Release 0.35.0-alpha.1

This updates `rust-release.yml` so that the last step of creating a
release entails updating the `latest-alpha-cli` branch to point to the
tag used to create the latest release. This will facilitate building
automation to identify the most recent alpha release of Codex CLI
(though note this branch could also point to an official release, as it
is implemented today).

This introduces a new job, `update-branch`, which depends on the
`release` job. I made it separate from the `release` job because
`update-branch` needs the `contents: write` permission, so this limits
the amount of work we do with that permission.

Note I also created a branch protection rule for `latest-alpha-cli`
that:

- specifies repository admins as the only members of the bypass list
- only those with bypass permissions can create, update, or delete this
branch
- this branch requires a linear history
- note that force pushes _are_ allowed

This is the first step in fixing
https://github.com/openai/codex/issues/3098.

.github/workflows/rust-ci.yml

@@ -62,6 +62,8 @@ jobs:
           components: rustfmt
       - name: cargo fmt
         run: cargo fmt -- --config imports_granularity=Item --check
+      - name: Verify codegen for mcp-types
+        run: ./mcp-types/check_lib_rs.py
 
   cargo_shear:
     name: cargo shear

.github/workflows/rust-release.yml

@@ -219,3 +219,22 @@ jobs:
         with:
           tag: ${{ github.ref_name }}
           config: .github/dotslash-config.json
+
+  update-branch:
+    name: Update latest-alpha-cli branch
+    permissions:
+      contents: write
+    needs: release
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Update latest-alpha-cli branch
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          set -euo pipefail
+          gh api \
+            repos/${GITHUB_REPOSITORY}/git/refs/heads/latest-alpha-cli \
+            -X PATCH \
+            -f sha="${GITHUB_SHA}" \
+            -f force=true

codex-rs/Cargo.toml

@@ -22,7 +22,7 @@ members = [
 resolver = "2"
 
 [workspace.package]
-version = "0.0.0"
+version = "0.35.0-alpha.1"
 # Track the edition for all workspace crates in one place. Individual
 # crates can still override this value, but keeping it here means new
 # crates created with `cargo new -w ...` automatically inherit the 2024

codex-rs/mcp-types/check_lib_rs.py

@@ -0,0 +1,21 @@
+#!/usr/bin/env python3
+
+import subprocess
+import sys
+from pathlib import Path
+
+
+def main() -> int:
+    crate_dir = Path(__file__).resolve().parent
+    generator = crate_dir / "generate_mcp_types.py"
+
+    result = subprocess.run(
+        [sys.executable, str(generator), "--check"],
+        cwd=crate_dir,
+        check=False,
+    )
+    return result.returncode
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())

codex-rs/mcp-types/generate_mcp_types.py

@@ -5,15 +5,19 @@ import argparse
 import json
 import subprocess
 import sys
+import tempfile
 
 from dataclasses import (
     dataclass,
 )
+from difflib import unified_diff
 from pathlib import Path
+from shutil import copy2
 
 # Helper first so it is defined when other functions call it.
 from typing import Any, Literal
 
+
 SCHEMA_VERSION = "2025-06-18"
 JSONRPC_VERSION = "2.0"
 
@@ -43,16 +47,31 @@ def main() -> int:
     default_schema_file = (
         Path(__file__).resolve().parent / "schema" / SCHEMA_VERSION / "schema.json"
     )
+    default_lib_rs = Path(__file__).resolve().parent / "src/lib.rs"
     parser.add_argument(
         "schema_file",
         nargs="?",
         default=default_schema_file,
         help="schema.json file to process",
     )
+    parser.add_argument(
+        "--check",
+        action="store_true",
+        help="Regenerate lib.rs in a sandbox and ensure the checked-in file matches",
+    )
     args = parser.parse_args()
-    schema_file = args.schema_file
+    schema_file = Path(args.schema_file)
+    crate_dir = Path(__file__).resolve().parent
 
-    lib_rs = Path(__file__).resolve().parent / "src/lib.rs"
+    if args.check:
+        return run_check(schema_file, crate_dir, default_lib_rs)
+
+    generate_lib_rs(schema_file, default_lib_rs, fmt=True)
+    return 0
+
+
+def generate_lib_rs(schema_file: Path, lib_rs: Path, fmt: bool) -> None:
+    lib_rs.parent.mkdir(parents=True, exist_ok=True)
 
     global DEFINITIONS  # Allow helper functions to access the schema.
 
