let

  generic =
    # dependencies
    {
      stdenv,
      lib,
      fetchurl,
      fetchpatch,
      makeWrapper,
      glibc,
      zlib,
      readline,
      openssl,
      icu,
      lz4,
      zstd,
      systemdLibs,
      libuuid,
      pkg-config,
      libxml2,
      tzdata,
      libkrb5,
      substituteAll,
      darwin,
      linux-pam,
      bison,
      flex,
      perl,
      docbook_xml_dtd_45,
      docbook-xsl-nons,
      libxslt,

      removeReferencesTo,
      writeShellScriptBin,

      systemdSupport ? lib.meta.availableOn stdenv.hostPlatform systemdLibs,
      gssSupport ? with stdenv.hostPlatform; !isWindows && !isStatic,

      # for postgresql.pkgs
      self,
      newScope,
      buildEnv,
      stdenvNoCC,
      postgresqlTestHook,

      # source specification
      version,
      hash,
      muslPatches ? { },

      # for tests
      testers,
      nixosTests,

      # JIT
      jitSupport,
      nukeReferences,
      llvmPackages,
      overrideCC,

      # PL/Python
      pythonSupport ? false,
      python3,
    }@args:
    let
      atLeast = lib.versionAtLeast version;
      olderThan = lib.versionOlder version;
      lz4Enabled = atLeast "14";
      zstdEnabled = atLeast "15";

      dlSuffix = if olderThan "16" then ".so" else stdenv.hostPlatform.extensions.sharedLibrary;

      pname = "postgresql";

      stdenv' =
        if jitSupport && !stdenv.cc.isClang then
          overrideCC llvmPackages.stdenv (
            llvmPackages.stdenv.cc.override {
              # LLVM bintools are not used by default, but are needed to make -flto work below.
              bintools = llvmPackages.bintools;
            }
          )
        else
          stdenv;

      pg_config = writeShellScriptBin "pg_config" (builtins.readFile ./pg_config.sh);
    in
    stdenv'.mkDerivation (finalAttrs: {
      inherit version;
      pname = pname + lib.optionalString jitSupport "-jit";

      src = fetchurl {
        url = "mirror://postgresql/source/v${version}/${pname}-${version}.tar.bz2";
        inherit hash;
      };

      __structuredAttrs = true;

      hardeningEnable = lib.optionals (!stdenv'.cc.isClang) [ "pie" ];

      outputs = [
        "out"
        "dev"
        "doc"
        "lib"
        "man"
      ];
      outputChecks.out = {
        disallowedReferences = [
          "dev"
          "doc"
          "man"
        ];
        disallowedRequisites =
          [
            stdenv'.cc
          ]
          ++ (map lib.getDev (builtins.filter (drv: drv ? "dev") finalAttrs.buildInputs))
          ++ lib.optionals jitSupport [
            llvmPackages.llvm.out
          ];
      };
      outputChecks.lib = {
        disallowedReferences = [
          "out"
          "dev"
          "doc"
          "man"
        ];
        disallowedRequisites =
          [
            stdenv'.cc
          ]
          ++ (map lib.getDev (builtins.filter (drv: drv ? "dev") finalAttrs.buildInputs))
          ++ lib.optionals jitSupport [
            llvmPackages.llvm.out
          ];
      };

      buildInputs =
        [
          zlib
          readline
          openssl
          (libxml2.override { enableHttp = true; })
          icu
          libuuid
        ]
        ++ lib.optionals jitSupport [ llvmPackages.llvm ]
        ++ lib.optionals lz4Enabled [ lz4 ]
        ++ lib.optionals zstdEnabled [ zstd ]
        ++ lib.optionals systemdSupport [ systemdLibs ]
        ++ lib.optionals pythonSupport [ python3 ]
        ++ lib.optionals gssSupport [ libkrb5 ]
        ++ lib.optionals stdenv'.hostPlatform.isLinux [ linux-pam ];

      nativeBuildInputs =
        [
          makeWrapper
          pkg-config
          removeReferencesTo
        ]
        ++ lib.optionals jitSupport [
          llvmPackages.llvm.dev
          nukeReferences
        ]
        ++ lib.optionals (atLeast "17") [
          bison
          flex
          perl
          docbook_xml_dtd_45
          docbook-xsl-nons
          libxslt
        ];

      enableParallelBuilding = true;

      separateDebugInfo = true;

      buildFlags = [ "world" ];

