From 2eff29d3dc8920824ec90750b2727622f3c6ed29 Mon Sep 17 00:00:00 2001
From: hyperpolymath <6759885+hyperpolymath@users.noreply.github.com>
Date: Wed, 20 May 2026 09:56:07 +0100
Subject: [PATCH] fix(mongodb-mcp): add BsonFieldType enum to Zig FFI
 (standards#155)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Closes the Class C ABI gap surfaced by the Phase 2 full-tree survey:
`MongodbMcp.SafeDatabase.BsonFieldType` (11 BSON wire-protocol field
types with explicit `bsonFieldTypeToInt` encoding 1–18 with gaps at
6, 11–15, 17 per the BSON spec) was declared in the Idris2 ABI but
absent from `mongodb_mcp_ffi.zig`. Adds the matching
`pub const BsonFieldType = enum(c_int)` with the same encoding.

Scope is ABI parity only. The wire-protocol encoder/decoder that
*uses* these tags is a separate piece of work — declaring the enum
here lets `iseriser abi-verify` structurally check the encoding
against the Idris2 source, and unblocks mongodb-mcp for the
boj-server abi-drift allowlist.

## Verified

```
$ iseriser abi-emit-manifest --idris cartridges/mongodb-mcp/abi/MongodbMcp/SafeDatabase.idr \
    --cartridge mongodb-mcp --source-path … --out /tmp/m.json
abi-emit-manifest: wrote /tmp/m.json (3 enums, 0 transitions)

$ iseriser abi-verify --manifest /tmp/m.json \
    --zig-ffi cartridges/mongodb-mcp/ffi/mongodb_mcp_ffi.zig
abi-verify: OK — cartridge `mongodb-mcp` ABI manifest agrees with `…/mongodb_mcp_ffi.zig`
exit=0
```

`zig build test` 17/17 green.

After merge, mongodb-mcp can join the abi-drift allowlist (currently
56 cartridges per boj-server#115).

Closes hyperpolymath/standards#155
Refs hyperpolymath/standards#92
Refs hyperpolymath/standards#89

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
---
 .../mongodb-mcp/ffi/mongodb_mcp_ffi.zig       | 21 +++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/cartridges/mongodb-mcp/ffi/mongodb_mcp_ffi.zig b/cartridges/mongodb-mcp/ffi/mongodb_mcp_ffi.zig
index 9fdb10ac..5755d7b0 100644
--- a/cartridges/mongodb-mcp/ffi/mongodb_mcp_ffi.zig
+++ b/cartridges/mongodb-mcp/ffi/mongodb_mcp_ffi.zig
@@ -43,6 +43,27 @@ pub const MongodbAction = enum(c_int) {
     list_databases = 15,
 };
 
+/// BSON wire-protocol field type tags. Matches Idris2
+/// `MongodbMcp.SafeDatabase.BsonFieldType` + `bsonFieldTypeToInt`.
+/// Integer codes follow the BSON spec — gaps (6, 11–15, 17) are by
+/// design (reserved / deprecated BSON codes Idris2 does not expose).
+/// Declared here so `iseriser abi-verify` can structurally check the
+/// encoding against the Idris2 source; the wire-protocol encoder will
+/// use these values when introduced.
+pub const BsonFieldType = enum(c_int) {
+    bson_double = 1,
+    bson_string = 2,
+    bson_document = 3,
+    bson_array = 4,
+    bson_binary = 5,
+    bson_object_id = 7,
+    bson_bool = 8,
+    bson_date_time = 9,
+    bson_null = 10,
+    bson_int32 = 16,
+    bson_int64 = 18,
+};
+
 /// Validate a state transition against the proven Idris2 transition graph.
 fn isValidTransition(from: ConnState, to: ConnState) bool {
     return switch (from) {