@@ -117,9 +136,7 @@ fn default_jsonrpc() -> String {{ JSONRPC_VERSION.to_owned() }}
 
     for req_name in CLIENT_REQUEST_TYPE_NAMES:
         defn = definitions[req_name]
-        method_const = (
-            defn.get("properties", {}).get("method", {}).get("const", req_name)
-        )
+        method_const = defn.get("properties", {}).get("method", {}).get("const", req_name)
         payload_type = f"<{req_name} as ModelContextProtocolRequest>::Params"
         try_from_impl_lines.append(f'            "{method_const}" => {{\n')
         try_from_impl_lines.append(
@@ -128,9 +145,7 @@ fn default_jsonrpc() -> String {{ JSONRPC_VERSION.to_owned() }}
         try_from_impl_lines.append(
             f"                let params: {payload_type} = serde_json::from_value(params_json)?;\n"
         )
-        try_from_impl_lines.append(
-            f"                Ok(ClientRequest::{req_name}(params))\n"
-        )
+        try_from_impl_lines.append(f"                Ok(ClientRequest::{req_name}(params))\n")
         try_from_impl_lines.append("            },\n")
 
     try_from_impl_lines.append(
@@ -144,9 +159,7 @@ fn default_jsonrpc() -> String {{ JSONRPC_VERSION.to_owned() }}
 
     # Generate TryFrom for ServerNotification
     notif_impl_lines: list[str] = []
-    notif_impl_lines.append(
-        "impl TryFrom<JSONRPCNotification> for ServerNotification {\n"
-    )
+    notif_impl_lines.append("impl TryFrom<JSONRPCNotification> for ServerNotification {\n")
     notif_impl_lines.append("    type Error = serde_json::Error;\n")
     notif_impl_lines.append(
         "    fn try_from(n: JSONRPCNotification) -> std::result::Result<Self, Self::Error> {\n"
@@ -155,9 +168,7 @@ fn default_jsonrpc() -> String {{ JSONRPC_VERSION.to_owned() }}
 
     for notif_name in SERVER_NOTIFICATION_TYPE_NAMES:
         n_def = definitions[notif_name]
-        method_const = (
-            n_def.get("properties", {}).get("method", {}).get("const", notif_name)
-        )
+        method_const = n_def.get("properties", {}).get("method", {}).get("const", notif_name)
         payload_type = f"<{notif_name} as ModelContextProtocolNotification>::Params"
         notif_impl_lines.append(f'            "{method_const}" => {{\n')
         # params may be optional
@@ -167,9 +178,7 @@ fn default_jsonrpc() -> String {{ JSONRPC_VERSION.to_owned() }}
         notif_impl_lines.append(
             f"                let params: {payload_type} = serde_json::from_value(params_json)?;\n"
         )
-        notif_impl_lines.append(
-            f"                Ok(ServerNotification::{notif_name}(params))\n"
-        )
+        notif_impl_lines.append(f"                Ok(ServerNotification::{notif_name}(params))\n")
         notif_impl_lines.append("            },\n")
 
     notif_impl_lines.append(
@@ -185,13 +194,70 @@ fn default_jsonrpc() -> String {{ JSONRPC_VERSION.to_owned() }}
         for chunk in out:
             f.write(chunk)
 
-    subprocess.check_call(
-        ["cargo", "fmt", "--", "--config", "imports_granularity=Item"],
-        cwd=lib_rs.parent.parent,
-        stderr=subprocess.DEVNULL,
-    )
+    if fmt:
+        subprocess.check_call(
+            ["cargo", "fmt", "--", "--config", "imports_granularity=Item"],
+            cwd=lib_rs.parent.parent,
+            stderr=subprocess.DEVNULL,
+        )
 
-    return 0
+
+def run_check(schema_file: Path, crate_dir: Path, checked_in_lib: Path) -> int:
+    config_path = crate_dir.parent / "rustfmt.toml"
+    eprint(f"Running --check with schema {schema_file}")
+
+    with tempfile.TemporaryDirectory() as tmp_dir:
+        tmp_path = Path(tmp_dir)
+        eprint(f"Created temporary workspace at {tmp_path}")
+        manifest_path = tmp_path / "Cargo.toml"
+        eprint(f"Copying Cargo.toml into {manifest_path}")
+        copy2(crate_dir / "Cargo.toml", manifest_path)
+        manifest_text = manifest_path.read_text(encoding="utf-8")
+        manifest_text = manifest_text.replace(
+            "version = { workspace = true }",
+            'version = "0.0.0"',
+        )
+        manifest_text = manifest_text.replace("\n[lints]\nworkspace = true\n", "\n")
+        manifest_path.write_text(manifest_text, encoding="utf-8")
+        src_dir = tmp_path / "src"
+        src_dir.mkdir(parents=True, exist_ok=True)
+        eprint(f"Generating lib.rs into {src_dir}")
+        generated_lib = src_dir / "lib.rs"
+
+        generate_lib_rs(schema_file, generated_lib, fmt=False)
+
+        eprint("Formatting generated lib.rs with rustfmt")
+        subprocess.check_call(
+            [
+                "rustfmt",
+                "--config-path",
+                str(config_path),
+                str(generated_lib),
+            ],
+            cwd=tmp_path,
+            stderr=subprocess.DEVNULL,
+        )
+
+        eprint("Comparing generated lib.rs with checked-in version")
+        checked_in_contents = checked_in_lib.read_text(encoding="utf-8")
+        generated_contents = generated_lib.read_text(encoding="utf-8")
+
+        if checked_in_contents == generated_contents:
+            eprint("lib.rs matches checked-in version")
+            return 0
+
+        diff = unified_diff(
+            checked_in_contents.splitlines(keepends=True),
+            generated_contents.splitlines(keepends=True),
+            fromfile=str(checked_in_lib),
+            tofile=str(generated_lib),
+        )
+        diff_text = "".join(diff)
+        eprint("Generated lib.rs does not match the checked-in version. Diff:")
+        if diff_text:
+            eprint(diff_text, end="")
+        eprint("Re-run generate_mcp_types.py without --check to update src/lib.rs.")
+        return 1
 