      # libpgcommon.a and libpgport.a contain all paths returned by pg_config and are linked
      # into all binaries. However, almost no binaries actually use those paths. The following
      # flags will remove unused sections from all shared libraries and binaries - including
      # those paths. This avoids a lot of circular dependency problems with different outputs,
      # and allows splitting them cleanly.
      env.CFLAGS =
        "-fdata-sections -ffunction-sections"
        + (if stdenv'.cc.isClang then " -flto" else " -fmerge-constants -Wl,--gc-sections");

      configureFlags =
        [
          "--with-openssl"
          "--with-libxml"
          "--with-icu"
          "--sysconfdir=/etc"
          "--with-system-tzdata=${tzdata}/share/zoneinfo"
          "--enable-debug"
          (lib.optionalString systemdSupport "--with-systemd")
          "--with-uuid=e2fs"
        ]
        ++ lib.optionals lz4Enabled [ "--with-lz4" ]
        ++ lib.optionals zstdEnabled [ "--with-zstd" ]
        ++ lib.optionals gssSupport [ "--with-gssapi" ]
        ++ lib.optionals pythonSupport [ "--with-python" ]
        ++ lib.optionals jitSupport [ "--with-llvm" ]
        ++ lib.optionals stdenv'.hostPlatform.isLinux [ "--with-pam" ]
        # This could be removed once the upstream issue is resolved:
        # https://postgr.es/m/flat/427c7c25-e8e1-4fc5-a1fb-01ceff185e5b%40technowledgy.de
        ++ lib.optionals (stdenv'.hostPlatform.isDarwin && atLeast "16") [
          "LDFLAGS_EX_BE=-Wl,-export_dynamic"
        ]
        ++ lib.optionals (atLeast "17") [ "--without-perl" ];

      patches =
        [
          (
            if atLeast "16" then
              ./patches/relative-to-symlinks-16+.patch
            else
              ./patches/relative-to-symlinks.patch
          )
          (
            if atLeast "15" then
              ./patches/empty-pg-config-view-15+.patch
            else
              ./patches/empty-pg-config-view.patch
          )
          ./patches/less-is-more.patch
          ./patches/paths-for-split-outputs.patch
          ./patches/paths-with-postgresql-suffix.patch

          (substituteAll {
            src = ./patches/locale-binary-path.patch;
            locale = "${
              if stdenv.hostPlatform.isDarwin then darwin.adv_cmds else lib.getBin stdenv.cc.libc
            }/bin/locale";
          })
        ]
        ++ lib.optionals stdenv'.hostPlatform.isMusl (
          # Using fetchurl instead of fetchpatch on purpose: https://github.com/NixOS/nixpkgs/issues/240141
          map fetchurl (lib.attrValues muslPatches)
        )
        ++ lib.optionals stdenv'.hostPlatform.isLinux [
          ./patches/socketdir-in-run-13+.patch
        ]
        ++ lib.optionals (stdenv'.hostPlatform.isDarwin && olderThan "16") [
          ./patches/export-dynamic-darwin-15-.patch
        ];

      installTargets = [ "install-world" ];

      postPatch = ''
        substituteInPlace "src/Makefile.global.in" --subst-var out
        # Hardcode the path to pgxs so pg_config returns the path in $dev
        substituteInPlace "src/common/config_info.c" --subst-var dev
      '';

      postInstall =
        ''
          moveToOutput "bin/ecpg" "$dev"
          moveToOutput "lib/pgxs" "$dev"

          # Pretend pg_config is located in $out/bin to return correct paths, but
          # actually have it in -dev to avoid pulling in all other outputs. See the
          # pg_config.sh script's comments for details.
          moveToOutput "bin/pg_config" "$dev"
          install -c -m 755 "${pg_config}"/bin/pg_config "$out/bin/pg_config"
          wrapProgram "$dev/bin/pg_config" --argv0 "$out/bin/pg_config"

          # postgres exposes external symbols get_pkginclude_path and similar. Those
          # can't be stripped away by --gc-sections/LTO, because they could theoretically
          # be used by dynamically loaded modules / extensions. To avoid circular dependencies,
          # references to -dev, -doc and -man are removed here. References to -lib must be kept,
          # because there is a realistic use-case for extensions to locate the /lib directory to
          # load other shared modules.
          remove-references-to -t "$dev" -t "$doc" -t "$man" "$out/bin/postgres"

          if [ -z "''${dontDisableStatic:-}" ]; then
            # Remove static libraries in case dynamic are available.
            for i in $lib/lib/*.a; do
              name="$(basename "$i")"
              ext="${stdenv'.hostPlatform.extensions.sharedLibrary}"
              if [ -e "$lib/lib/''${name%.a}$ext" ] || [ -e "''${i%.a}$ext" ]; then
                rm "$i"
              fi
            done
          fi
          # The remaining static libraries are libpgcommon.a, libpgport.a and related.
          # Those are only used when building e.g. extensions, so go to $dev.
          moveToOutput "lib/*.a" "$dev"
        ''
        + lib.optionalString jitSupport ''
          # In the case of JIT support, prevent useless dependencies on header files
          find "$out/lib" -iname '*.bc' -type f -exec nuke-refs '{}' +

