Add light weight logic to detect newly published packages

The API now makes the flag newly_published a bool option type. When the
flag is None, the library automatically tries to detect if the package
is a newly published one based on whether the repository has any other
versions of the package already in it.

opam-ci-check/bin/main.ml

@@ -67,8 +67,8 @@ let lint (changed_pkgs, new_pkgs) local_repo_dir =
         Lint.v ~pkg ~newly_published ~pkg_src_dir opam
       in
       let all_lint_packages =
-        List.map (process_package ~newly_published:true) new_pkgs
-        @ List.map (process_package ~newly_published:false) changed_pkgs
+        List.map (process_package ~newly_published:(Some true)) new_pkgs
+        @ List.map (process_package ~newly_published:(Some false)) changed_pkgs
       in
       let errors = Lint.lint_packages ~opam_repo_dir all_lint_packages in
       match errors with

opam-ci-check/lib/lint.ml

@@ -371,14 +371,25 @@ end
 
 type t = {
   pkg : OpamPackage.t;
-  newly_published : bool;
+  newly_published : bool option;
   pkg_src_dir : string option;
   opam : OpamFile.OPAM.t;
 }
 
-let v ~pkg ~newly_published ~pkg_src_dir opam =
+let v ~pkg ?(newly_published = None) ~pkg_src_dir opam =
   { pkg; newly_published; pkg_src_dir; opam }
 
+(** A package is considered newly published if the repository doesn't have any
+    other versions of the package, other than the current one.*)
+let is_newly_published ~opam_repo_dir pkg =
+  let pkg_name = OpamPackage.(pkg |> name |> Name.to_string) in
+  let pkg_str = OpamPackage.to_string pkg in
+  match get_files (opam_repo_dir // "packages" // pkg_name) with
+  | exception Sys_error _ -> true
+  | [] -> true
+  | v :: [] when v = pkg_str -> true
+  | _ -> false
+
 let get_package_names repo_dir =
   get_files (repo_dir // "packages") |> List.sort String.compare
 
@@ -387,6 +398,11 @@ 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 } ->
+           let newly_published =
+             match newly_published with
+             | Some v -> v
+             | None -> is_newly_published ~opam_repo_dir pkg
+           in
            Checks.lint_package ~opam_repo_dir ~pkg ~pkg_src_dir
              ~repo_package_names ~newly_published opam)
     |> List.concat |> Result.ok

opam-ci-check/lib/lint.mli

@@ -17,7 +17,7 @@ type t
 
 val v :
   pkg:OpamPackage.t ->
-  newly_published:bool ->
+  ?newly_published:bool option ->
   pkg_src_dir:string option ->
   OpamFile.OPAM.t ->
   t