Check that opam repository directory is valid

opam-ci-check/bin/main.ml

@@ -72,12 +72,13 @@ let lint (changed_pkgs, new_pkgs) local_repo_dir =
       in
       let errors = Lint.lint_packages ~opam_repo_dir all_lint_packages in
       match errors with
-      | [] ->
+      | Ok [] ->
           print_endline "No errors";
           Ok ()
-      | errors ->
+      | Ok errors ->
           errors |> List.map Lint.msg_of_error |> String.concat "\n"
-          |> Printf.sprintf "%s\n" |> Result.error)
+          |> Printf.sprintf "%s\n" |> Result.error
+      | Error _ as e -> e)
 
 let show_revdeps pkg local_repo_dir no_transitive_revdeps =
   (* Get revdeps for the package *)

opam-ci-check/lib/lint.ml

@@ -383,9 +383,11 @@ let get_package_names repo_dir =
   get_files (repo_dir // "packages") |> List.sort String.compare
 
 let lint_packages ~opam_repo_dir metas =
-  let repo_package_names = get_package_names opam_repo_dir in
-  metas
-  |> List.map (fun { pkg; newly_published; pkg_src_dir; opam } ->
-         Checks.lint_package ~opam_repo_dir ~pkg ~pkg_src_dir
-           ~repo_package_names ~newly_published opam)
-  |> List.concat
+  if Sys.file_exists (opam_repo_dir // "packages") then
+    let repo_package_names = get_package_names opam_repo_dir in
+    metas
+    |> List.map (fun { pkg; newly_published; pkg_src_dir; opam } ->
+           Checks.lint_package ~opam_repo_dir ~pkg ~pkg_src_dir
+             ~repo_package_names ~newly_published opam)
+    |> List.concat |> Result.ok
+  else Error (Printf.sprintf "Invalid opam repository: %s" opam_repo_dir)

opam-ci-check/lib/lint.mli

@@ -31,7 +31,9 @@ val v :
  *)
 
 val lint_packages :
-  opam_repo_dir:string -> t list -> (OpamPackage.t * error) list
+  opam_repo_dir:string ->
+  t list ->
+  ((OpamPackage.t * error) list, string) result
 (** [lint_packages ~opam_repo_dir metas] is a list of all the
     errors detected while linting the packages in the [metas] list in the
     context of the opam repository located at [opam_repo_dir].
@@ -42,9 +44,9 @@ val lint_packages :
 
     {[
 
-      let passes_all_checks = assert (lint_packages ~opam_repo_dir metas |> List.length = 0)
-      let failed_some_checks = assert (lint_packages ~opam_repo_dir metas |> List.length > 0)
+      let passes_all_checks = assert (lint_packages ~opam_repo_dir metas |> Result.get_ok |> List.length = 0)
+      let failed_some_checks = assert (lint_packages ~opam_repo_dir metas |> Result.get_ok |> List.length > 0)
       let messages_for_all_failed_checks =
         lint_packages ~opam_repo_dir ~repo_packages metas
-        |> List.map msg_of_error
+        |> Result.get_ok |> List.map msg_of_error
     ]} *)