From 10716a729002d4ad1b19dd91fa3af4bd327755bc Mon Sep 17 00:00:00 2001
From: achingbrain <alex@achingbrain.net>
Date: Fri, 18 Sep 2026 10:43:48 +0300
Subject: [PATCH 1/2] fix: add warning for incorrect packed option usage

`packed` is only supported by proto2 (and proto3 but protobuf.js
ignores it), so show a warning to the user if their `.proto` file
needs updating.
---
 packages/protons/src/fields/field.ts | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/packages/protons/src/fields/field.ts b/packages/protons/src/fields/field.ts
index 1f604eb..5f4ed4a 100644
--- a/packages/protons/src/fields/field.ts
+++ b/packages/protons/src/fields/field.ts
@@ -133,6 +133,30 @@ export class Field implements MessageField {
         console.info(`[WARN] ${message}`)
       }
     }
+
+    if (parent.def.edition === 'proto2') {
+      if (def.options?.features?.repeated_field_encoding != null) {
+        const message = `field "${name}" has the features.repeated_field_encoding=${def.options.features.repeated_field_encoding} option, this is unsupported in proto2. Please use packed=${def.options?.features?.repeated_field_encoding === 'PACKED' ? true : false} instead - see https://protobuf.dev/editions/features/#repeated_field_encoding`
+
+        if (parent.flags?.strict === true) {
+          throw new ParseError(message)
+        } else {
+          // eslint-disable-next-line no-console
+          console.info(`[WARN] ${message}`)
+        }
+      }
+    } else {
+      if (def.options?.packed != null) {
+        const message = `field "${name}" has the packed=${def.options.packed} option, this is unsupported in edition="${parent.def.edition}". Please use features.repeated_field_encoding=${def.options?.packed === true ? 'PACKED' : 'EXPANDED'} instead - see https://protobuf.dev/editions/features/#repeated_field_encoding`
+
+        if (parent.flags?.strict === true) {
+          throw new ParseError(message)
+        } else {
+          // eslint-disable-next-line no-console
+          console.info(`[WARN] ${message}`)
+        }
+      }
+    }
   }
 
   getDecoderInterfaceField (parent: Parent, indent = ''): string {

From 6350c11abeda1b08fb7b2413f3ddde9c6d329444 Mon Sep 17 00:00:00 2001
From: achingbrain <alex@achingbrain.net>
Date: Fri, 18 Sep 2026 10:45:38 +0300
Subject: [PATCH 2/2] chore: linting

---
 packages/protons/src/fields/field.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/protons/src/fields/field.ts b/packages/protons/src/fields/field.ts
index 5f4ed4a..fa8dfd2 100644
--- a/packages/protons/src/fields/field.ts
+++ b/packages/protons/src/fields/field.ts
@@ -136,7 +136,7 @@ export class Field implements MessageField {
 
     if (parent.def.edition === 'proto2') {
       if (def.options?.features?.repeated_field_encoding != null) {
-        const message = `field "${name}" has the features.repeated_field_encoding=${def.options.features.repeated_field_encoding} option, this is unsupported in proto2. Please use packed=${def.options?.features?.repeated_field_encoding === 'PACKED' ? true : false} instead - see https://protobuf.dev/editions/features/#repeated_field_encoding`
+        const message = `field "${name}" has the features.repeated_field_encoding=${def.options.features.repeated_field_encoding} option, this is unsupported in proto2. Please use packed=${def.options?.features?.repeated_field_encoding === 'PACKED'} instead - see https://protobuf.dev/editions/features/#repeated_field_encoding`
 
         if (parent.flags?.strict === true) {
           throw new ParseError(message)