Merge pull request #82743 from Infinisil/partially-typed-v2

Freeform modules

1 files changed, 110 insertions, 43 deletions

diff --git a/lib/modules.nix b/lib/modules.nix
index c18fec66c70..55a53b3909a 100644
--- a/lib/modules.nix
+++ b/lib/modules.nix
@@ -58,6 +58,23 @@ rec {
             default = check;
             description = "Whether to check whether all option definitions have matching declarations.";
           };
+
+          _module.freeformType = mkOption {
+            # Disallow merging for now, but could be implemented nicely with a `types.optionType`
+            type = types.nullOr (types.uniq types.attrs);
+            internal = true;
+            default = null;
+            description = ''
+              If set, merge all definitions that don't have an associated option
+              together using this type. The result then gets combined with the
+              values of all declared options to produce the final <literal>
+              config</literal> value.
+
+              If this is <literal>null</literal>, definitions without an option
+              will throw an error unless <option>_module.check</option> is
+              turned off.
+            '';
+          };
         };
 
         config = {
@@ -65,35 +82,44 @@ rec {
         };
       };
 
-      collected = collectModules
-        (specialArgs.modulesPath or "")
-        (modules ++ [ internalModule ])
-        ({ inherit config options lib; } // specialArgs);
-
-      options = mergeModules prefix (reverseList collected);
-
-      # Traverse options and extract the option values into the final
-      # config set.  At the same time, check whether all option
-      # definitions have matching declarations.
-      # !!! _module.check's value can't depend on any other config values
-      # without an infinite recursion. One way around this is to make the
-      # 'config' passed around to the modules be unconditionally unchecked,
-      # and only do the check in 'result'.
-      config = yieldConfig prefix options;
-      yieldConfig = prefix: set:
-        let res = removeAttrs (mapAttrs (n: v:
-          if isOption v then v.value
-          else yieldConfig (prefix ++ [n]) v) set) ["_definedNames"];
-        in
-        if options._module.check.value && set ? _definedNames then
-          foldl' (res: m:
-            foldl' (res: name:
-              if set ? ${name} then res else throw "The option `${showOption (prefix ++ [name])}' defined in `${m.file}' does not exist.")
-              res m.names)
-            res set._definedNames
-        else
-          res;
-      result = {
+      merged =
+        let collected = collectModules
+          (specialArgs.modulesPath or "")
+          (modules ++ [ internalModule ])
+          ({ inherit lib options config; } // specialArgs);
+        in mergeModules prefix (reverseList collected);
+
+      options = merged.matchedOptions;
+
+      config =
+        let
+
+          # For definitions that have an associated option
+          declaredConfig = mapAttrsRecursiveCond (v: ! isOption v) (_: v: v.value) options;
+
+          # If freeformType is set, this is for definitions that don't have an associated option
+          freeformConfig =
+            let
+              defs = map (def: {
+                file = def.file;
+                value = setAttrByPath def.prefix def.value;
+              }) merged.unmatchedDefns;
+            in if defs == [] then {}
+            else declaredConfig._module.freeformType.merge prefix defs;
+
+        in if declaredConfig._module.freeformType == null then declaredConfig
+          # Because all definitions that had an associated option ended in
+          # declaredConfig, freeformConfig can only contain the non-option
+          # paths, meaning recursiveUpdate will never override any value
+          else recursiveUpdate freeformConfig declaredConfig;
+
+      checkUnmatched =
+        if config._module.check && config._module.freeformType == null && merged.unmatchedDefns != [] then
+          let inherit (head merged.unmatchedDefns) file prefix;
+          in throw "The option `${showOption prefix}' defined in `${file}' does not exist."
+        else null;
+
+      result = builtins.seq checkUnmatched {
         inherit options;
         config = removeAttrs config [ "_module" ];
         inherit (config) _module;
@@ -174,12 +200,16 @@ rec {
   /* Massage a module into canonical form, that is, a set consisting
      of ‘options’, ‘config’ and ‘imports’ attributes. */
   unifyModuleSyntax = file: key: m:
-    let addMeta = config: if m ? meta
-      then mkMerge [ config { meta = m.meta; } ]
-      else config;
+    let
+      addMeta = config: if m ? meta
+        then mkMerge [ config { meta = m.meta; } ]
+        else config;
+      addFreeformType = config: if m ? freeformType
+        then mkMerge [ config { _module.freeformType = m.freeformType; } ]
+        else config;
     in
     if m ? config || m ? options then
-      let badAttrs = removeAttrs m ["_file" "key" "disabledModules" "imports" "options" "config" "meta"]; in
+      let badAttrs = removeAttrs m ["_file" "key" "disabledModules" "imports" "options" "config" "meta" "freeformType"]; in
       if badAttrs != {} then
         throw "Module `${key}' has an unsupported attribute `${head (attrNames badAttrs)}'. This is caused by introducing a top-level `config' or `options' attribute. Add configuration attributes immediately on the top level instead, or move all of them (namely: ${toString (attrNames badAttrs)}) into the explicit `config' attribute."
       else
@@ -188,7 +218,7 @@ rec {
           disabledModules = m.disabledModules or [];
           imports = m.imports or [];
           options = m.options or {};
-          config = addMeta (m.config or {});
+          config = addFreeformType (addMeta (m.config or {}));
         }
     else
       { _file = m._file or file;
@@ -196,7 +226,7 @@ rec {
         disabledModules = m.disabledModules or [];
         imports = m.require or [] ++ m.imports or [];
         options = {};
-        config = addMeta (removeAttrs m ["_file" "key" "disabledModules" "require" "imports"]);
+        config = addFreeformType (addMeta (removeAttrs m ["_file" "key" "disabledModules" "require" "imports" "freeformType"]));
       };
 
