Check that default, example tags have been removed

lib/lint.ml

@@ -268,6 +268,21 @@ module Checks = struct
         else Some (pkg, MaintainerEmailMissing m))
       maintainers
 
+  let check_tags ~pkg opam =
+    (* Check if any of the default tags are present *)
+    let tags = OpamFile.OPAM.tags opam in
+    let default_tags =
+      [ "add topics"; "topics"; "to describe"; "your"; "project" ]
+    in
+    let default_tags_present =
+      List.filter_map
+        (fun tag -> if List.mem tag tags then Some tag else None)
+        default_tags
+    in
+    match default_tags_present with
+    | [] -> []
+    | _ -> [ (pkg, DefaultTagsPresent default_tags_present) ]
+
   let opam_lint ~pkg opam =
     OpamFileTools.lint ~check_upstream:true opam
     |> List.map (fun x -> (pkg, OpamLint x))
@@ -352,6 +367,7 @@ module Checks = struct
         check_package_dir ~repo_dir;
         opam_lint;
         check_maintainer_email;
+        check_tags;
         check_no_pin_depends;
         check_no_extra_files;
         Prefix.check_prefix_conflict_class_mismatch;

lib/lint_error.ml

@@ -30,6 +30,7 @@ type error =
   | RestrictedPrefix of string
   | PrefixConflictClassMismatch of prefix_conflict_class_mismatch
   | ParseError
+  | DefaultTagsPresent of string list
 
 (**/**)
 
@@ -145,3 +146,8 @@ let msg_of_error (package, (err : error)) =
         pkg maintainer
   | ParseError ->
       Printf.sprintf "Error in %s: Failed to parse the opam file" pkg
+  | DefaultTagsPresent tags ->
+      Printf.sprintf
+        "Warning in %s: The package has not replaced the following default, \
+         example tags: %s"
+        pkg (String.concat ", " tags)

test/lint.t

@@ -44,6 +44,7 @@ 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.0.0.1] has default, example tags
 - [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
@@ -56,6 +57,7 @@ Test the following:
   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
+  Warning in b.0.0.1: The package has not replaced the following default, example tags: topics, project
   [1]
   $ opam-ci-check lint -r . -c b.0.0.2
   Linting opam-repository at $TESTCASE_ROOT/. ...

test/patches/b-incorrect-opam.patch

@@ -3,7 +3,7 @@ new file mode 100644
 index 0000000..3697498
 --- /dev/null
 +++ b/packages/b/b.0.0.1/opam
-@@ -0,0 +1,13 @@
+@@ -0,0 +1,14 @@
 +opam-version: "2.0"
 +synopsis: "Synopsis"
 +description: "Description"
@@ -13,6 +13,7 @@ index 0000000..3697498
 +bug-reports: "https://github.com/ocurrent/opam-repo-ci/issues"
 +dev-repo: "git+https://github.com/ocurrent/opam-repo-ci.git"
 +doc: "https://ocurrent.github.io/ocurrent/"
++tags: ["topics" "sample" "project"]
 +build: []
 +depends: [
 +  "a-1" {>= "0.0.1"}