ceph: arrow 19 compilation fix with protobuf 30; snappy: restore of RTTI patch (#427905)

pkgs/by-name/sn/snappy/package.nix

@@ -3,6 +3,7 @@
   stdenv,
   fetchFromGitHub,
   cmake,
+  fetchpatch,
   static ? stdenv.hostPlatform.isStatic,
 }:
 
@@ -19,6 +20,22 @@ stdenv.mkDerivation rec {
 
   patches = [
     ./revert-PUBLIC.patch
+    # Re-enable RTTI, without which other applications can't subclass snappy::Source
+    # While the patch was rejected upstream, it does not make it any less necessary to carry forward.
+    # ==> lack of RTTI *breaks* Ceph (and others) <==
+    #
+    # https://tracker.ceph.com/issues/53060
+    # https://build.opensuse.org/package/show/openSUSE:Factory/snappy
+    #
+    # Should this patch fail to apply use the above site to get the updated patch (rev in the url below).
+    # On the page there's a "latest revision" section which lists the last request which was merged into it.
+    # Click the "Request <insert number>" link, then view any file using "View file", and copy the rev from your address bar.
+    # For a different revision (in case nixpkgs is behind or something) you can go through the full revision history.
+    # Should the patch not be available for the nixpkgs version, ideally wait until the patch becomes available before bumping, or vendor it if necessary.
+    (fetchpatch {
+      url = "https://build.opensuse.org/public/source/openSUSE:Factory/snappy/reenable-rtti.patch?rev=e3449869b466869fc6b8a03a1a528fa6";
+      hash = "sha256-JhVhkHh7XPx1Bzf5xnOgWLgwh1oihX3O+emQWzE4Dho=";
+    })
   ];
 
   outputs = [

pkgs/tools/filesystems/ceph/arrow-cpp-19.nix

@@ -8,6 +8,7 @@
   stdenv,
   lib,
   fetchurl,
+  fetchpatch2,
   fetchFromGitHub,
   fixDarwinDylibNames,
   autoconf,
@@ -42,7 +43,7 @@
   openssl,
   perl,
   pkg-config,
-  protobuf_29,
+  protobuf,
   python3,
   rapidjson,
   re2,
@@ -67,9 +68,6 @@
 }:
 
 let
-  # https://github.com/apache/arrow/issues/45807
-  protobuf = protobuf_29;
-
   arrow-testing = fetchFromGitHub {
     name = "arrow-testing";
     owner = "apache";
@@ -101,6 +99,15 @@ stdenv.mkDerivation (finalAttrs: {
 
   sourceRoot = "${finalAttrs.src.name}/cpp";
 
+  patches = [
+    (fetchpatch2 {
+      name = "protobuf-30-compat.patch";
+      url = "https://github.com/apache/arrow/pull/46136.patch";
+      hash = "sha256-WTpe/eT3himlCHN/R78w1sF0HG859mE2ZN70U+9N8Ag=";
+      stripLen = 1;
+    })
+  ];
+
   # versions are all taken from
   # https://github.com/apache/arrow/blob/apache-arrow-${version}/cpp/thirdparty/versions.txt