pkg: fix bug where multiple conflicts causes conlficts to be ignored (#11492)

Conflicts were being combined as a conjunction bet they should have been
combined with a disjunction.

Fixes #11265

Signed-off-by: Stephen Sherratt <[email protected]>

Author: gridbugs

src/dune_pkg/dependency_formula.ml

@@ -2,7 +2,10 @@ open Import
 
 type t = OpamTypes.filtered_formula
 
-let of_dependencies deps = Package_dependency.list_to_opam_filtered_formula deps
+let of_dependencies deps =
+  List.map deps ~f:Package_dependency.to_opam_filtered_formula |> OpamFormula.ands
+;;
+
 let to_filtered_formula v = v
 let of_filtered_formula v = v
 let to_dyn = Opam_dyn.filtered_formula

src/dune_pkg/local_package.ml

@@ -65,11 +65,13 @@ module For_solver = struct
     |> OpamFile.OPAM.with_name (Package_name.to_opam_package_name name)
     |> OpamFile.OPAM.with_depends (Dependency_formula.to_filtered_formula dependencies)
     |> OpamFile.OPAM.with_conflicts
-         (Package_dependency.list_to_opam_filtered_formula conflicts)
+         (List.map conflicts ~f:Package_dependency.to_opam_filtered_formula
+          |> OpamFormula.ors)
     |> OpamFile.OPAM.with_conflict_class
          (List.map conflict_class ~f:Package_name.to_opam_package_name)
     |> OpamFile.OPAM.with_depopts
-         (Package_dependency.list_to_opam_filtered_formula depopts)
+         (List.map depopts ~f:Package_dependency.to_opam_filtered_formula
+          |> OpamFormula.ands)
   ;;
 
   let non_local_dependencies local_deps =

src/dune_pkg/opam_solver.ml

@@ -109,7 +109,9 @@ module Context = struct
       List.map constraints ~f:(fun (constraint_ : Package_dependency.t) ->
         constraint_.name, constraint_)
       |> Package_name.Map.of_list_multi
-      |> Package_name.Map.map ~f:Package_dependency.list_to_opam_filtered_formula
+      |> Package_name.Map.map ~f:(fun formulae ->
+        List.map formulae ~f:Package_dependency.to_opam_filtered_formula
+        |> OpamFormula.ands)
     in
     let available_cache =
       Table.create

src/dune_pkg/package_dependency.ml

@@ -210,16 +210,14 @@ let opam_depend { name; constraint_ } =
   | Some c -> nopos (OpamParserTypes.FullPos.Option (pkg, nopos [ c ]))
 ;;
 
-let list_to_opam_filtered_formula ts =
-  List.map ts ~f:(fun { name; constraint_ } ->
-    let opam_package_name = Package_name.to_opam_package_name name in
-    let condition =
-      match constraint_ with
-      | None -> OpamTypes.Empty
-      | Some constraint_ -> Constraint.to_opam_condition constraint_
-    in
-    OpamFormula.Atom (opam_package_name, condition))
-  |> OpamFormula.ands
+let to_opam_filtered_formula { name; constraint_ } =
+  let opam_package_name = Package_name.to_opam_package_name name in
+  let condition =
+    match constraint_ with
+    | None -> OpamTypes.Empty
+    | Some constraint_ -> Constraint.to_opam_condition constraint_
+  in
+  OpamFormula.Atom (opam_package_name, condition)
 ;;
 
 let list_of_opam_filtered_formula loc kind filtered_formula =

src/dune_pkg/package_dependency.mli

@@ -25,7 +25,7 @@ type t = Dune_lang.Package_dependency.t =
 include module type of Dune_lang.Package_dependency with type t := t
 
 val opam_depend : t -> OpamParserTypes.FullPos.value
-val list_to_opam_filtered_formula : t list -> OpamTypes.filtered_formula
+val to_opam_filtered_formula : t -> OpamTypes.filtered_formula
 
 (** Attempt to interpret a [OpamTypes.filtered_formula] as a list of [t]s by
     treating the formula as a conjunction of packages with constraints. *)

test/blackbox-tests/test-cases/pkg/gh11265.t

@@ -22,7 +22,7 @@ A package which depends on a single package and also conflicts with the same pac
         bar.0.0.1: Package does not satisfy constraints of local package foo
   [1]
 
-Now add an additional conflict on a non-existant package "baz". Dune will choose the package "bar" despite it being a conflict:
+Now add an additional conflict on a non-existant package "baz". Dune should continue to fail to find a solution due to the conflict with "bar".
   $ solve_project << EOF
   > (lang dune 3.11)
   > (package
@@ -31,6 +31,12 @@ Now add an additional conflict on a non-existant package "baz". Dune will choose
   >  (depends bar)
   >  (conflicts bar baz))
   > EOF
-  Solution for dune.lock:
-  - bar.0.0.1
+  Error: Unable to solve dependencies for the following lock directories:
+  Lock directory dune.lock:
+  Couldn't solve the package dependency formula.
+  Selected candidates: foo.dev
+  - bar -> (problem)
+      No usable implementations:
+        bar.0.0.1: Package does not satisfy constraints of local package foo
+  [1]