   applyIfFunction = key: f: args@{ config, options, lib, ... }: if isFunction f then
@@ -233,7 +263,23 @@ rec {
      declarations in all modules, combining them into a single set.
      At the same time, for each option declaration, it will merge the
      corresponding option definitions in all machines, returning them
-     in the ‘value’ attribute of each option. */
+     in the ‘value’ attribute of each option.
+
+     This returns a set like
+       {
+         # A recursive set of options along with their final values
+         matchedOptions = {
+           foo = { _type = "option"; value = "option value of foo"; ... };
+           bar.baz = { _type = "option"; value = "option value of bar.baz"; ... };
+           ...
+         };
+         # A list of definitions that weren't matched by any option
+         unmatchedDefns = [
+           { file = "file.nix"; prefix = [ "qux" ]; value = "qux"; }
+           ...
+         ];
+       }
+  */
   mergeModules = prefix: modules:
     mergeModules' prefix modules
       (concatMap (m: map (config: { file = m._file; inherit config; }) (pushDownProperties m.config)) modules);
@@ -280,9 +326,9 @@ rec {
       defnsByName' = byName "config" (module: value:
           [{ inherit (module) file; inherit value; }]
         ) configs;
-    in
-    (flip mapAttrs declsByName (name: decls:
-      # We're descending into attribute ‘name’.
+
+      resultsByName = flip mapAttrs declsByName (name: decls:
+        # We're descending into attribute ‘name’.
         let
           loc = prefix ++ [name];
           defns = defnsByName.${name} or [];
@@ -291,7 +337,10 @@ rec {
         in
           if nrOptions == length decls then
             let opt = fixupOptionType loc (mergeOptionDecls loc decls);
-            in evalOptionValue loc opt defns'
+            in {
+              matchedOptions = evalOptionValue loc opt defns';
+              unmatchedDefns = [];
+            }
           else if nrOptions != 0 then
             let
               firstOption = findFirst (m: isOption m.options) "" decls;
@@ -299,9 +348,27 @@ rec {
             in
               throw "The option `${showOption loc}' in `${firstOption._file}' is a prefix of options in `${firstNonOption._file}'."
           else
-            mergeModules' loc decls defns
-      ))
-    // { _definedNames = map (m: { inherit (m) file; names = attrNames m.config; }) configs; };
+            mergeModules' loc decls defns);
+
+      matchedOptions = mapAttrs (n: v: v.matchedOptions) resultsByName;
+
+      # an attrset 'name' => list of unmatched definitions for 'name'
+      unmatchedDefnsByName =
+        # Propagate all unmatched definitions from nested option sets
+        mapAttrs (n: v: v.unmatchedDefns) resultsByName
+        # Plus the definitions for the current prefix that don't have a matching option
+        // removeAttrs defnsByName' (attrNames matchedOptions);
+    in {
+      inherit matchedOptions;
+
+      # Transforms unmatchedDefnsByName into a list of definitions
+      unmatchedDefns = concatLists (mapAttrsToList (name: defs:
+        map (def: def // {
+          # Set this so we know when the definition first left unmatched territory
+          prefix = [name] ++ (def.prefix or []);
+        }) defs
+      ) unmatchedDefnsByName);
+    };
 
   /* Merge multiple option declarations into a single declaration.  In
      general, there should be only one declaration of each option.