Save disk space by only caching dev packages into the internal 'sources' directory

master_changes.md

@@ -31,6 +31,7 @@ users)
 
 ## Actions
   * Reorder the list of actions by increased priority [#6864 @kit-ty-kate - fix #6863]
+  * The internal `sources` directory now only serves to cache dev packages instead of every packages, saving disk space. For other packages it is now removed during the build phase. [#6440 @kit-ty-kate - fix #4056 #5448]
 
 ## Install
   * Remove the build directory as soon as possible when installing a package [#6906 @kit-ty-kate - fix #5884]
@@ -332,6 +333,7 @@ users)
   * `OpamSysInteract`: add `available_packages` and `installed_packages` to be computed separately, redefine `packages_status` accordingly. These funct-ions are now no-op if the given system packages set is empty.  [#6489 @arozovyk]
   * `OpamGlobalState`: add `is_root_read_only` to check if we are in sandboxed environment [#6489 @rjbou]
   * `OpamSwitchState`: add `update_sys_packages` to update depexts status of a set of packages. [#6489 @arozovyk]
+  * `OpamSwitchState`: add `is_source_dir_temporary` [#6440 @kit-ty-kate]
   * `OpamSysInteract`: add `available_packages` and `installed_packages` to be computed separately, redefine `packages_status` accordingly [#6489 @arozovyk]
   * `OpamStateTypes`: add available system package status field `repos_syspkgs_available` (and its type `repo_syspkgs_available`) in `repos_state` for all the depexts declared in repo's packages. The new field is also added to the cache. [#6489 @arozovyk @rjbou]
   * `OpamRepositoryState.load`: load repo's available system packages [#6489 @arozovyk]

src/client/opamSolution.ml

@@ -661,8 +661,12 @@ let parallel_apply t
       in
       let source_dir = source_dir nv in
       (if OpamFilename.exists_dir source_dir
-       then (if not is_inplace then
-               OpamFilename.copy_dir ~src:source_dir ~dst:build_dir)
+       then
+         (if not is_inplace then
+            (if OpamSwitchState.is_source_dir_temporary t nv then
+               OpamFilename.move_dir ~src:source_dir ~dst:build_dir
+             else
+               OpamFilename.copy_dir ~src:source_dir ~dst:build_dir))
        else OpamFilename.mkdir build_dir;
        OpamAction.prepare_package_source t nv build_dir @@+ function
        | Some exn -> store_time (); Done (`Exception exn)
@@ -702,7 +706,11 @@ let parallel_apply t
          OpamFilename.rmdir d;
          let source_dir = source_dir nv in
          if OpamFilename.exists_dir source_dir
-         then OpamFilename.copy_dir ~src:source_dir ~dst:d
+         then
+           (if OpamSwitchState.is_source_dir_temporary t nv then
+              OpamFilename.move_dir ~src:source_dir ~dst:d
+            else
+              OpamFilename.copy_dir ~src:source_dir ~dst:d)
          else OpamFilename.mkdir d;
          OpamAction.prepare_package_source t nv d
        else Done None) @@+ fun _ ->

src/state/opamSwitchState.ml

@@ -808,6 +808,9 @@ let source_dir st nv =
   then OpamPath.Switch.pinned_package st.switch_global.root st.switch nv.name
   else OpamPath.Switch.sources st.switch_global.root st.switch nv
 
+let is_source_dir_temporary st nv =
+  not (OpamPackage.Set.mem nv st.pinned || is_dev_package st nv)
+
 let overlay_opam_file st name =
   if is_pinned st name then
     let file =

src/state/opamSwitchState.mli

@@ -152,9 +152,15 @@ val dev_packages: 'a switch_state -> package_set
 
 (** Returns the local source mirror for the given package
     ({!OpamPath.Switch.sources} or {!OpamPath.Switch.pinned_package}, depending
-    on wether it's pinned). *)
+    on whether it's pinned. If it's not pinned, be mindful that the directory
+    is temporary (see {!is_source_dir_temporary}). *)
 val source_dir: 'a switch_state -> package -> dirname
 
+(** Returns [true] if the {!source_dir} of the package is meant to be a
+    temporary directory: packages that are not pinned or "dev package"
+    as defined in {!is_dev_package}. *)
+val is_source_dir_temporary: 'a switch_state -> package -> bool
+
 (** Returns the opam file overlay stored internally for pinned packages *)
 val overlay_opam_file:
   'a switch_state -> OpamPackage.Name.t -> OpamFile.OPAM.t OpamFile.t option