only pass true original_rcpt_to

docs/man/maddy-imap.5.scd

@@ -96,9 +96,8 @@ command executable_name args... { }
 
 Same as check.command, following placeholders are supported for command
 arguments: {source_ip}, {source_host}, {source_rdns}, {msg_id}, {auth_user},
-{sender}, {rcpt_to}, {original_rcpts}, {original_rcpt_to}, {address}. Note:
-placeholders in command name are not processed to avoid possible command
-injection attacks.
+{sender}, {rcpt_to}, {original_rcpt_to}, {address}. Note: placeholders in command
+name are not processed to avoid possible command injection attacks.
 
 Additionally, for imap.filter.command, {account_name} placeholder is replaced
 with effective IMAP account name.

internal/imap_filter/command/command.go

@@ -28,7 +28,6 @@ import (
 	"os"
 	"os/exec"
 	"regexp"
-	"strings"
 
 	"github.com/emersion/go-message/textproto"
 	"github.com/foxcpp/maddy/framework/buffer"
@@ -139,14 +138,12 @@ func (c *Check) expandCommand(msgMeta *module.MsgMetadata, accountName string, r
 				return msgMeta.OriginalFrom
 			case "{rcpt_to}":
 				return rcptTo
-			case "{original_rcpts}":
-				rcpts := []string{}
-				for _, value := range msgMeta.OriginalRcpts {
-					rcpts = append(rcpts, value)
-				}
-				return strings.Join(rcpts, "\n")
 			case "{original_rcpt_to}":
-				return msgMeta.OriginalRcpts[rcptTo]
+				oldestOriginalRcpt := rcptTo
+				for originalRcpt, ok := rcptTo, true; ok; originalRcpt, ok = msgMeta.OriginalRcpts[originalRcpt] {
+					oldestOriginalRcpt = originalRcpt
+				}
+				return oldestOriginalRcpt
 			case "{account_name}":
 				return accountName
 			}

internal/msgpipeline/msgpipeline.go

@@ -338,8 +338,9 @@ func (dd *msgpipelineDelivery) AddRcpt(ctx context.Context, to string) error {
 		})
 	}
 
-	//Always setting so it can be retrieved by imap_filter
-	dd.msgMeta.OriginalRcpts[to] = originalTo
+	if originalTo != to {
+		dd.msgMeta.OriginalRcpts[to] = originalTo
+	}
 
 	for _, tgt := range rcptBlock.targets {
 		// Do not wrap errors coming from nested pipeline target delivery since