 
 def add_definition(name: str, definition: dict[str, Any], out: list[str]) -> None:
@@ -421,15 +487,11 @@ def define_untagged_enum(name: str, type_list: list[str], out: list[str]) -> Non
             case "integer":
                 out.append("    Integer(i64),\n")
             case _:
-                raise ValueError(
-                    f"Unknown type in untagged enum: {simple_type} in {name}"
-                )
+                raise ValueError(f"Unknown type in untagged enum: {simple_type} in {name}")
     out.append("}\n\n")
 
 
-def define_any_of(
-    name: str, list_of_refs: list[Any], description: str | None = None
-) -> list[str]:
+def define_any_of(name: str, list_of_refs: list[Any], description: str | None = None) -> list[str]:
     """Generate a Rust enum for a JSON-Schema `anyOf` union.
 
     For most types we simply map each `$ref` inside the `anyOf` list to a
@@ -494,9 +556,7 @@ def define_any_of(
             if name == "ClientRequest":
                 payload_type = f"<{ref_name} as ModelContextProtocolRequest>::Params"
             else:
-                payload_type = (
-                    f"<{ref_name} as ModelContextProtocolNotification>::Params"
-                )
+                payload_type = f"<{ref_name} as ModelContextProtocolNotification>::Params"
 
             # Determine the wire value for `method` so we can annotate the
             # variant appropriately. If for some reason the schema does not
@@ -504,9 +564,7 @@ def define_any_of(
             # least compile (although deserialization will likely fail).
             request_def = DEFINITIONS.get(ref_name, {})
             method_const = (
-                request_def.get("properties", {})
-                .get("method", {})
-                .get("const", ref_name)
+                request_def.get("properties", {}).get("method", {}).get("const", ref_name)
             )
 
             out.append(f'    #[serde(rename = "{method_const}")]\n')
@@ -556,7 +614,7 @@ def map_type(
     if type_prop == "string":
         if const_prop := typedef.get("const", None):
             assert isinstance(const_prop, str)
-            return f'&\'static str = "{const_prop    }"'
+            return f'&\'static str = "{const_prop}"'
         else:
             return "String"
     elif type_prop == "integer":
@@ -632,7 +690,7 @@ def rust_prop_name(name: str, is_optional: bool) -> RustProp:
         serde_annotations.append('skip_serializing_if = "Option::is_none"')
 
     if serde_annotations:
-        serde_str = f'#[serde({", ".join(serde_annotations)})]'
+        serde_str = f"#[serde({', '.join(serde_annotations)})]"
     else:
         serde_str = None
     return RustProp(prop_name, serde_str)
@@ -640,9 +698,7 @@ def rust_prop_name(name: str, is_optional: bool) -> RustProp:
 
 def to_snake_case(name: str) -> str:
     """Convert a camelCase or PascalCase name to snake_case."""
-    snake_case = name[0].lower() + "".join(
-        "_" + c.lower() if c.isupper() else c for c in name[1:]
-    )
+    snake_case = name[0].lower() + "".join("_" + c.lower() if c.isupper() else c for c in name[1:])
     if snake_case != name:
         return snake_case
     else:
@@ -678,5 +734,9 @@ def emit_doc_comment(text: str | None, out: list[str]) -> None:
         out.append(f"/// {line.rstrip()}\n")
 
 
+def eprint(*args: Any, **kwargs: Any) -> None:
+    print(*args, file=sys.stderr, **kwargs)
+
+
 if __name__ == "__main__":
     sys.exit(main())