emacs.pkgs.tsc: Add update script

pkgs/applications/editors/emacs/elisp-packages/tsc/default.nix

@@ -6,6 +6,12 @@
 , writeText
 , clang
 , llvmPackages
+
+, runtimeShell
+, writeScript
+, python3
+, nix-prefetch-github
+, nix
 }:
 
 let
@@ -63,6 +69,21 @@ in symlinkJoin {
   name = "tsc-${version}";
   paths = [ tsc tsc-dyn ];
 
+  passthru = {
+    updateScript = let
+      pythonEnv = python3.withPackages(ps: [ ps.requests ]);
+    in writeScript "tsc-update" ''
+      #!${runtimeShell}
+      set -euo pipefail
+      export PATH=${lib.makeBinPath [
+        nix-prefetch-github
+        nix
+        pythonEnv
+      ]}:$PATH
+      exec python3 ${builtins.toString ./update.py} ${builtins.toString ./.}
+    '';
+  };
+
   meta = {
     description = "The core APIs of the Emacs binding for tree-sitter.";
     license = lib.licenses.mit;

pkgs/applications/editors/emacs/elisp-packages/tsc/update.py

@@ -0,0 +1,122 @@
+#!/usr/bin/env python3
+from textwrap import dedent
+from os.path import (
+    abspath,
+    dirname,
+    join,
+)
+from typing import (
+    Dict,
+    Any,
+)
+import subprocess
+import tempfile
+import json
+import sys
+import re
+
+import requests
+
+
+def eval_drv(nixpkgs: str, expr: str) -> Any:
+    expr = "\n".join(
+        (
+            "with (import %s {});" % nixpkgs,
+            expr,
+        )
+    )
+
+    with tempfile.NamedTemporaryFile(mode="w") as f:
+        f.write(dedent(expr))
+        f.flush()
+        p = subprocess.run(
+            ["nix-instantiate", "--json", f.name], stdout=subprocess.PIPE, check=True
+        )
+
+    return p.stdout.decode().strip()
+
+
+def get_src(tag_name: str) -> Dict[str, str]:
+    p = subprocess.run(
+        [
+            "nix-prefetch-github",
+            "--rev",
+            tag_name,
+            "--json",
+            "emacs-tree-sitter",
+            "elisp-tree-sitter",
+        ],
+        stdout=subprocess.PIPE,
+        check=True,
+    )
+    src = json.loads(p.stdout)
+
+    fields = ["owner", "repo", "rev", "sha256"]
+
+    return {f: src[f] for f in fields}
+
+
+def get_cargo_sha256(drv_path: str):
+    # Note: No check=True since we expect this command to fail
+    p = subprocess.run(["nix-store", "-r", drv_path], stderr=subprocess.PIPE)
+
+    stderr = p.stderr.decode()
+    lines = iter(stderr.split("\n"))
+
+    for l in lines:
+        if l.startswith("error: hash mismatch in fixed-output derivation"):
+            break
+    else:
+        raise ValueError("Did not find expected hash mismatch message")
+
+    for l in lines:
+        m = re.match(r"\s+got:\s+(.+)$", l)
+        if m:
+            return m.group(1)
+
+    raise ValueError("Could not extract actual sha256 hash: ", stderr)
+
+
+if __name__ == "__main__":
+    cwd = sys.argv[1]
+
+    nixpkgs = abspath(join(cwd, "../../../../../.."))
+
+    tag_name = requests.get(
+        "https://api.github.com/repos/emacs-tree-sitter/elisp-tree-sitter/releases/latest"
+    ).json()["tag_name"]
+
+    src = get_src(tag_name)
+
+    with tempfile.NamedTemporaryFile(mode="w") as f:
+        json.dump(src, f)
+        f.flush()
+
+        drv_path = eval_drv(
+            nixpkgs,
+            """
+        rustPlatform.buildRustPackage {
+          pname = "tsc-dyn";
+          version = "%s";
+          nativeBuildInputs = [ clang ];
+          src = fetchFromGitHub (lib.importJSON %s);
+          sourceRoot = "source/core";
+          cargoSha256 = lib.fakeSha256;
+        }
+        """
+            % (tag_name, f.name),
+        )
+
+    cargo_sha256 = get_cargo_sha256(drv_path)
+
+    with open(join(cwd, "src.json"), mode="w") as f:
+        json.dump(
+            {
+                "src": src,
+                "version": tag_name,
+                "cargoSha256": cargo_sha256,
+            },
+            f,
+            indent=2,
+        )
+        f.write("\n")