          # Stop lib depending on the -dev output of llvm
          remove-references-to -t ${llvmPackages.llvm.dev} "$out/lib/llvmjit${dlSuffix}"
        '';

      postFixup = lib.optionalString stdenv'.hostPlatform.isGnu ''
        # initdb needs access to "locale" command from glibc.
        wrapProgram $out/bin/initdb --prefix PATH ":" ${glibc.bin}/bin
      '';

      doCheck = !stdenv'.hostPlatform.isDarwin;
      # autodetection doesn't seem to able to find this, but it's there.
      checkTarget = "check-world";

      passthru =
        let
          this = self.callPackage generic args;
          jitToggle = this.override {
            jitSupport = !jitSupport;
          };
        in
        {
          inherit dlSuffix;

          psqlSchema = lib.versions.major version;

          withJIT = if jitSupport then this else jitToggle;
          withoutJIT = if jitSupport then jitToggle else this;

          pkgs =
            let
              scope = {
                inherit jitSupport;
                inherit (llvmPackages) llvm;
                postgresql = this;
                stdenv = stdenv';
                postgresqlTestExtension =
                  {
                    finalPackage,
                    withPackages ? [ ],
                    ...
                  }@extraArgs:
                  stdenvNoCC.mkDerivation (
                    {
                      name = "${finalPackage.name}-test-extension";
                      dontUnpack = true;
                      doCheck = true;
                      nativeCheckInputs = [
                        postgresqlTestHook
                        (this.withPackages (ps: [ finalPackage ] ++ (map (p: ps."${p}") withPackages)))
                      ];
                      failureHook = "postgresqlStop";
                      postgresqlTestUserOptions = "LOGIN SUPERUSER";
                      passAsFile = [ "sql" ];
                      checkPhase = ''
                        runHook preCheck
                        psql -a -v ON_ERROR_STOP=1 -f "$sqlPath"
                        runHook postCheck
                      '';
                      installPhase = "touch $out";
                    }
                    // extraArgs
                  );
                buildPostgresqlExtension = newSuper.callPackage ./buildPostgresqlExtension.nix { };
              };
              newSelf = self // scope;
              newSuper = {
                callPackage = newScope (scope // this.pkgs);
              };
            in
            import ./ext newSelf newSuper;

          withPackages = postgresqlWithPackages {
            inherit buildEnv;
            postgresql = this;
          };

          tests =
            {
              postgresql = nixosTests.postgresql.postgresql.passthru.override finalAttrs.finalPackage;
              postgresql-tls-client-cert = nixosTests.postgresql.postgresql-tls-client-cert.passthru.override finalAttrs.finalPackage;
              postgresql-wal-receiver = nixosTests.postgresql.postgresql-wal-receiver.passthru.override finalAttrs.finalPackage;
              pkg-config = testers.testMetaPkgConfig finalAttrs.finalPackage;
            }
            // lib.optionalAttrs jitSupport {
              postgresql-jit = nixosTests.postgresql.postgresql-jit.passthru.override finalAttrs.finalPackage;
            };
        };

      meta = with lib; {
        homepage = "https://www.postgresql.org";
        description = "Powerful, open source object-relational database system";
        license = licenses.postgresql;
        changelog = "https://www.postgresql.org/docs/release/${finalAttrs.version}/";
        maintainers = with maintainers; teams.postgres.members;
        pkgConfigModules = [
          "libecpg"
          "libecpg_compat"
          "libpgtypes"
          "libpq"
        ];
        platforms = platforms.unix;

        # JIT support doesn't work with cross-compilation. It is attempted to build LLVM-bytecode
        # (`%.bc` is the corresponding `make(1)`-rule) for each sub-directory in `backend/` for
        # the JIT apparently, but with a $(CLANG) that can produce binaries for the build, not the
        # host-platform.
        #
        # I managed to get a cross-build with JIT support working with
        # `depsBuildBuild = [ llvmPackages.clang ] ++ buildInputs`, but considering that the
        # resulting LLVM IR isn't platform-independent this doesn't give you much.
        # In fact, I tried to test the result in a VM-test, but as soon as JIT was used to optimize
        # a query, postgres would coredump with `Illegal instruction`.
        broken = jitSupport && !stdenv.hostPlatform.canExecute stdenv.buildPlatform;
      };
    });

  postgresqlWithPackages =
    { postgresql, buildEnv }:
    f:
    let
      installedExtensions = f postgresql.pkgs;
    in
    buildEnv {
      name = "${postgresql.pname}-and-plugins-${postgresql.version}";
      paths = installedExtensions ++ [
        postgresql
        postgresql.man # in case user installs this into environment
      ];

      pathsToLink = [ "/" ];

      passthru = {
        inherit installedExtensions;
        inherit (postgresql)
          psqlSchema
          version
          ;

        withJIT = postgresqlWithPackages {
          inherit buildEnv;
          postgresql = postgresql.withJIT;
        } f;
        withoutJIT = postgresqlWithPackages {
          inherit buildEnv;
          postgresql = postgresql.withoutJIT;
        } f;
      };
    };

in
# passed by <major>.nix
versionArgs:
# passed by default.nix
{ self, ... }@defaultArgs:
self.callPackage generic (defaultArgs // versionArgs)