postgres: send a string parameter bound to json/jsonb verbatim

[robobun]

Fixes #28819

Problem

• A string bound to a json or jsonb parameter is serialized twice. JSON.stringify({hello: "world"}) is stored as a JSON string scalar: json_typeof reports string, and json_to_recordset($1::json) fails with cannot call json_to_recordset on a scalar. drizzle-orm/bun-sql and pg-boss stringify before they bind, so both break.
• The cause is write_bind (src/sql_jsc/postgres/PostgresRequest.rs:173): the json/jsonb arm calls json_stringify_fast on every value, strings included.

Fix

• A string bound to json/jsonb now takes the generic text arm, which writes its UTF-8 bytes verbatim. Objects and arrays keep json_stringify_fast.
• node-postgres does the same for a string. postgres.js does not: it stringifies the string again, as Bun did.
• Behavior change: a bare string is now JSON text. ${"hello"}::json stored the JSON string "hello" and now fails with 22P02 invalid input syntax for type json. ${"42"}::jsonb stored a string and now stores the number 42, with no error. To store a JSON string, pass JSON.stringify(str). docs/runtime/sql.mdx states the rule.
• Verified: test/js/sql/postgres-json-string-param.test.ts (10 tests, 8 fail without the fix). Also ran postgres-bytea-bind.test.ts, sql-prepare-false.test.ts, and the 40 json tests of sql.test.ts (results in Notes). Self-reviewed: 3 concerns raised, 3 addressed.

Background

• After Parse, the server's ParameterDescription message reports the type OID of each parameter. For OID 114 (json) or 3802 (jsonb) the driver formats the value itself.
• json and jsonb use the text wire format, so the Bind payload is the JSON text. That does not change.
• MySQL is not affected. That driver selects MYSQL_TYPE_JSON only for an object.

Notes

Repro from the issue:

const payload = JSON.stringify([{ id: 1, name: "a" }]);
const [row] = await sql.unsafe("SELECT json_typeof($1::json) AS kind", [payload]);
// before: { kind: "string" }   after: { kind: "array" }

Other drivers, measured on the same server with SELECT json_typeof($1::json):

input	pg 8.11.1	postgres 3.3.5	Bun before	Bun after
JSON.stringify({hello:"world"})	object	string	string	object
JSON.stringify([1,2,3])	array	string	string	array
JSON.stringify(42)	number	string	string	number
JSON.stringify("hello")	string	string	string	string
plain "hello"	ERROR 22P02	string	string	ERROR 22P02
plain "42"	number	string	string	number
raw object	object	object	object	object
raw array [1,2,3]	ERROR 22P02	array	array	array

• The last row is a difference from node-postgres that stays. node-postgres sends a JS array as a Postgres array literal. Bun serializes it as JSON, before and after this change.
• postgres.js lets a caller replace the serializers for OID 114 and 3802, and drizzle does that. Bun.SQL has no such hook, so drizzle-orm/bun-sql cannot work around the double encoding.
• A heuristic (send verbatim only if the string parses as JSON) is not used. The result would depend on the data: "42", "null", and "true" would change type with no error.
• Entry points covered by tests: tagged template with a cast, insert into json and jsonb columns with no cast, sql.unsafe(query, [param]), the sql({...}) insert helper, and prepare: false.
• The non-ASCII tests cover both transcode arms of to_utf8 (Latin-1 and UTF-16 source strings).
• No existing test in test/js/sql/ binds a string to a json or jsonb parameter. The existing binds pass objects or arrays.

Test runs on a debug build against a local PostgreSQL 17:

• postgres-json-string-param.test.ts: 10 pass. On 1.4.3-canary.1+09bb54630 without the fix: 8 fail. The 2 that pass both ways are controls (an object is still stringified, and prepare: false was already correct).
• postgres-bytea-bind.test.ts: 6 pass. sql-prepare-false.test.ts: 8 pass.
• sql.test.ts -t json: 38 pass, 2 fail. The 2 failures (jsonb[] - unicode escape sequences and jsonb[] - mixed unicode and escape sequences) fail the same way without the fix. They bind no parameter. My local database uses the SQL_ASCII encoding, which rejects \u escapes above ASCII. The rest of the Postgres block in sql.test.ts needs docker, so I did not run it locally.
• postgres-json-bind-leak.fixture.ts, run directly: RSS delta 12 MiB (bound 80). It binds an object, so it stays on the json_stringify_fast path.

