Fix opam config subst handling of absolute paths

master_changes.md

@@ -39,6 +39,7 @@ users)
 ## Switch
 
 ## Config
+  * Fix `opam config subst` so it works with absolute paths [#6936 @NathanReb]
 
 ## Pin
 
@@ -207,6 +208,8 @@ users)
   * `OpamSolution` remove the heuristic of recomputing depexts of additional (pinned) packages. [#6489 @arozovyk]
   * `OpamClient` update the system package status check for dependencies during `opam install --deps-only`, including support for pinned packages; also update this in `OpamAuxCommands.autopin` [#6489 @arozovyk]
   * `OpamSolution.get_depexts` remove no longer needed `recover` option that was used with `--depext-only` option  [#6489 @arozovyk]
+  * `OpamConfigCommand.subst` now takes a `filename` instead of a `basename`
+    [#???? @NathanReb]
 
 ## opam-repository
   * `OpamRepositoryPath` was moved to `opam-format` [#6917 @rjbou]

src/client/opamCommands.ml

@@ -1479,7 +1479,7 @@ let config cli =
     | Some `subst, (_::_ as files) ->
       OpamGlobalState.with_ `Lock_none @@ fun gt ->
       `Ok (OpamConfigCommand.subst gt
-             (List.map OpamFilename.Base.of_string files))
+             (List.map OpamFilename.of_string files))
     | Some `pef, params ->
       OpamGlobalState.with_ `Lock_none @@ fun gt ->
       OpamSwitchState.with_ `Lock_none gt @@ fun st ->

src/client/opamConfigCommand.ml

@@ -378,11 +378,7 @@ let subst gt fs =
   log "config-substitute";
   OpamSwitchState.with_ `Lock_none gt @@ fun st ->
   let env = OpamPackageVar.resolve st in
-  List.iter
-    (fun b ->
-       let file = OpamFilename.of_basename b in
-       OpamFilter.expand_interpolations_in_file env file)
-    fs
+  List.iter (OpamFilter.expand_interpolations_in_file env) fs
 
 let expand gt str =
   log "config-expand";

src/client/opamConfigCommand.mli

@@ -38,7 +38,7 @@ val print_eval_env: csh:bool -> sexp:bool -> fish:bool -> pwsh:bool -> cmd:bool
 val list: 'a switch_state -> name list -> unit
 
 (** Substitute files *)
-val subst: 'a global_state -> basename list -> unit
+val subst: 'a global_state -> filename list -> unit
 
 (** Prints expansion of variables in string *)
 val expand: 'a global_state -> string -> unit

tests/reftests/config.test

@@ -217,3 +217,16 @@ Done.
 # invariant            ["meta-compiler" "depopt-compiler"]
 # compiler-packages    compiler.1, dep-compiler.1, depopt-compiler.1
 # meta-compiler:compvar something
+### :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+### : opam config subst must accept relative and absolute paths
+### :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
+### <some-dir/relative.in>
+%{root}%
+### <some-dir/absolute.in>
+%{root}%
+### opam config subst some-dir/relative
+### cat some-dir/relative
+${BASEDIR}/OPAM
+### opam config subst $BASEDIR/some-dir/absolute | 'OpamSystem.File_not_found.*' -> 'OpamSystem.File_not_found...'
+### cat some-dir/absolute
+${BASEDIR}/OPAM