Add compiler constraints

So now you can write:

ocaml-version: [ >= "4.00.0" ]

in a package description (a .opam file) and the package will only be considered in the constraint solving if the current compiler version satisfies the constraint.

src/client.ml

@@ -685,6 +685,11 @@ let get_archive t nv =
   Filename.link src dst;
   dst
 
+let current_ocaml_version t =
+  let alias = File.Config.ocaml_version t.config in
+  let aliases = File.Aliases.read (Path.G.aliases t.global) in
+  List.assoc alias aliases
+
 type env = {
   add_to_env : (string * string) list;
   add_to_path: dirname;
@@ -704,8 +709,7 @@ let expand_env t env =
 
 (* XXX: We should get the ones defined in the dependents packages as well *)
 let get_env t =
-  let aliases = File.Aliases.read (Path.G.aliases t.global) in
-  let ocaml_version = List.assoc (File.Config.ocaml_version t.config) aliases in 
+  let ocaml_version = current_ocaml_version t in 
   let comp_f = Path.G.compiler t.global ocaml_version in
   let comp = File.Comp.read comp_f in
 
@@ -927,7 +931,22 @@ module Heuristic = struct
       )
 
   let resolve action_k t l_request =
-    let l_pkg = NV.Set.fold (fun nv l -> debpkg_of_nv action_k t nv :: l) t.available [] in
+    (* Remove the package which does not fullfil the compiler constraints *)
+    let ocaml_version =
+      if File.Config.ocaml_version t.config = Alias.of_string Globals.default_compiler_version then
+        match OCaml_V.current () with
+        | None   -> assert false
+        | Some v -> v
+      else
+        current_ocaml_version t in
+    let filter nv =
+      let opam = File.OPAM.read (Path.G.opam t.global nv) in
+      match File.OPAM.ocaml_version opam with
+      | None       -> true
+      | Some (r,v) -> OCaml_V.compare ocaml_version r v in
+    let available = NV.Set.filter filter t.available in
+
+    let l_pkg = NV.Set.fold (fun nv l -> debpkg_of_nv action_k t nv :: l) available [] in
 
     match
       List.fold_left 
@@ -1153,11 +1172,8 @@ let config request =
       Globals.msg "%s\n" (String.concat " " includes)
 
   | Compil c ->
-      let comp =
-        let alias = File.Config.ocaml_version t.config in
-        let aliases = File.Aliases.read (Path.G.aliases t.global) in
-        let oversion = List.assoc alias aliases in
-        File.Comp.safe_read (Path.G.compiler t.global oversion) in
+      let oversion = current_ocaml_version t in
+      let comp = File.Comp.read (Path.G.compiler t.global oversion) in
       let names =
         List.filter
           (fun n -> NV.Set.exists (fun nv -> NV.name nv = n) t.installed)

src/file.ml

@@ -332,6 +332,7 @@ module OPAM = struct
     libraries  : section list;
     syntax     : section list;
     others     : (string * value) list;
+    ocaml_version: ocaml_constraint option;
   }
 
   let empty = {
@@ -347,6 +348,7 @@ module OPAM = struct
     libraries  = [];
     syntax     = [];
     others     = [];
+    ocaml_version = None;
   }
 
   let create nv =
@@ -367,6 +369,7 @@ module OPAM = struct
   let s_license     = "license"
   let s_authors     = "authors"
   let s_homepage    = "homepage"
+  let s_ocaml_version = "ocaml-version"
 
   (* to convert to cudf *)
   (* see [Debcudf.add_inst] for more details about the format *)
@@ -387,6 +390,7 @@ module OPAM = struct
     s_conflicts;
     s_libraries;
     s_syntax;
+    s_ocaml_version;
   ]
 
   let valid_fields =
@@ -407,6 +411,7 @@ module OPAM = struct
   let conflicts t = t.conflicts
   let libraries t = t.libraries
   let syntax t = t.syntax
+  let ocaml_version t = t.ocaml_version
 
   let with_depends t depends = { t with depends }
   let with_build t build = { t with build }
@@ -455,7 +460,12 @@ module OPAM = struct
             Variable (s_conflicts, make_and_formula t.conflicts);
             Variable (s_libraries, make_list (Section.to_string |> make_string) t.libraries);
             Variable (s_syntax, make_list (Section.to_string |> make_string) t.syntax);
-          ] @ List.map (fun (s, v) -> Variable (s, v)) t.others;
+          ] @ (
+            match t.ocaml_version with
+            | None   -> []
+            | Some v -> [ Variable (s_ocaml_version, make_constraint v) ]
+          ) @
+            List.map (fun (s, v) -> Variable (s, v)) t.others;
         }
       ] 
     } in
@@ -492,13 +502,15 @@ module OPAM = struct
     let conflicts  = assoc_list s s_conflicts parse_and_formula in
     let libraries  = assoc_list s s_libraries (parse_list (parse_string |> Section.of_string)) in
     let syntax     = assoc_list s s_syntax (parse_list (parse_string |> Section.of_string)) in
+    let ocaml_version = assoc_option s s_ocaml_version parse_constraint in
     let others     =
       Utils.filter_map (function
         | Variable (x,v) -> if List.mem x useful_fields then None else Some (x,v)
         | _              -> None
       ) s in
     { name; version; maintainer; substs; build; remove;
-      depends; depopts; conflicts; libraries; syntax; others }
+      depends; depopts; conflicts; libraries; syntax; others;
+      ocaml_version; }
 end
 
 module Dot_install_raw = struct

src/file.mli

@@ -86,6 +86,9 @@ module OPAM: sig
   (** Package version *)
   val version: t -> version
 