History:

• sql: don't double-encode pre-stringified JSON parameters #28821 had the same fix for the Zig sources. It was closed unmerged when the Zig files were removed.
• Bun.SQL: a string parameter bound to a ::json cast arrives as a JSON string scalar #40942 is a duplicate report of bug(SQL): bun-sql double encodes all values inserted into json and jsonb columns with Postgres 18, their resulting type is always string #28819.
• While writing the error-case test I hit an unrelated hang: await expect(sqlQuery).rejects.toThrow(...) never settles, because the lazy Query only dispatches inside its overridden then(). Filed as bun:test: expect(thenable).rejects hangs when the thenable starts work in its overridden then() #40949. The test calls .execute() first, the same workaround as sql-mysql-bigint-out-of-range.test.ts.

---

[human-review] gate passed · iteration 3 · 3 files touched

fails on main (without fix)

ASAN without fix: 8 FAILED
$ BUN_DEBUG_QUIET_LOGS=1 bun scripts/build.ts --profile=debug --quiet test "--reporter=junit" "--reporter-outfile=/tmp/pr_gate.xml" test/js/sql/postgres-json-string-param.test.ts
bun test v1.4.3 (09bb54630)

test/js/sql/postgres-json-string-param.test.ts:
Container ready via docker-compose: postgres_plain at 127.0.0.1:5432
19 |   test("string parameter bound to ::json is sent as the JSON text itself", async () => {
20 |     await container.ready;
21 |     await using sql = new SQL(options());
22 |     const payload = JSON.stringify([{ id: 1, name: "a" }]);
23 |     const [row] = await sql`select json_typeof(${payload}::json) as kind, ${payload}::json as value`;
24 |     expect(row).toEqual({ kind: "array", value: [{ id: 1, name: "a" }] });
                     ^
error: expect(received).toEqual(expected)

  {
-   "kind": "array",
-   "value": [
-     {
-       "id": 1,
-       "name": "a",
-     },
-   ],
+   "kind": "string",
+   "value": "[{"id":1,"name":"a"}]",
  }

- Expected  - 7
+ Received  + 2

      at <anonymous> (/workspace/bun/test/js/sql/postgres-json-string-param.test.ts:24:17)
(fail) postgres json string parameters > string parameter bound to ::json is 
... (truncated)

release without fix: 8 FAILED
bun test v1.4.3-canary.1 (09bb54630)

test/js/sql/postgres-json-string-param.test.ts:
Container ready via docker-compose: postgres_plain at 127.0.0.1:5432
19 |   test("string parameter bound to ::json is sent as the JSON text itself", async () => {
20 |     await container.ready;
21 |     await using sql = new SQL(options());
22 |     const payload = JSON.stringify([{ id: 1, name: "a" }]);
23 |     const [row] = await sql`select json_typeof(${payload}::json) as kind, ${payload}::json as value`;
24 |     expect(row).toEqual({ kind: "array", value: [{ id: 1, name: "a" }] });
                     ^
error: expect(received).toEqual(expected)

  {
-   "kind": "array",
-   "value": [
-     {
-       "id": 1,
-       "name": "a",
-     },
-   ],
+   "kind": "string",
+   "value": "[{"id":1,"name":"a"}]",
  }

- Expected  - 7
+ Received  + 2

      at <anonymous> (/workspace/bun/test/js/sql/postgres-json-string-param.test.ts:24:17)
(fail) postgres json string parameters > string parameter bound to ::json is sent as the JSON text itself [7.79ms]
27 |   test("string parameter bound to ::jsonb is sent as the JSON text itself", async () => {
28 |     await container.ready;
29 | 
... (truncated)

passes on PR (with fix)

