Allow specifying a list of branches to benchmark

This would be useful for benchmarking more than one long running branches of a
repository, for instance, the `5.0` and `trunk` branches of ocaml/ocaml.

pipeline/lib/config.ml

@@ -14,6 +14,7 @@ type repo = {
   build_args : string list; [@default []]
   notify_github : bool; [@default false]
   if_label : string option; [@default None]
+  branches : string list; [@default []]
 }
 [@@deriving yojson]
 
@@ -98,18 +99,32 @@ let default name =
     build_args = [];
     notify_github = false;
     if_label = None;
+    branches = [];
   }
 
-let must_benchmark repo conf =
-  match (conf.if_label, Repository.pull_number repo) with
+let must_benchmark_branch repo conf =
+  match Repository.pull_number repo with
+  | Some _ -> true
+  | _ -> (
+      match (conf.branches, Repository.branch repo) with
+      | (_ :: _ as branches), Some name -> List.mem name branches
+      | [], _ ->
+          Option.value ~default:false @@ Repository.is_default_branch repo
+      | _, _ -> false)
+
+let must_benchmark_pull repo conf =
+  match (conf.if_label, Repository.branch repo) with
   | Some tag, Some _ -> List.mem tag (Repository.labels repo)
   | _ -> true
 
 let find t repo =
   let name = Repository.info repo in
   match List.filter (fun r -> r.name = name) t.repos with
   | [] -> [ default name ]
-  | configs -> List.filter (must_benchmark repo) configs
+  | configs ->
+      configs
+      |> List.filter (must_benchmark_pull repo)
+      |> List.filter (must_benchmark_branch repo)
 
 let find_image t image_name = Images.find image_name t.images
 

pipeline/lib/pipeline.ml

@@ -181,13 +181,15 @@ let github_repositories repo =
         repository ~commit ~github_head:head ~commit_message:message
       in
       match key with
-      (* Skip all branches other than the default branch, and check PRs *)
-      | `Ref branch when branch = default_branch ->
-          repository ~branch:default_branch_name ~labels:[] () :: lst
+      | `Ref branch ->
+          let branch = Util.get_branch_name branch in
+          repository ~branch
+            ~is_default_branch:(branch = default_branch_name)
+            ~labels:[] ()
+          :: lst
       | `PR pr ->
           repository ~title:pr.title ~pull_number:pr.id ~labels:pr.labels ()
-          :: lst
-      | _ -> lst)
+          :: lst)
     ref_map []
 
 let filter_stale_repositories repos =

pipeline/lib/repository.ml

@@ -10,6 +10,7 @@ type t = {
   github_api : Current_github.Api.t option;
   title : string option;
   labels : string list;
+  is_default_branch : bool option;
 }
 
 let default_src ?src commit =
@@ -18,7 +19,7 @@ let default_src ?src commit =
   | Some src -> src
 
 let v ~owner ~name ?src ~commit ?commit_message ?pull_number ?branch
-    ?github_head ?github_api ?title ~labels () =
+    ?github_head ?github_api ?title ~labels ?is_default_branch () =
   {
     owner;
     name;
@@ -31,6 +32,7 @@ let v ~owner ~name ?src ~commit ?commit_message ?pull_number ?branch
     src = default_src ?src commit;
     title;
     labels;
+    is_default_branch;
   }
 
 let owner t = t.owner
@@ -43,6 +45,7 @@ let pull_number t = t.pull_number
 let title t = t.title
 let labels t = t.labels
 let branch t = t.branch
+let is_default_branch t = t.is_default_branch
 let github_head t = t.github_head
 let github_api t = t.github_api
 let id t = (t.owner, t.name)