+  (** Compiler constraint *)
+  val ocaml_version: t -> ocaml_constraint option
+
   (** Package maintainer *)
   val maintainer: t -> string
 

src/file_format.ml

@@ -323,3 +323,31 @@ let make_cnf_formula l =
       | _   -> (Group orl) :: cnf
     ) [] l in
   List cnf
+
+let parse_relop = function
+  | "="  -> `Eq
+  | ">=" -> `Geq
+  | ">"  -> `Gt
+  | "<=" -> `Leq
+  | "<"  -> `Lt
+  | _    -> invalid_arg "parse_relop"
+
+let parse_constraint = function
+  | List [ Symbol r; String v ] ->
+      (try (parse_relop r, Types.OCaml_V.of_string v)
+       with _ -> bad_format "Expecting a relop, got %s" r)
+  | x -> bad_format "Expecting a constraint, got %s" (kind x)
+
+let string_of_relop = function
+  | `Eq  -> "="
+  | `Geq -> ">="
+  | `Gt  -> ">"
+  | `Leq -> "<="
+  | `Lt  -> "<"
+  | _    -> invalid_arg "parse_relop"
+
+let make_constraint (r, v) =
+  List [
+    Symbol (string_of_relop r);
+    String (Types.OCaml_V.to_string v);
+  ]

src/file_format.mli

@@ -215,3 +215,9 @@ val make_and_formula : and_formula -> value
 
 (** Build a CNF formula *)
 val make_cnf_formula : cnf_formula -> value
+
+(** Parse a simple constraint *)
+val parse_constraint: value -> ocaml_constraint
+
+(** Build a simple constraint *)
+val make_constraint: ocaml_constraint -> value

src/types.ml

@@ -414,16 +414,31 @@ end
 
 type nv = NV.t
 
+type relop = [`Eq|`Geq|`Gt|`Leq|`Lt]
+
 (* OCaml version *)
 module OCaml_V: sig
   include Abstract
   val current: unit -> t option
+  val compare: t -> relop -> t -> bool
 end = struct
   include Base
+
   let current () =
     match Run.ocaml_version () with
     | None   -> None
     | Some o -> Some (of_string o)
+
+  let compare v1 r v2 =
+    let v1 = to_string v1 in
+    let v2 = to_string v2 in
+    match r with
+    | `Eq  -> Debian.Version.equal v1 v2
+    | `Geq -> Debian.Version.compare v1 v2 >= 0
+    | `Gt  -> Debian.Version.compare v1 v2 > 0
+    | `Leq -> Debian.Version.compare v1 v2 <= 0
+    | `Lt  -> Debian.Version.compare v1 v2 < 0
+
 end
 
 module Alias: Abstract = Base
@@ -714,3 +729,4 @@ let string_of_config = function
 
 type and_formula = Debian.Format822.vpkglist
 type cnf_formula = Debian.Format822.vpkgformula
+type ocaml_constraint = relop * OCaml_V.t

src/types.mli

@@ -251,12 +251,18 @@ end
 (** Shortcut to NV.t *)
 type nv = NV.t
 
+
+type relop = [`Eq|`Geq|`Gt|`Leq|`Lt]
+
 (** OCaml version *)
 module OCaml_V: sig
   include Abstract
 
   (** Return the version of the compiler currently installed *)
   val current: unit -> t option
+
+  (** Compare OCaml versions *)
+  val compare: t -> relop -> t -> bool
 end
 
 (** OPAM version *)
@@ -426,3 +432,4 @@ module Alias: Abstract
 
 type and_formula = Debian.Format822.vpkglist
 type cnf_formula = Debian.Format822.vpkgformula
+type ocaml_constraint = relop * OCaml_V.t

tests/Makefile

@@ -211,17 +211,19 @@ switch-alias:
 	$(OPAM) remove P3.1~weird-version.test P4.2
 	$(CHECK) -l switch-alias P1.1 P2.1
 	$(OPAM) switch -alias test $(OCAMLVERSION) -clone
-	$(CHECK) -l switch-alias P1.1 P2.1
-	$(OPAM) switch -list
+	$(CHECK) -l switch-alias-test P1.1 P2.1
+	$(OPAM) switch 4.00.0
+	$(OPAM) install P1
+	$(CHECK) -l switch-alias-4.00 P1.1
 
 switch-env-packages:
-	$(OPAM) switch dummy
+	$(OPAM) switch 3.12.1
 ifeq ($(REPOKIND), git)
 	$(CHECK) -l switch-env-packages P1.1 P2.1 P3.1~weird-version.test P4.3
 else
 	$(CHECK) -l switch-env-packages P1.2 P2.1 P3.1~weird-version.test P4.3
 endif
-	./test-TEST.sh $(OPAM_ROOT)/dummy/build/P4.3/P4.env "1"
+	./test-TEST.sh $(OPAM_ROOT)/3.12.1/build/P4.3/P4.env "1"
 
 switch:
 	$(MAKE) fresh

tests/compilers/dummy.comp → tests/compilers/3.12.1.comp

@@ -1,5 +1,5 @@
 opam-version: "1"
-name: "test"
+name: "3.12.1"
 preinstalled: true
 env: [
   [ TEST="1" ]

tests/compilers/4.00.0.comp

@@ -0,0 +1,6 @@
+opam-version: "1"
+name: "4.00.0"
+preinstalled: true
+env: [
+  [ TEST="1" ]
+]

tests/packages/P1-2.opam

@@ -2,6 +2,7 @@ opam-version: "1"
 
 package "P1" {
   version:    "2"
+  ocaml-version: [ < "4.00.0" ]
   maintainer: "contact@ocamlpro.com"
   substs:     [ "P1.config" ]
   libraries:  [ "p1" ]