ASAN with fix: all passed
$ BUN_DEBUG_QUIET_LOGS=1 bun scripts/build.ts --profile=debug --quiet test "--reporter=junit" "--reporter-outfile=/tmp/pr_gate.xml" test/js/sql/postgres-json-string-param.test.ts
bun test v1.4.3 (09bb54630)

test/js/sql/postgres-json-string-param.test.ts:
Container ready via docker-compose: postgres_plain at 127.0.0.1:5432
(pass) postgres json string parameters > string parameter bound to ::json is sent as the JSON text itself [252.16ms]
(pass) postgres json string parameters > string parameter bound to ::jsonb is sent as the JSON text itself [28.72ms]
(pass) postgres json string parameters > non-ASCII JSON text (Latin-1) round-trips through the verbatim path [23.22ms]
(pass) postgres json string parameters > non-ASCII JSON text (UTF-16) round-trips through the verbatim path [12.43ms]
(pass) postgres json string parameters > json_to_recordset accepts a stringified array parameter [24.14ms]
(pass) postgres json string parameters > stringified values inserted into json and jsonb columns keep their JSON type [59.26ms]
(pass) postgres json string parameters > sql() insert helper sends stringified values verbatim [46.79ms]
(pass) postgres json string parameters > object 
... (truncated)

release with fix: all passed
$ bun scripts/build.ts --profile=release
[configured] bun-profile → bun (stripped) in 657ms (unchanged)
ninja: Entering directory `/workspace/bun/build/release'
[0/6] cargo bun_runtime → libbun_runtime.a
�[1m�[92m   Compiling�[0m bun_sql_jsc v0.0.0 (/workspace/bun/src/sql_jsc)
�[1m�[92m   Compiling�[0m bun_runtime v0.0.0 (/workspace/bun/src/runtime)
�[1m�[92m    Finished�[0m `release` profile [optimized + debuginfo] target(s) in 1m 32s
[2/6] link bun-profile
rust-lld: warning: Linking two modules of different target triples: 'obj/unified/UnifiedSource-src_jsc_bindings-0.cpp.o' is 'x86_64-pc-linux-gnu' whereas '../../../../root/.bun/build-cache/webkit-65513e295c73416a-lto/lib/libJavaScriptCore.a(UnifiedSource-inspector-2.cpp.o at 97577272)' is 'x86_64-unknown-linux-gnu'


rust-lld: warning: Linking two modules of different target triples: 'obj/unified/UnifiedSource-src_jsc_bindings-1.cpp.o' is 'x86_64-pc-linux-gnu' whereas '../../../../root/.bun/build-cache/webkit-65513e295c73416a-lto/lib/libJavaScriptCore.a(UnifiedSource-inspector-2.cpp.o at 97577272)' is 'x86_64-unknown-linux-gnu'


rust-lld: warning: Linking two modules of different target triples: 'obj/vendor
... (truncated)

diff hotspot

docs/runtime/sql.mdx                           |  17 ++++
 src/sql_jsc/postgres/PostgresRequest.rs        |   9 +-
 test/js/sql/postgres-json-string-param.test.ts | 115 +++++++++++++++++++++++++
 3 files changed, 139 insertions(+), 2 deletions(-)

gate history · 2 passed · 0 rejected · iteration 3

evidence per changed file

file                                            reads  edits  tests
docs/runtime/sql.mdx                                0      0     18
src/sql_jsc/postgres/PostgresRequest.rs             2      4     18
test/js/sql/postgres-json-string-param.test.ts      3      9     18

root cause · written by the author bot

When a parameter was typed json or jsonb, the Postgres bind path passed every value through JSON serialization, so a string that already contained JSON text was encoded a second time and reached the server as a JSON string scalar rather than the document it spelled out. The fix checks whether the bound value is a JavaScript string and, if so, sends it as text unchanged while still serializing objects and arrays, so the server parses the string as JSON and $1::json yields the array or object the caller intended. This matches the behavior of node-postgres and lets libraries that serialize t…

[robobun]

^{Updated 11:01 AM PT - Sep 15th, 2026}

✅ @robobun, your commit aaffd7435c282edec04129468e5908bb474fde28 passed in Build #116013! 🎉

---

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Walkthrough

Changes

PostgreSQL JSON and JSONB string parameters now bypass JSON serialization and reach PostgreSQL as verbatim text. Non-string values retain serialization. Tests and documentation cover valid, invalid, prepared, unprepared, and non-ASCII JSON values.

