
+		if f.Interface != nil && f.Type == zapcore.StringerType && f.Key == "ctx" {
+			// Test for context.Context.
 			ctx, ok := f.Interface.(context.Context)
 			if ok {
 				spanCtx := trace.SpanContextFromContext(ctx)
@@ -37,6 +37,7 @@ func addFields(enc zapcore.ObjectEncoder, fields []zapcore.Field) {
 					}
 				}
 
+				// Do not print ctx field.
 				continue
 			}
 		}