From 764f2820fe3c6809bb05ad951a5e2086296eae50 Mon Sep 17 00:00:00 2001
From: Kate <kit-ty-kate@outlook.com>
Date: Tue, 18 Jun 2024 12:01:29 +0100
Subject: [PATCH] Nullify positions of the extensions fields in
 OpamFile.OPAM.effective_part

---
 master_changes.md                     |  2 ++
 src/format/opamFile.ml                |  5 ++-
 src/format/opamTypesBase.ml           | 50 +++++++++++++++++++++++++++
 src/format/opamTypesBase.mli          |  2 ++
 tests/reftests/effectively-equal.test |  5 ++-
 5 files changed, 60 insertions(+), 4 deletions(-)

diff --git a/master_changes.md b/master_changes.md
index ced8e49a992..e1352844fb6 100644
--- a/master_changes.md
+++ b/master_changes.md
@@ -40,6 +40,7 @@ users)
 ## Var/Option
 
 ## Update / Upgrade
+  * Fix `opam upgrade` wanting to recompile opam files containing the `x-env-path-rewrite` field [#6029 @kit-ty-kate - fix #6028]
 
 ## Tree
 
@@ -119,5 +120,6 @@ users)
 ## opam-solver
 
 ## opam-format
+  * `OpamTypesBase`: Add `nullify_pos_map` and `nullify_pos_value` [#6029 @kit-ty-kate]
 
 ## opam-core
diff --git a/src/format/opamFile.ml b/src/format/opamFile.ml
index 0c0f53b16a9..87e719e1716 100644
--- a/src/format/opamFile.ml
+++ b/src/format/opamFile.ml
@@ -3629,7 +3629,10 @@ module OPAM = struct
 
       (* We keep only `x-env-path-rewrite` as it affects build/install *)
       extensions  =
-        OpamStd.String.Map.filter (fun x _ -> String.equal rewrite_xfield x)
+        OpamStd.String.Map.filter_map (fun k v ->
+            if String.equal rewrite_xfield k
+            then Some (OpamTypesBase.nullify_pos_value v)
+            else None)
           t.extensions;
 
       url         = OpamStd.Option.map effective_url t.url;
diff --git a/src/format/opamTypesBase.ml b/src/format/opamTypesBase.ml
index eb016bc0bb1..e8f252fdf2d 100644
--- a/src/format/opamTypesBase.ml
+++ b/src/format/opamTypesBase.ml
@@ -62,6 +62,56 @@ let pos_null =
     stop = -1, -1;
   }
 let nullify_pos pelem = {pelem; pos = pos_null}
+let nullify_pos_map f {pelem; pos = _} = nullify_pos (f pelem)
+
+let rec nullify_pos_value {pelem; pos = _} =
+  nullify_pos @@
+  match pelem with
+  | Bool b -> Bool (b : bool)
+  | Int i -> Int (i : int)
+  | String s -> String (s : string)
+  | Relop (relop, v1, v2) ->
+    Relop
+      (nullify_pos_map
+         (fun (x : OpamParserTypes.FullPos.relop_kind) -> x)
+         relop,
+       nullify_pos_value v1,
+       nullify_pos_value v2)
+  | Prefix_relop (relop, v) ->
+    Prefix_relop
+      (nullify_pos_map
+         (fun (x : OpamParserTypes.FullPos.relop_kind) -> x)
+         relop,
+       nullify_pos_value v)
+  | Logop (logop, v1, v2) ->
+    Logop
+      (nullify_pos_map
+         (fun (x : OpamParserTypes.FullPos.logop_kind) -> x)
+         logop,
+       nullify_pos_value v1,
+       nullify_pos_value v2)
+  | Pfxop (pfxop, v) ->
+    Pfxop
+      (nullify_pos_map
+         (fun (x : OpamParserTypes.FullPos.pfxop_kind) -> x)
+         pfxop,
+       nullify_pos_value v)
+  | Ident s -> Ident (s : string)
+  | List {pelem = l; pos = _} ->
+    List (nullify_pos (List.map nullify_pos_value l))
+  | Group {pelem = l; pos = _} ->
+    Group (nullify_pos (List.map nullify_pos_value l))
+  | Option (v, {pelem = filter; pos = _}) ->
+    Option
+      (nullify_pos_value v,
+       nullify_pos (List.map nullify_pos_value filter))
+  | Env_binding (v1, env_update_op, v2) ->
+    Env_binding
+      (nullify_pos_value v1,
+       nullify_pos_map
+         (fun (x : OpamParserTypes.FullPos.env_update_op_kind) -> x)
+         env_update_op,
+       nullify_pos_value v2)
 
 (* XXX update *)
 let pos_best pos1 pos2 =
diff --git a/src/format/opamTypesBase.mli b/src/format/opamTypesBase.mli
index 8ba6da9f23d..11b5478c58b 100644
--- a/src/format/opamTypesBase.mli
+++ b/src/format/opamTypesBase.mli
@@ -42,6 +42,8 @@ val string_of_shell: shell -> string
 (** The empty file position *)
 val pos_null: pos
 val nullify_pos : 'a -> 'a with_pos
+val nullify_pos_map : ('a -> 'b) -> 'a with_pos -> 'b with_pos
+val nullify_pos_value : value -> value
 
 (** [pos_best pos1 pos2] returns the most detailed position between [pos1] and
     [pos2] (defaulting to [pos1]) *)
diff --git a/tests/reftests/effectively-equal.test b/tests/reftests/effectively-equal.test
index 765a58f1937..80743d62aca 100644
--- a/tests/reftests/effectively-equal.test
+++ b/tests/reftests/effectively-equal.test
@@ -222,6 +222,5 @@ Already up-to-date.
 Nothing to do.
 ### rm OPAM/eff-eq/.opam-switch/packages/cache
 ### opam upgrade --show
-The following actions would be performed:
-=== recompile 1 package
-  - recompile test-all-fields 1 [upstream or system changes]
+Already up-to-date.
+Nothing to do.