PostgreSQL JSON binding

Layer / File(s)	Summary
JSON parameter conversion src/sql_jsc/postgres/PostgresRequest.rs, docs/runtime/sql.mdx	String values for json and jsonb use text handling. Other values continue through JSON serialization. The documentation describes these rules and PostgreSQL validation errors.
PostgreSQL JSON integration validation test/js/sql/postgres-json-string-param.test.ts	Integration tests cover JSON and JSONB parameters, inserts, recordsets, non-ASCII values, prepared and unprepared queries, object serialization, and invalid JSON strings.

Suggested reviewers: alii

Priority: ⬇️ Low

Merge Risk: 🔵 Low · up to 8dc6f

Private git dependency installation and resolving newly pushed revisions can still fail in the documented cases. These issues warrant owner awareness before merging, while the PostgreSQL change itself has a small documentation correction.

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title clearly and concisely describes the main change: PostgreSQL string parameters for json/jsonb are sent verbatim.
Description check	✅ Passed	The description explains the problem, fix, behavior change, scope, and verification results in detail. It does not use the template headings exactly, but it provides the required information under equ…

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[claude]

LGTM — small, targeted fix that mirrors the existing text-format arm.

What was reviewed:

• The new value.is_string() branch in write_bind's json/jsonb arm reuses the exact BunString::from_js + Tag::Dead OOM pattern from the generic text arm at line 230, so error handling and lifetime are identical.
• Confirmed json/jsonb are text-format tags (not caught by the is_binary_format_supported() string escape hatch above), so this arm is the only place a string bound to json could land.
• Tests cover the variant matrix: json + jsonb, prepared + prepare: false, object params still stringified, and the negative contract (non-JSON string surfaces the server's parse error).

Extended reasoning...

Overview

This PR changes one match arm in src/sql_jsc/postgres/PostgresRequest.rs (write_bind, Tag::json | Tag::jsonb) so that a JS string parameter is sent to Postgres verbatim rather than being run through json_stringify_fast, which was double-encoding it into a JSON string scalar. Non-string values keep the existing stringify path. A new test file test/js/sql/postgres-json-string-param.test.ts uses the container harness to verify the fix across json/jsonb, json_to_recordset, prepare: false, and the error path, plus a regression guard that plain objects are still stringified.

Security risks

None. The change only affects how a client-supplied parameter is serialized into a Bind message's parameter payload; it's still a bound parameter (not interpolated into SQL text), so there's no injection surface. The bytes are written through the same length-prefixed writer as before. Invalid JSON now produces a server-side parse error, which is the same behavior node-postgres and postgres.js exhibit.

Level of scrutiny

Low-to-medium. The Rust delta is ~10 lines and is a byte-for-byte copy of the sibling _ => arm's string handling (same BunString::from_js, same Tag::Dead → OutOfMemory mapping, same to_utf8() → writer.write(slice.slice())). The is_string() guard is checked before any coercion, so no user getters or Proxy traps run between the check and the conversion. Exception propagation via .map_err(js_error_to_postgres)? matches every other arm in the function.

Other factors

The new test file follows the well-established test/js/sql/postgres-*.test.ts per-issue pattern in that directory (dozens of siblings), uses describeWithContainer and await using sql, awaits container.ready, and asserts whole result objects with .toEqual. No CODEOWNERS entry covers the changed paths. The bug hunt exited on dry_streak with no findings. This is a focused compatibility fix with clear intent and good coverage.

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Inline comments:
In `@test/js/sql/postgres-json-string-param.test.ts`:
- Line 40: Update the JSON parameter test around the doc payload to use separate
documents: keep the existing UTF-16 case with emoji/CJK characters, add a
Latin-1-only document, and assert each document independently so both transcode
paths are covered.

