Allow post-install-commands hooks to modify/remove installed files

doc/pages/Manual.md

@@ -1378,7 +1378,8 @@ them modified with [`opam option --global`](man/opam-option.html).
     modified during the installation of the package.
     Note that this hook is run after the scan for installed files is
     done, so any additional installed files won't be recorded and must be taken
-    care of by a `pre-remove-commands` hook.
+    care of by a `pre-remove-commands` hook. However, modified or deleted installed
+    files during the `post-install-commands` will be handled correctly by `opam`.
 - <a id="configfield-pre-session-commands">`pre-session-commands: [ [ <term> { <filter> } ... ] { <filter> } ... ]`</a>,
   <a id="configfield-post-session-commands">`post-session-commands: [ [ <term> { <filter> } ... ] { <filter> } ... ]`</a>:
   These commands will be run once respectively before and after the sequence of

master_changes.md

@@ -17,6 +17,7 @@ New option/command/subcommand are prefixed with ◈.
 
 ## Install
   * The stdout of `pre-` and `post-session` hooks is now propagated to the user [#4382 @AltGr - fix #4359]
+  * `post-install` hooks are allowed to modify or remove installed files, the but not add new ones. Those changes are integrated in changes file [#4388 @lefessan]
 
 ## Remove
   *

src/client/opamAction.ml

@@ -869,6 +869,8 @@ let install_package t ?(test=false) ?(doc=false) ?build_dir nv =
     | Some e -> Some e
     | None -> try process_dot_install t nv dir; None with e -> Some e
   in
+  let root = t.switch_global.root in
+  let switch_prefix = OpamPath.Switch.root root t.switch in
   let post_install error changes =
     let local =
       let added =
@@ -885,17 +887,25 @@ let install_package t ?(test=false) ?(doc=false) ?build_dir nv =
         (OpamVariable.of_string "installed-files")
         (Some (L added))
     in
+    let hooks =
+      get_wrapper t opam wrappers ~local OpamFile.Wrappers.post_install
+    in
+    let has_hooks = match hooks with [] -> false | _ -> true in
     OpamProcess.Job.of_fun_list ~keep_going:true
-      (List.map (fun cmd () -> mk_cmd cmd)
-         (get_wrapper t opam wrappers ~local OpamFile.Wrappers.post_install))
+      (List.map (fun cmd () -> mk_cmd cmd) hooks)
     @@+ fun error_post ->
     match error, error_post with
     | Some err, _ -> Done (Some err, changes)
     | None, Some (_cmd, r) -> Done (Some (OpamSystem.Process_error r), changes)
-    | None, None -> Done (None, changes)
+    | None, None ->
+      let changes =
+        if has_hooks then
+          OpamDirTrack.update switch_prefix changes
+        else
+          changes
+      in
+      Done (None, changes)
   in
-  let root = t.switch_global.root in
-  let switch_prefix = OpamPath.Switch.root root t.switch in
   let rel_meta_dir =
     OpamFilename.(Base.of_string (remove_prefix_dir switch_prefix
                                     (OpamPath.Switch.meta root t.switch)))

src/core/opamDirTrack.ml

@@ -268,3 +268,33 @@ let revert ?title ?(verbose=OpamConsole.verbose()) ?(force=false)
                     (OpamStd.Option.to_string (fun pr ->
                          if pr then "[hash] " else "[tms] ") pre) ^ x) lf))
           cannot))
+
+let update prefix t =
+  let removed = ref [] in
+  let prefix = OpamFilename.Dir.to_string prefix in
+  let update_digest file digest =
+    match
+      let filename = Filename.concat prefix file in
+      let precise = is_precise_digest digest in
+      item_digest ( item_of_filename ~precise filename )
+    with
+    | exception Unix.Unix_error ( ENOENT, _, _) ->
+      removed := file :: !removed;
+      digest
+    | exception _exn -> digest
+    | digest -> digest
+  in
+  let t =
+    SM.mapi (fun file change ->
+        match change with
+        | Added digest -> Added (update_digest file digest)
+        | Removed -> Removed
+        | Contents_changed digest ->
+          Contents_changed (update_digest file digest)
+        | Perm_changed digest -> Perm_changed (update_digest file digest)
+        | Kind_changed digest -> Kind_changed (update_digest file digest)
+      ) t
+  in
+  List.fold_left (fun t file ->
+      SM.remove file t
+    ) t !removed

src/core/opamDirTrack.mli

@@ -54,3 +54,7 @@ val revert:
 val check:
   OpamFilename.Dir.t -> t ->
   (OpamFilename.t * [`Unchanged | `Removed | `Changed]) list
+
+(** Reload all the digests from the directory [prefix]. Remove a file
+    from the map if it has been removed from the file-system. *)
+val update : OpamFilename.Dir.t -> t -> t