track opam file metadata in dune-project and rewrite opam files

CHANGES.md

@@ -25,6 +25,10 @@ unreleased
   to produce targets that are present in the source tree. This has
   been a warning for long enough (#2068, @diml)
 
+- Add more opam metadata and use it to generate corrections to the .opam files
+  in the source. This allows the user to partially specify opam metadata in the
+  the dune-project file. (#2017, @avsm, @jonludlam)
+
 1.9.1 (11/04/2019)
 ------------------
 

doc/index.rst

@@ -22,6 +22,7 @@ Welcome to dune's documentation!
    configurator
    menhir
    jsoo
+   opam
    variants
    formatting
    coq

doc/opam.rst

@@ -0,0 +1,103 @@
+****
+opam
+****
+
+opam_ is the official package manager for OCaml, and dune offers some
+integration with it.
+
+Generating opam files
+=====================
+
+Dune is able to use metadata specified in the ``dune-project`` file to cross
+reference it with the information in the user written ``.opam`` file. To enable
+this integration, a user needs to add an ``(opam ..)`` field to the dune-project
+file.
+
+The fields that dune uses for this purpose are:
+
+- ``(license <name>)`` - Specified the license of the project
+
+- ``(authors <authors>)`` - A list of authors
+
+- ``(source <source>)`` - where the source is specified two ways:
+  ``(github <user/repo>)`` or ``(uri <uri>)``
+
+To enable dune suggesting corrections to the opam stanza, the user must specify
+an ``(opam <fields>)`` with the fields:
+
+- ``(tags <tags>)`` - Specify the list of tags for all packages
+- ``(depends <dep-specification>)`` - The list of dependencies shared by all opam packages
+  in this dune project
+- ``(conflicts <dep-specification>)`` - The list of conflicts shared by all opam
+  packages in this dune project
+- ``(package <package>)`` - the list of packages in this project and their
+  individual metadata.
+
+The list of dependencies ``<dep-specification>`` is modeled after opam's own
+language: The syntax is as a list of the following elements:
+
+.. code::
+   op := '=' | '<' | '>' | '<>' | '>=' | '<='
+
+   stage := :with_test | :build | :dev
+
+   constr := (<op> <version>)
+
+   logop := or | and
+
+   dep := (name <stage>)
+        | (name <constr>)
+        | (name (<logop> (<stage> | <constr>)*))
+
+   dep-specification = dep+
+
+The `(package <package>)` field contains the fields:
+
+- ``(name <string>)`` is the name of the package
+
+- ``(synopsis <string>)`` is a short package description
+
+- ``(description <string>)`` is a longer package description
+
+- ``(depends <dep-specification>)`` are package specific dependencies
+
+- ``(conflicts <dep-specification)`` are package specific conflicts
+
+Here's a complete example of a dune file with opam metadata specification:
+
+.. code:: scheme
+
+   (lang dune 1.10)
+   (name cohttp)
+   (source (github mirage/ocaml-cohttp))
+   (license ISC)
+   (authors "Anil Madhavapeddy" "Rudi Grinberg")
+
+   (opam
+     (tags org:mirage org:dune)
+     (depends
+     (ocaml (>= 4.06.0))
+     (cohttp (>= 1.0.0)))
+     (package
+       (name cohttp)
+       (synopsis "An OCaml library for HTTP clients and servers")
+       (description "A longer description")
+       (depends
+         (alcotest :with-test)
+         (dune (and :build (> 1.5)))
+         (foo (and :dev (> 1.5) (< 2.0)))
+         (uri (>= 1.9.0))
+         (uri (< 2.0.0))
+         (fieldslib (> v0.12))
+         (fieldslib (< v0.13))))
+     (package
+       (name cohttp-async)
+       (synopsis "HTTP client and server for the Async library")
+       (description "A _really_ long description")
+       (depends
+         (cohttp (>= 1.0.2))
+         (conduit-async (>= 1.0.3))
+         (async (>= v0.10.0))
+         (async (< v0.12)))))
+
+.. _opam: https://opam.ocaml.org/

dune-project

@@ -1,4 +1,38 @@
-(lang dune 1.8)
+(lang dune 1.10)
 (name dune)
 
-(implicit_transitive_deps false)
+(implicit_transitive_deps false)
+
+(license MIT)
+(authors "Jane Street Group, LLC <opensource@janestreet.com>")
+(source (github ocaml/dune))
+
+(opam
+ (package
+  (name dune)
+  (depends
+   (ocaml (>= 4.02))
+   base-unix
+   base-threads)
+  (conflicts
+   (jbuilder (<> "transition"))
+   (odoc (< 1.3.0)))
+  (synopsis "Fast, portable and opinionated build system")
+  (description "
+dune is a build system that was designed to simplify the release of
+Jane Street packages. It reads metadata from \"dune\" files following a
+very simple s-expression syntax.
+
+dune is fast, it has very low-overhead and support parallel builds on
+all platforms. It has no system dependencies, all you need to build
+dune and packages using dune is OCaml. You don't need or make or bash
+as long as the packages themselves don't use bash explicitly.
+
+dune supports multi-package development by simply dropping multiple
+repositories into the same directory.
+
+It also supports multi-context builds, such as building against
+several opam roots/switches simultaneously. This helps maintaining
+packages across several versions of OCaml and gives cross-compilation
+for free.
+")))