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Inline comments:
In `@src/install/git_runner.rs`:
- Line 796: Update the URL fallback condition in the git runner so `not_found`
only short-circuits when no additional URL forms remain; allow the SSH fallback
to run for private repositories after unauthenticated HTTPS reports “Repository
not found.” Preserve the existing behavior for the final URL form and the
`this.urls` exhaustion check.
- Around line 470-476: Update the git fetch invocation in the Fetch step to
refresh the bare cache’s branch refs by using mirror semantics or an explicit
refspec; preserve the existing cache path and quiet fetch behavior while
ensuring newly pushed branches are available to later git log operations.

In `@test/js/sql/postgres-json-string-param.test.ts`:
- Line 42: Replace the manual loop over latin1Doc and utf16Doc with a
describe.each()-based parameterized test structure so each transcoding case
executes and reports independently, preserving the existing assertions and test
behavior.

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[claude]

Nothing blocking. The comments below are optional suggestions. There is no need to push a fix for them before merging.

[claude]

LGTM — the stray src/install/git_runner.rs is gone and the non-ASCII test now splits Latin-1 and UTF-16 into separate test.each arms, so both earlier concerns are addressed.

What was reviewed:

• write_bind: the widened guard only redirects string values; objects/arrays still reach the json_stringify_fast arm, and the _ => fallback writes the string via to_utf8() verbatim.
• Confirmed json/jsonb are not in is_binary_format_supported(), so the format-codes loop earlier in write_bind still emits text (0) for them — wire format unchanged.
• Test file: await using cleanup, container-provided host/port, .toEqual on nested results, error case uses .execute() per the noted lazy-Query hang.

Extended reasoning...

Overview

The PR is now back to two files: a 5-line conditional widening in src/sql_jsc/postgres/PostgresRequest.rs::write_bind and a new 84-line test file. The unrelated 977-line src/install/git_runner.rs that I flagged in the previous run has been removed (verified absent on disk and absent from git diff --stat). The non-ASCII round-trip test was reworked into a test.each with two separate payloads — one Latin-1-only ("café") and one UTF-16-forcing (emoji + CJK) — addressing the earlier nit that a single mixed payload only exercised the UTF-16 transcode arm.

Security risks

None. The change affects how a client-supplied JS string is serialized into a Postgres Bind message parameter. It does not touch SQL text construction, so there is no injection surface change; the string is length-prefixed on the wire either way. The behavioral shift (Postgres now parses the string as JSON server-side rather than receiving a JSON string scalar) matches node-postgres and postgres.js, and invalid JSON now surfaces as the server's own invalid input syntax for type json error — covered by a test.

Level of scrutiny

Low-to-moderate. The Rust change is a single boolean widening on an existing escape hatch, and I traced the resulting types::Tag::text through the match: it falls into the _ => arm which does BunString::from_js → to_utf8() → length-prefixed write, exactly the verbatim path intended. Non-string values keep effective_tag = tag and hit the unchanged json | jsonb arm. The format-codes loop above the match keys on tag.is_binary_format_supported() (not effective_tag), and json/jsonb are text-format tags, so the wire format code stays 0.

Other factors

Seven tests cover json vs jsonb, both string encodings, json_to_recordset via sql.unsafe, the object-still-stringified negative, prepare: false, and the server-side error path. The prepare: false test I previously noted as not exercising the changed guard was an optional nit and I won't repeat it. No outstanding CHANGES_REQUESTED reviews; the coderabbitai threads on git_runner.rs are moot now that the file is removed. Exit reason was dry_streak.

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Inline comments:
In `@docs/runtime/sql.mdx`:
- Line 316: Update the JSON binding guidance near the existing JSON.stringify
note to explicitly document that storing JSON null requires passing
JSON.stringify(null), since a direct JavaScript null becomes SQL NULL before
JSON/jsonb serialization.

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[claude]

Nothing blocking. The comments below are optional suggestions. There is no need to push a fix for them before merging.

[claude]

Code review found no issues

No high-confidence issues detected in this change.