Check for maintainer emails in the opam file

This commit adds a simple regex search for emails in the maintainer
field. Closes #20

lib/dune

@@ -1,4 +1,4 @@
 (library
  (name opam_ci_check)
  (public_name opam-ci-check)
- (libraries opam-client sexplib mula))
+ (libraries opam-client sexplib mula str))

lib/lint.ml

@@ -260,6 +260,14 @@ module Checks = struct
         if is_build then [ (pkg, DuneIsBuild) ] else errors
     | None -> []
 
+  let check_maintainer_email ~pkg opam =
+    let maintainers = OpamFile.OPAM.maintainer opam in
+    List.filter_map
+      (fun m ->
+        if Str.string_match (Str.regexp ".*<?.*@.*>?") m 0 then None
+        else Some (pkg, MaintainerEmailMissing m))
+      maintainers
+
   let opam_lint ~pkg opam =
     OpamFileTools.lint ~check_upstream:true opam
     |> List.map (fun x -> (pkg, OpamLint x))
@@ -343,6 +351,7 @@ module Checks = struct
         check_checksums;
         check_package_dir ~repo_dir;
         opam_lint;
+        check_maintainer_email;
         check_no_pin_depends;
         check_no_extra_files;
         Prefix.check_prefix_conflict_class_mismatch;

lib/lint_error.ml

@@ -21,6 +21,7 @@ type error =
   | UnexpectedFile of string
   | ForbiddenPerm of string
   | OpamLint of (int * [ `Warning | `Error ] * string)
+  | MaintainerEmailMissing of string
   | FailedToDownload of string
   | NameCollision of string
   | WeakChecksum of string
@@ -137,5 +138,10 @@ let msg_of_error (package, (err : error)) =
   | OpamLint warn ->
       let warn = OpamFileTools.warns_to_string [ warn ] in
       Printf.sprintf "Error in %s: %s" pkg warn
+  | MaintainerEmailMissing maintainer ->
+      Printf.sprintf
+        "Error in %s: Maintainer email missing. Please add a maintainer email \
+         to the opam file. Maintainer: %s"
+        pkg maintainer
   | ParseError ->
       Printf.sprintf "Error in %s: Failed to parse the opam file" pkg

test/lint.t

@@ -43,6 +43,7 @@ Setup repo for incorrect b package tests
 
 Test the following:
 - [b.0.0.1] is missing the [author] field
+- [b.0.0.1] is missing the maintainer's email in the [maintainer] field
 - [b.0.0.2] has an extra unknown field
 - [b.0.0.3] has a pin-depends present, and a conflict class without the required prefix; use of extra-files and a weak checksum algorithm
 - [system-b.0.0.1] is using a restricted prefix in its name
@@ -54,6 +55,7 @@ Test the following:
   $ opam-ci-check lint -r . -c b.0.0.1
   Linting opam-repository at $TESTCASE_ROOT/. ...
   Error in b.0.0.1:            warning 25: Missing field 'authors'
+  Error in b.0.0.1: Maintainer email missing. Please add a maintainer email to the opam file. Maintainer: Jane
   [1]
   $ opam-ci-check lint -r . -c b.0.0.2
   Linting opam-repository at $TESTCASE_ROOT/. ...

test/patches/a-1.patch

@@ -19,7 +19,7 @@ index 0000000..58229e8
 +opam-version: "2.0"
 +synopsis: "Synopsis"
 +description: "Description"
-+maintainer: "Maintainer"
++maintainer: "Maintainer <[email protected]>"
 +author: "Author"
 +license: "Apache-2.0"
 +homepage: "https://github.com/ocurrent/opam-repo-ci"
@@ -37,7 +37,7 @@ index 0000000..58229e8
 +opam-version: "2.0"
 +synopsis: "Synopsis"
 +description: "Description"
-+maintainer: "Maintainer"
++maintainer: "Maintainer <[email protected]>"
 +author: "Author"
 +license: "Apache-2.0"
 +homepage: "https://github.com/ocurrent/opam-repo-ci"

test/patches/a_1-name-collision.patch

@@ -17,7 +17,7 @@ index 0000000..58229e8
 +opam-version: "2.0"
 +synopsis: "Synopsis"
 +description: "Description"
-+maintainer: "Maintainer"
++maintainer: "Maintainer <[email protected]>"
 +author: "Author"
 +license: "Apache-2.0"
 +homepage: "https://github.com/ocurrent/opam-repo-ci"

