From 093c7e84e85f5c4f36950c42b24892b35e3deaff Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Sat, 6 Jun 2026 19:38:12 +0000
Subject: [PATCH] Fix pb_to_json to properly escape strings.

This modifies `pb_to_json_inner` in `src/json.c` to iterate through strings
and properly escape double quotes, backslashes, and control characters like
newlines and tabs to avoid creating invalid JSON. Tests were added.

Co-authored-by: bkvaluemeal <3835053+bkvaluemeal@users.noreply.github.com>
---
 expected/pgproto_test.out |  6 ++++++
 sql/pgproto_test.sql      |  3 +++
 src/json.c                | 20 +++++++++++++++++++-
 3 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/expected/pgproto_test.out b/expected/pgproto_test.out
index b23b469..f5dbe88 100644
--- a/expected/pgproto_test.out
+++ b/expected/pgproto_test.out
@@ -569,3 +569,9 @@ ERROR:  Field nonexistent not found in message CoverageMsg
 -- 35. Test pb_insert error: Message not found
 SELECT pb_insert('\x'::protobuf, ARRAY['NonExistentMessage', 'f', '0'], '1.23');
 ERROR:  Message not found in schema registry: NonExistentMessage
+-- 36. Test pb_to_json escaping
+SELECT pb_to_json(pb_insert('\x'::protobuf, ARRAY['CoverageMsg', 'str_arr', '0'], E'hello "world"\\\n\t\b\f\r'), 'CoverageMsg');
+                 pb_to_json
+---------------------------------------------
+ {"str_arr":["hello \"world\"\\\n\t\b\f\r"]}
+(1 row)
diff --git a/sql/pgproto_test.sql b/sql/pgproto_test.sql
index 918d661..9ffdff2 100644
--- a/sql/pgproto_test.sql
+++ b/sql/pgproto_test.sql
@@ -342,3 +342,6 @@ SELECT pb_insert('\x'::protobuf, ARRAY['NonExistentMessage', 'f', '0'], '1.23');
 
 
 
+
+-- 36. Test pb_to_json escaping
+SELECT pb_to_json(pb_insert('\x'::protobuf, ARRAY['CoverageMsg', 'str_arr', '0'], E'hello "world"\\\n\t\b\f\r'), 'CoverageMsg');
diff --git a/src/json.c b/src/json.c
index 3b903e3..f7ae20c 100644
--- a/src/json.c
+++ b/src/json.c
@@ -44,7 +44,25 @@ pb_to_json_inner(const char *ptr, const char *end, const char *msg_name, StringI
                     pb_to_json_inner(ptr, ptr + len, lookup.type_name, buf);
                 } else {
                     appendStringInfoChar(buf, '"');
-                    appendBinaryStringInfo(buf, ptr, (int)len);
+                    for (int i = 0; i < (int)len; i++) {
+                        char c = ptr[i];
+                        switch (c) {
+                            case '"': appendStringInfoString(buf, "\\\""); break;
+                            case '\\': appendStringInfoString(buf, "\\\\"); break;
+                            case '\b': appendStringInfoString(buf, "\\b"); break;
+                            case '\f': appendStringInfoString(buf, "\\f"); break;
+                            case '\n': appendStringInfoString(buf, "\\n"); break;
+                            case '\r': appendStringInfoString(buf, "\\r"); break;
+                            case '\t': appendStringInfoString(buf, "\\t"); break;
+                            default:
+                                if ((unsigned char)c < 0x20) {
+                                    appendStringInfo(buf, "\\u%04x", (unsigned char)c);
+                                } else {
+                                    appendStringInfoChar(buf, c);
+                                }
+                                break;
+                        }
+                    }
                     appendStringInfoChar(buf, '"');
                 }
                 ptr += len;