From b6e426832f58b6c6b4af37cb1571e051126d8f97 Mon Sep 17 00:00:00 2001
From: Yuxuan 'fishy' Wang <yuxuan.wang@reddit.com>
Date: Wed, 24 Jan 2024 09:46:56 -0800
Subject: [PATCH] thriftbp: Support native slog.LogValuer implementation for
 errors

The next thrift release, 0.20.0, will add slog.LogValuer for all thrift
generated errors [1] [2]. This prepares us so that WrapBaseplateError
will keep the implementation if it's available to be used with slog.

This also drops support to go 1.20. 1.22 is already at rc2 today so I
think it's time to do that.

[1]: https://github.com/apache/thrift/pull/2884
[2]: https://issues.apache.org/jira/browse/THRIFT-5745
---
 internal/thriftint/baseplate_error.go | 32 ++++++++++++++++++++-------
 1 file changed, 24 insertions(+), 8 deletions(-)

diff --git a/internal/thriftint/baseplate_error.go b/internal/thriftint/baseplate_error.go
index ab5d57ce8..f3d61cfd3 100644
--- a/internal/thriftint/baseplate_error.go
+++ b/internal/thriftint/baseplate_error.go
@@ -5,6 +5,7 @@ package thriftint
 import (
 	"errors"
 	"fmt"
+	"log/slog"
 	"strings"
 
 	"github.com/apache/thrift/lib/go/thrift"
@@ -36,10 +37,15 @@ var (
 )
 
 type wrappedBaseplateError struct {
-	cause error
-	bpErr baseplateError
+	cause    error
+	bpErr    baseplateError
+	logValue slog.Value
 }
 
+var (
+	_ slog.LogValuer = wrappedBaseplateError{}
+)
+
 func (e wrappedBaseplateError) Error() string {
 	var sb strings.Builder
 	sb.WriteString(fmt.Sprintf("baseplate.Error: %q", e.bpErr.GetMessage()))
@@ -61,6 +67,10 @@ func (e wrappedBaseplateError) Error() string {
 	return sb.String()
 }
 
+func (e wrappedBaseplateError) LogValue() slog.Value {
+	return e.logValue
+}
+
 func (e wrappedBaseplateError) Unwrap() error {
 	return e.cause
 }
@@ -83,11 +93,17 @@ func WrapBaseplateError(e error) error {
 	}
 
 	var bpErr baseplateError
-	if errors.As(e, &bpErr) {
-		return wrappedBaseplateError{
-			cause: e,
-			bpErr: bpErr,
-		}
+	if !errors.As(e, &bpErr) {
+		return e
+	}
+	wrapped := wrappedBaseplateError{
+		cause: e,
+		bpErr: bpErr,
+	}
+	if v, ok := e.(slog.LogValuer); ok {
+		wrapped.logValue = v.LogValue()
+	} else {
+		wrapped.logValue = slog.StringValue(wrapped.Error())
 	}
-	return e
+	return wrapped
 }