fix(postgis): remove custom sfcgal package dependency

Updated postgis.nix to use nixpkgs sfcgal instead of our custom package,
eliminating the need to maintain a separate sfcgal build definition.

Author: yvan-sraka

nix/ext/pgrouting.nix

@@ -49,13 +49,18 @@ let
         inherit hash;
       };
 
+      patches = lib.optionals (version == "3.4.1" && lib.versionAtLeast postgresql.version "17") [
+        ./pgrouting/pgrouting-3.4.1-pg17.patch
+      ];
+
       #disable compile time warnings for incompatible pointer types only on macos and pg16
       NIX_CFLAGS_COMPILE = lib.optionalString (
         stdenv.isDarwin && lib.versionAtLeast postgresql.version "16"
       ) "-Wno-error=int-conversion -Wno-error=incompatible-pointer-types";
 
       cmakeFlags = [
         "-DPOSTGRESQL_VERSION=${postgresql.version}"
+        "-DCMAKE_POLICY_VERSION_MINIMUM=3.5"
       ]
       ++ lib.optionals (stdenv.isDarwin && lib.versionAtLeast postgresql.version "16") [
         "-DCMAKE_MACOSX_RPATH=ON"

nix/ext/pgrouting/pgrouting-3.4.1-pg17.patch

@@ -0,0 +1,39 @@
+From ce195442200452ae50b63528647e3837e9f121e0 Mon Sep 17 00:00:00 2001
+From: Yvan Sraka <yvan@sraka.xyz>
+Date: Thu, 4 Dec 2025 19:33:44 +0100
+Subject: [PATCH] Fix PostgreSQL 17 compatibility in SPI_getvalue calls
+
+SPI_getvalue already returns a char* in PostgreSQL 17, so wrapping
+it in DatumGetCString (which expects a Datum) causes a compilation
+error. This patch removes the unnecessary DatumGetCString wrapper
+in both get_check_data.c and trsp.c files.
+---
+ src/common/get_check_data.c | 2 +-
+ src/trsp/trsp.c             | 4 ++--
+ 2 files changed, 3 insertions(+), 3 deletions(-)
+
+diff --git a/src/common/get_check_data.c b/src/common/get_check_data.c
+index 85ea70d..82a81d1 100644
+--- a/src/common/get_check_data.c
++++ b/src/common/get_check_data.c
+@@ -304,5 +304,5 @@ pgr_SPI_getFloat8(HeapTuple *tuple, TupleDesc *tupdesc, Column_info_t info) {
+  */
+ char*
+ pgr_SPI_getText(HeapTuple *tuple, TupleDesc *tupdesc,  Column_info_t info) {
+-    return DatumGetCString(SPI_getvalue(*tuple, *tupdesc, info.colNumber));
++    return SPI_getvalue(*tuple, *tupdesc, info.colNumber);
+ }
+diff --git a/src/trsp/trsp.c b/src/trsp/trsp.c
+index 7f9397a..52b68dd 100644
+--- a/src/trsp/trsp.c
++++ b/src/trsp/trsp.c
+@@ -114,8 +114,8 @@ fetch_restrict(HeapTuple *tuple, TupleDesc *tupdesc,
+   if (isnull)
+     elog(ERROR, "to_cost contains a null value");
+   rest->to_cost = DatumGetFloat8(binval);
+-  char *str = DatumGetCString(SPI_getvalue(*tuple, *tupdesc,
+-       restrict_columns->via_path));
++  char *str = SPI_getvalue(*tuple, *tupdesc,
++       restrict_columns->via_path);
+ 
+   // PGR_DBG("restriction: %f, %i, %s", rest->to_cost, rest->target_id, str);

nix/ext/postgis.nix

@@ -16,10 +16,10 @@
   nixosTests,
   callPackage,
   buildEnv,
+  sfcgal,
 }:
 
 let
-  sfcgal = callPackage ../packages/sfcgal.nix { };
   gdal = callPackage ./gdal.nix { inherit postgresql; };
   pname = "postgis";
 

nix/packages/default.nix

@@ -48,7 +48,6 @@
           pg_prove = pkgs.perlPackages.TAPParserSourceHandlerpgTAP;
           pg_regress = makePgRegress activeVersion;
           run-testinfra = pkgs.callPackage ./run-testinfra.nix { };
-          sfcgal = pkgs.callPackage ./sfcgal.nix { };
           show-commands = pkgs.callPackage ./show-commands.nix { };
           start-client = pkgs.callPackage ./start-client.nix {
             psql_15 = self'.packages."psql_15/bin";

nix/packages/sfcgal.nix

@@ -19,12 +19,12 @@ select * from pgr_dijkstra(
   1, -- start node
   4  -- end node
 );
- seq | path_seq | start_vid | end_vid | node | edge | cost | agg_cost 
------+----------+-----------+---------+------+------+------+----------
-   1 |        1 |         1 |       4 |    1 |    1 |    1 |        0
-   2 |        2 |         1 |       4 |    2 |    2 |    1 |        1
-   3 |        3 |         1 |       4 |    3 |    3 |    1 |        2
-   4 |        4 |         1 |       4 |    4 |   -1 |    0 |        3
+ seq | path_seq | node | edge | cost | agg_cost 
+-----+----------+------+------+------+----------
+   1 |        1 |    1 |    1 |    1 |        0
+   2 |        2 |    2 |    2 |    1 |        1
+   3 |        3 |    3 |    3 |    1 |        2
+   4 |        4 |    4 |   -1 |    0 |        3
 (4 rows)
 
 drop schema v cascade;