test/patches/b-correct.patch

@@ -21,7 +21,7 @@ index 0000000..69040f4
 +opam-version: "2.0"
 +synopsis: "Synopsis"
 +description: "Description"
-+maintainer: "Maintainer"
++maintainer: "Maintainer <[email protected]>"
 +author: "Author"
 +license: "Apache-2.0"
 +homepage: "https://github.com/ocurrent/opam-repo-ci"
@@ -41,7 +41,7 @@ index 0000000..1581508
 +opam-version: "2.0"
 +synopsis: "Synopsis"
 +description: "Description"
-+maintainer: "Maintainer"
++maintainer: "Maintainer <[email protected]>"
 +author: "Author"
 +license: "Apache-2.0"
 +homepage: "https://github.com/ocurrent/opam-repo-ci"
@@ -61,7 +61,7 @@ index 0000000..5ec1dc4
 +opam-version: "2.0"
 +synopsis: "Synopsis"
 +description: "Description"
-+maintainer: "Maintainer"
++maintainer: "Maintainer <[email protected]>"
 +author: "Author"
 +license: "Apache-2.0"
 +homepage: "https://github.com/ocurrent/opam-repo-ci"

test/patches/b-incorrect-opam.patch

@@ -7,7 +7,7 @@ index 0000000..3697498
 +opam-version: "2.0"
 +synopsis: "Synopsis"
 +description: "Description"
-+maintainer: "Maintainer"
++maintainer: "Jane"
 +license: "Apache-2.0"
 +homepage: "https://github.com/ocurrent/opam-repo-ci"
 +bug-reports: "https://github.com/ocurrent/opam-repo-ci/issues"
@@ -26,7 +26,7 @@ index 0000000..a47aabf
 +opam-version: "2.0"
 +synopsis: "Synopsis"
 +description: "Description"
-+maintainer: "Maintainer"
++maintainer: "Maintainer <[email protected]>"
 +author: "Author"
 +license: "Apache-2.0"
 +homepage: "https://github.com/ocurrent/opam-repo-ci"
@@ -54,7 +54,7 @@ index 0000000..5bab63e
 +opam-version: "2.0"
 +synopsis: "Synopsis"
 +description: "Description"
-+maintainer: "Maintainer"
++maintainer: "Maintainer <[email protected]>"
 +author: "Author"
 +license: "Apache-2.0"
 +homepage: "https://github.com/ocurrent/opam-repo-ci"
@@ -84,7 +84,7 @@ index 0000000..0808e56
 +opam-version: "2.0"
 +synopsis: "Synopsis"
 +description: "Description"
-+maintainer: "Maintainer"
++maintainer: "Maintainer <[email protected]>"
 +author: "Author"
 +license: "Apache-2.0"
 +homepage: "https://github.com/ocurrent/opam-repo-ci"
@@ -104,7 +104,7 @@ index 0000000..5bab63e
 +opam-version: "2.0"
 +synopsis: "Synopsis"
 +description: "Description"
-+maintainer: "Maintainer"
++maintainer: "Maintainer <[email protected]>"
 +author: "Author"
 +license: "Apache-2.0"
 +homepage: "https://github.com/ocurrent/opam-repo-ci"
@@ -129,7 +129,7 @@ index 0000000..5bab63e
 +opam-version: "2.0"
 +synopsis: "Synopsis"
 +description: "Description"
-+maintainer: "Maintainer"
++maintainer: "Maintainer <[email protected]>"
 +author: "Author"
 +license: "Apache-2.0"
 +homepage: "https://github.com/ocurrent/opam-repo-ci"
@@ -153,7 +153,7 @@ index 0000000..5bab63e
 +opam-version: "2.0"
 +synopsis: "Synopsis"
 +description: "Description"
-+maintainer: "Maintainer"
++maintainer: "Maintainer <[email protected]>"
 +author: "Author"
 +license: "Apache-2.0"
 +homepage: "https://github.com/ocurrent/opam-repo-ci"

test/patches/levenshtein-2.patch

@@ -7,7 +7,7 @@ index 0000000..5246a83
 +opam-version: "2.0"
 +synopsis: "Synopsis"
 +description: "Description"
-+maintainer: "Maintainer"
++maintainer: "Maintainer <[email protected]>"
 +author: "Author"
 +license: "Apache-2.0"
 +homepage: "https://github.com/ocurrent/opam-repo-ci"
@@ -25,7 +25,7 @@ index 0000000..5246a83
 +opam-version: "2.0"
 +synopsis: "Synopsis"
 +description: "Description"
-+maintainer: "Maintainer"
++maintainer: "Maintainer <[email protected]>"
 +author: "Author"
 +license: "Apache-2.0"
 +homepage: "https://github.com/ocurrent/opam-repo-ci"
@@ -43,7 +43,7 @@ index 0000000..5246a83
 +opam-version: "2.0"
 +synopsis: "Synopsis"
 +description: "Description"
-+maintainer: "Maintainer"
++maintainer: "Maintainer <[email protected]>"
 +author: "Author"
 +license: "Apache-2.0"
 +homepage: "https://github.com/ocurrent/opam-repo-ci"
@@ -61,7 +61,7 @@ index 0000000..5246a83
 +opam-version: "2.0"
 +synopsis: "Synopsis"
 +description: "Description"
-+maintainer: "Maintainer"
++maintainer: "Maintainer <[email protected]>"
 +author: "Author"
 +license: "Apache-2.0"
 +homepage: "https://github.com/ocurrent/opam-repo-ci"