Update manifest after removal without rebuilding

Rename `manif.update_manifest` to `manif.add_to_manifest`.
Add `manif.remove_from_manifest` that performs reverse action.
Use it in `repos.delete_version` to avoid rebuilding manifest
everytime a package is removed.

2 files changed, 84 insertions, 9 deletions

diff --git a/src/luarocks/manif.lua b/src/luarocks/manif.lua
index 9213f362..c4c52bd2 100644
--- a/src/luarocks/manif.lua
+++ b/src/luarocks/manif.lua
@@ -185,6 +185,37 @@ local function store_package_items(storage, name, version, items)
    end
 end
 
+--- Update storage table removing items provided by a package.
+-- @param storage table: a table storing items in the following format:
+-- keys are item names and values are arrays of packages providing each item,
+-- where a package is specified as string `name/version`.
+-- @param items table: a table mapping item names to paths.
+-- @param name string: package name.
+-- @param version string: package version.
+local function remove_package_items(storage, name, version, items)
+   assert(type(storage) == "table")
+   assert(type(items) == "table")
+   assert(type(name) == "string")
+   assert(type(version) == "string")
+
+   local package_identifier = name.."/"..version
+
+   for item_name, path in pairs(items) do
+      local all_identifiers = storage[item_name]
+
+      for i, identifier in ipairs(all_identifiers) do
+         if identifier == package_identifier then
+            table.remove(all_identifiers, i)
+            break
+         end
+      end
+
+      if #all_identifiers == 0 then
+         storage[item_name] = nil
+      end
+   end
+end
+
 --- Sort function for ordering rock identifiers in a manifest's
 -- modules table. Rocks are ordered alphabetically by name, and then
 -- by version which greater first.
@@ -398,10 +429,8 @@ function manif.make_manifest(repo, deps_mode, remote)
    return save_table(repo, "manifest", manifest)
 end
 
---- Load a manifest file from a local repository and add to the repository
--- information with regard to the given name and version.
--- A file called 'manifest' will be written in the root of the given
--- repository directory.
+--- Update manifest file for a local repository
+-- adding information about a version of a package installed in that repository.
 -- @param name string: Name of a package from the repository.
 -- @param version string: Version of a package from the repository.
 -- @param repo string or nil: Pathname of a local repository. If not given,
@@ -409,14 +438,14 @@ end
 -- @param deps_mode string: Dependency mode: "one" for the current default tree,
 -- "all" for all trees, "order" for all trees with priority >= the current default,
 -- "none" for using the default dependency mode from the configuration.
--- @return boolean or (nil, string): True if manifest was generated,
+-- @return boolean or (nil, string): True if manifest was updated successfully,
 -- or nil and an error message.
-function manif.update_manifest(name, version, repo, deps_mode)
+function manif.add_to_manifest(name, version, repo, deps_mode)
    assert(type(name) == "string")
    assert(type(version) == "string")
    local rocks_dir = path.rocks_dir(repo or cfg.root_dir)
    assert(type(deps_mode) == "string")
-   
+
    if deps_mode == "none" then deps_mode = cfg.deps_mode end
 
    local manifest, err = manif_core.load_local_manifest(rocks_dir)
@@ -437,6 +466,52 @@ function manif.update_manifest(name, version, repo, deps_mode)
    return save_table(rocks_dir, "manifest", manifest)
 end
 
+--- Update manifest file for a local repository
+-- removing information about a version of a package.
+-- @param name string: Name of a package removed from the repository.
+-- @param version string: Version of a package removed from the repository.
+-- @param repo string or nil: Pathname of a local repository. If not given,
+-- the default local repository is used.
+-- @param deps_mode string: Dependency mode: "one" for the current default tree,
+-- "all" for all trees, "order" for all trees with priority >= the current default,
+-- "none" for using the default dependency mode from the configuration.
+-- @return boolean or (nil, string): True if manifest was updated successfully,
+-- or nil and an error message.
+function manif.remove_from_manifest(name, version, repo, deps_mode)
+   assert(type(name) == "string")
+   assert(type(version) == "string")
+   local rocks_dir = path.rocks_dir(repo or cfg.root_dir)
+   assert(type(deps_mode) == "string")
+
+   if deps_mode == "none" then deps_mode = cfg.deps_mode end
+
+   local manifest, err = manif_core.load_local_manifest(rocks_dir)
+   if not manifest then
+      util.printerr("No existing manifest. Attempting to rebuild...")
+      -- Manifest built by `manif.make_manifest` should already
+      -- include up-to-date information, no need to update it.
+      return manif.make_manifest(rocks_dir, deps_mode)
+   end
+
+   local package_entry = manifest.repository[name]
+
+   local version_entry = package_entry[version][1]
+   remove_package_items(manifest.modules, name, version, version_entry.modules)
+   remove_package_items(manifest.commands, name, version, version_entry.commands)
+
+   package_entry[version] = nil
+   manifest.dependencies[name][version] = nil
+
+   if not next(package_entry) then
+      -- No more versions of this package.
+      manifest.repository[name] = nil
+      manifest.dependencies[name] = nil
+   end
+
+   update_dependencies(manifest, deps_mode)
+   return save_table(rocks_dir, "manifest", manifest)
+end
+
 function manif.zip_manifests()
    for ver in util.lua_versions() do
       local file = "manifest-"..ver
diff --git a/src/luarocks/repos.lua b/src/luarocks/repos.lua
index c5f157c4..d4d9694e 100644
--- a/src/luarocks/repos.lua
+++ b/src/luarocks/repos.lua
@@ -312,7 +312,7 @@ function repos.deploy_files(name, version, wrap_bin_scripts, deps_mode)
       return nil, err
    end
 
-   return manif.update_manifest(name, version, nil, deps_mode)
+   return manif.add_to_manifest(name, version, nil, deps_mode)
 end
 
 --- Delete a package from the local repository.
@@ -398,7 +398,7 @@ function repos.delete_version(name, version, deps_mode, quick)
       return true
    end
 
-   return manif.make_manifest(cfg.rocks_dir, deps_mode)
+   return manif.remove_from_manifest(name, version, nil, deps_mode)
 end
 
 return repos