From b722b9ddffa719177373d0f1f299c8528e5fed85 Mon Sep 17 00:00:00 2001
From: Jules Aguillon <jules@j3s.fr>
Date: Tue, 4 Jul 2023 14:05:47 +0200
Subject: [PATCH] ocamlPackages.logs: Optional dependency on lwt and cmdliner

These are optional dependencies for the library. Making them optional is
useful to reduce the size of other packages.

By default, the dependencies are all provided and the output is
unchanged.
---
 .../ocaml-modules/logs/default.nix            | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/pkgs/development/ocaml-modules/logs/default.nix b/pkgs/development/ocaml-modules/logs/default.nix
index 0b8ffed91e49..bd7326883829 100644
--- a/pkgs/development/ocaml-modules/logs/default.nix
+++ b/pkgs/development/ocaml-modules/logs/default.nix
@@ -3,10 +3,23 @@
 , fmtSupport ? lib.versionAtLeast ocaml.version "4.08"
 , js_of_ocaml
 , jsooSupport ? true
+, lwtSupport ? true
+, cmdlinerSupport ? true
 }:
 let
   pname = "logs";
   webpage = "https://erratique.ch/software/${pname}";
+
+  optional_deps = [
+    { pkg = js_of_ocaml; enable_flag = "--with-js_of_ocaml"; enabled = jsooSupport; }
+    { pkg = fmt; enable_flag = "--with-fmt"; enabled = fmtSupport; }
+    { pkg = lwt; enable_flag = "--with-lwt"; enabled = lwtSupport; }
+    { pkg = cmdliner; enable_flag = "--with-cmdliner"; enabled = cmdlinerSupport; }
+  ];
+  enable_flags =
+    lib.concatMap (d: [ d.enable_flag (lib.boolToString d.enabled)]) optional_deps;
+  optional_buildInputs =
+    map (d: d.pkg) (lib.filter (d: d.enabled) optional_deps);
 in
 
 if lib.versionOlder ocaml.version "4.03"
@@ -23,14 +36,12 @@ stdenv.mkDerivation rec {
   };
 
   nativeBuildInputs = [ ocaml findlib ocamlbuild topkg ];
-  buildInputs = [ cmdliner lwt topkg ]
-    ++ lib.optional fmtSupport fmt
-    ++ lib.optional jsooSupport js_of_ocaml;
+  buildInputs = [ topkg ] ++ optional_buildInputs;
   propagatedBuildInputs = [ result ];
 
   strictDeps = true;
 
-  buildPhase = "${topkg.run} build --with-js_of_ocaml ${lib.boolToString jsooSupport} --with-fmt ${lib.boolToString fmtSupport}";
+  buildPhase = "${topkg.run} build ${lib.escapeShellArgs enable_flags}";
 
   inherit (topkg) installPhase;