dune.opam

@@ -21,7 +21,6 @@ conflicts: [
   "jbuilder" {!= "transition"}
   "odoc" {< "1.3.0"}
 ]
-
 synopsis: "Fast, portable and opinionated build system"
 description: """
 dune is a build system that was designed to simplify the release of

example/sample-projects/hello_world/hello_world.opam

@@ -8,4 +8,4 @@ dev-repo: "git+https://github.com/SpongeBob/hello_world.git"
 license: "Apache-2.0"
 build: [
   ["dune" "build" "-p" name "-j" jobs]
-]
+]

example/sample-projects/with-configure-step/myproject.opam

@@ -8,4 +8,4 @@ dev-repo: "git+https://github.com/SpongeBob/myproject.git"
 license: "Apache-2.0"
 build: [
   ["dune" "build" "-p" name "-j" jobs]
-]
+]

src/blang.ml

@@ -15,6 +15,16 @@ module Op = struct
     | (Neq | Lt  | Lte) , Lt
     | (Neq | Gt  | Gte) , Gt -> true
     | _, _ -> false
+
+  let to_dyn =
+    let open Dyn.Encoder in
+    function
+    | Eq -> string "Eq"
+    | Gt -> string "Gt"
+    | Gte -> string "Gte"
+    | Lte -> string "Lte"
+    | Lt -> string "Lt"
+    | Neq -> string "Neq"
 end
 
 type t =
@@ -43,3 +53,52 @@ let rec eval t ~dir ~f =
     let x = String_with_vars.expand x ~mode:Many ~dir ~f
     and y = String_with_vars.expand y ~mode:Many ~dir ~f in
     Op.eval op (Value.L.compare_vals ~dir x y)
+
+let rec to_dyn =
+  let open Dyn.Encoder in
+  function
+  | Const b -> constr "Const" [bool b]
+  | Expr e -> constr "Expr" [via_sexp String_with_vars.to_sexp e]
+  | And t -> constr "And" (List.map ~f:to_dyn t)
+  | Or t -> constr "Or" (List.map ~f:to_dyn t)
+  | Compare (o, s1, s2) ->
+    constr "Compare"
+      [ Op.to_dyn o
+      ; via_sexp String_with_vars.to_sexp s1
+      ; via_sexp String_with_vars.to_sexp s2
+      ]
+
+let ops =
+  [ "=", Op.Eq
+  ; ">=", Gte
+  ; "<=", Lt
+  ; ">", Gt
+  ; "<", Lt
+  ; "<>", Neq
+  ]
+
+let decode =
+  let open Stanza.Decoder in
+  let ops =
+    List.map ops ~f:(fun (name, op) ->
+      ( name
+      , (let+ x = String_with_vars.decode
+         and+ y = String_with_vars.decode
+         in
+         Compare (op, x, y))))
+  in
+  let decode =
+    fix begin fun t ->
+      if_list
+        ~then_:(
+          [ "or", repeat t >>| (fun x -> Or x)
+          ; "and", repeat t >>| (fun x -> And x)
+          ] @ ops
+          |> sum)
+        ~else_:(String_with_vars.decode >>| fun v -> Expr v)
+    end
+  in
+  let+ () = Syntax.since Stanza.syntax (1, 1)
+  and+ decode = decode
+  in
+  decode

src/blang.mli

@@ -22,5 +22,9 @@ val true_ : t
 val eval
   :  t
   -> dir:Path.t
-  -> f:Value.t list option  String_with_vars.expander
+  -> f:Value.t list option String_with_vars.expander
   -> bool
+
+val to_dyn : t -> Dyn.t
+
+val decode : t Stanza.Decoder.t

src/dune_file.ml

@@ -319,43 +319,6 @@ module Preprocess = struct
               ]))
 end
 
-module Blang = struct
-  include Blang
-
-  let ops =
-    [ "=", Op.Eq
-    ; ">=", Gte
-    ; "<=", Lt
-    ; ">", Gt
-    ; "<", Lt
-    ; "<>", Neq
-    ]
-
-  let decode =
-    let ops =
-      List.map ops ~f:(fun (name, op) ->
-        ( name
-        , (let+ x = String_with_vars.decode
-           and+ y = String_with_vars.decode
-           in
-           Compare (op, x, y))))
-    in
-    let decode =
-      fix begin fun t ->
-        if_list
-          ~then_:(
-            [ "or", repeat t >>| (fun x -> Or x)
-            ; "and", repeat t >>| (fun x -> And x)
-            ] @ ops
-            |> sum)
-          ~else_:(String_with_vars.decode >>| fun v -> Expr v)
-      end
-    in
-    let+ () = Syntax.since Stanza.syntax (1, 1)
-    and+ decode = decode
-    in
-    decode
-end
 
 let enabled_if =
   field "enabled_if" ~default:Blang.true_