push sheeet

pkgs/build-support/fetchhg/builder.sh

@@ -0,0 +1,6 @@
+echo "getting $url${rev:+ ($rev)} into $out"
+
+hg clone --insecure "$url" hg-clone
+
+hg archive -q$subrepoClause -y ${rev:+-r "$rev"} --cwd hg-clone $out
+rm -f $out/.hg_archival.txt

pkgs/build-support/fetchhg/default.nix

@@ -0,0 +1,48 @@
+{
+  lib,
+  stdenvNoCC,
+  mercurial,
+}:
+
+lib.extendMkDerivation {
+  constructDrv = stdenvNoCC.mkDerivation;
+
+  extendDrvArgs =
+    finalAttrs:
+    {
+      name ? null,
+      url,
+      rev ? null,
+      sha256 ? null,
+      hash ? null,
+      fetchSubrepos ? false,
+      preferLocalBuild ? true,
+    }:
+    # TODO: statically check if mercurial has https support if the url starts with https.
+    {
+      name = "hg-archive" + (lib.optionalString (name != null) "-${name}");
+      builder = ./builder.sh;
+      nativeBuildInputs = [ mercurial ];
+
+      impureEnvVars = lib.fetchers.proxyImpureEnvVars;
+
+      subrepoClause = lib.optionalString fetchSubrepos "S";
+
+      outputHashAlgo = if finalAttrs.hash != null && finalAttrs.hash != "" then null else "sha256";
+      outputHashMode = "recursive";
+      outputHash = lib.throwIf (hash != null && sha256 != null) "Only one of sha256 or hash can be set" (
+        if finalAttrs.hash != null then
+          finalAttrs.hash
+        else if sha256 != null then
+          sha256
+        else
+          ""
+      );
+
+      inherit url rev hash;
+      inherit preferLocalBuild;
+    };
+
+  # No ellipsis
+  inheritFunctionArgs = false;
+}

pkgs/build-support/fetchhg/nix-prefetch-hg

@@ -0,0 +1,84 @@
+#! /usr/bin/env bash
+set -e
+
+url=$1
+rev=$2
+expHash=$3
+
+hashType="${NIX_HASH_ALGO:-sha256}"
+hashFormat=${hashFormat:-"--base32"}
+rev="${rev:-tip}"
+
+LOG() {
+  echo "$@" >&2
+}
+
+die() {
+  LOG "$@"
+  exit 1
+}
+
+if [[ -z "$url" || "$url" == "--help" ]]; then
+    die "Usage: nix-prefetch-hg URL [rev [EXPECTED-HASH]]"
+fi
+
+if [[ "${fetchSubrepos:-0}" == 1 ]]; then
+    subrepoClause=S
+else
+    subrepoClause=
+fi
+
+# If the hash was given, a file with that hash may already be in the
+# store.
+if [[ -n "$expHash" ]]; then
+    finalPath=$(nix-store --print-fixed-path --recursive "$hashType" "$expHash" hg-archive)
+    if ! nix-store --check-validity "$finalPath" 2> /dev/null; then
+        finalPath=
+    fi
+    hash="$expHash"
+fi
+
+
+# If we don't know the hash or a path with that hash doesn't exist,
+# download the file and add it to the store.
+if [[ -z "$finalPath" ]]; then
+    # nix>=2.20 rejects adding symlinked paths to the store, so use realpath
+    # to resolve to a physical path. https://github.com/NixOS/nix/issues/11941
+    tmpPath="$(realpath "$(mktemp -d --tmpdir hg-checkout-tmp-XXXXXXXX)")"
+    cleanup() { x=$?; rm -rf "$tmpPath"; exit $x; }; trap cleanup EXIT
+
+    tmpArchive="$tmpPath/hg-archive"
+
+    # Perform the checkout.
+    if [[ "$url" != /* ]]; then
+      tmpClone="$tmpPath/hg-clone"
+      hg clone -q -y -U "$url" "$tmpClone" >&2
+    else
+      tmpClone=$url
+    fi
+    hg archive -q$subrepoClause -y -r "$rev" --cwd "$tmpClone" "$tmpArchive"
+    rm -f "$tmpArchive/.hg_archival.txt"
+
+    LOG "hg revision is $(cd "$tmpClone"; hg id -r "$rev" -i)"
+
+    # Compute the hash.
+    hash=$(nix-hash --type "$hashType" "$hashFormat" "$tmpArchive")
+    if [[ -z "$QUIET" ]]; then LOG "hash is $hash"; fi
+
+    # Add the downloaded file to the Nix store.
+    finalPath=$(nix-store --add-fixed --recursive "$hashType" "$tmpArchive")
+
+    if [[ -n "$expHash" && "$expHash" != "$hash" ]]; then
+        die "ERROR: hash mismatch for URL \`$url'"
+    fi
+
+
+fi
+
+if [[ -z "$QUIET" ]]; then LOG "path is $finalPath"; fi
+
+echo "$hash"
+
+if [[ -n "$PRINT_PATH" ]]; then
+    echo "$finalPath"
+fi