lib/modules: add suggestions to invalid option name errors (#442263)

lib/modules.nix

@@ -12,6 +12,7 @@ let
     concatMap
     concatStringsSep
     elem
+    elemAt
     filter
     foldl'
     functionArgs
@@ -20,12 +21,14 @@ let
     head
     id
     imap1
+    init
     isAttrs
     isBool
     isFunction
     oldestSupportedReleaseIsAtLeast
     isList
     isString
+    last
     length
     mapAttrs
     mapAttrsToList
@@ -34,12 +37,16 @@ let
     optional
     optionalAttrs
     optionalString
+    pipe
     recursiveUpdate
+    remove
     reverseList
     sort
+    sortOn
     seq
     setAttrByPath
     substring
+    take
     throwIfNot
     trace
     typeOf
@@ -60,6 +67,8 @@ let
     ;
   inherit (lib.strings)
     isConvertibleWithToString
+    levenshtein
+    levenshteinAtMost
     ;
 
   showDeclPrefix =
@@ -304,8 +313,41 @@ let
                   addErrorContext
                     "while evaluating the error message for definitions for `${optText}', which is an option that does not exist"
                     (addErrorContext "while evaluating a definition from `${firstDef.file}'" (showDefs [ firstDef ]));
+
+                # absInvalidOptionParent is absolute; other variables are relative to the submodule prefix
+                absInvalidOptionParent = init (prefix ++ firstDef.prefix);
+                invalidOptionParent = init firstDef.prefix;
+                siblingOptionNames = attrNames (attrByPath invalidOptionParent { } options);
+                candidateNames =
+                  if invalidOptionParent == [ ] then remove "_module" siblingOptionNames else siblingOptionNames;
+                invalidOptionName = last firstDef.prefix;
+                # For small option sets, check all; for large sets, only check distance ≤ 2
+                suggestions =
+                  if length candidateNames < 100 then
+                    pipe candidateNames [
+                      (sortOn (levenshtein invalidOptionName))
+                      (take 3)
+                    ]
+                  else
+                    pipe candidateNames [
+                      # levenshteinAtMost is only fast for distance ≤ 2
+                      (filter (levenshteinAtMost 2 invalidOptionName))
+                      (sortOn (levenshtein invalidOptionName))
+                      (take 3)
+                    ];
+                suggestion =
+                  if suggestions == [ ] then
+                    ""
+                  else if length suggestions == 1 then
+                    "\n\nDid you mean `${showOption (absInvalidOptionParent ++ [ (head suggestions) ])}'?"
+                  else
+                    "\n\nDid you mean ${
+                      concatStringsSep ", " (
+                        map (s: "`${showOption (absInvalidOptionParent ++ [ s ])}'") (init suggestions)
+                      )
+                    } or `${showOption (absInvalidOptionParent ++ [ (last suggestions) ])}'?";
               in
-              "The option `${optText}' does not exist. Definition values:${defText}";
+              "The option `${optText}' does not exist. Definition values:${defText}${suggestion}";
           in
           if
             attrNames options == [ "_module" ]

lib/tests/modules.sh

@@ -870,6 +870,14 @@ checkConfigError 'A definition for option .* is not of type .*' config.addCheckF
 checkConfigOutput '^true$' config.result ./v2-check-coherence.nix
 
 
+# Option name suggestions
+checkConfigError 'Did you mean .set\.enable.\?' config.set ./error-typo-nested.nix
+checkConfigError 'Did you mean .set.\?' config ./error-typo-outside-with-nested.nix
+checkConfigError 'Did you mean .bar., .baz. or .foo.\?' config ./error-typo-multiple-suggestions.nix
+checkConfigError 'Did you mean .enable., .ebe. or .enabled.\?' config ./error-typo-large-attrset.nix
+checkConfigError 'Did you mean .services\.myservice\.port. or .services\.myservice\.enable.\?' config.services.myservice ./error-typo-submodule.nix
+checkConfigError 'Did you mean .services\.nginx\.virtualHosts\."example\.com"\.ssl\.certificate. or .services\.nginx\.virtualHosts\."example\.com"\.ssl\.certificateKey.\?' config.services.nginx.virtualHosts.\"example.com\" ./error-typo-deeply-nested.nix
+
 cat <<EOF
 ====== module tests ======
 $pass Pass

lib/tests/modules/error-typo-deeply-nested.nix

@@ -0,0 +1,42 @@
+{ lib, ... }:
+
+{
+  options.services = {
+    nginx = {
+      enable = lib.mkOption {
+        default = false;
+        type = lib.types.bool;
+      };
+      virtualHosts = lib.mkOption {
+        type = lib.types.attrsOf (
+          lib.types.submodule {
+            options = {
+              enableSSL = lib.mkOption {
+                default = false;
+                type = lib.types.bool;
+              };
+              ssl = {
+                certificate = lib.mkOption {
+                  default = "";
+                  type = lib.types.str;
+                };
+                certificateKey = lib.mkOption {
+                  default = "";
+                  type = lib.types.str;
+                };
+              };
+            };
+          }
+        );
+        default = { };
+      };
+    };
+  };
+
+  config = {
+    services.nginx.virtualHosts."example.com" = {
+      # Typo: "certficate" instead of "certificate" (nested within submodule)
+      ssl.certficate = "/path/to/cert";
+    };
+  };
+}

lib/tests/modules/error-typo-large-attrset.nix

@@ -0,0 +1,56 @@
+{ lib, ... }:
+
+let
+  inherit (lib) mkOption concatMapAttrs;
+
+  ten = {
+    a = null;
+    b = null;
+    c = null;
+    d = null;
+    e = null;
+    f = null;
+    g = null;
+    h = null;
+    i = null;
+    j = null;
+  };
+
+  # Generate 1000 options (10 * 10 * 10)
+  generatedOptions = concatMapAttrs (
+    k1: _:
+    concatMapAttrs (
+      k2: _:
+      concatMapAttrs (k3: _: {
+        "${k1}${k2}${k3}" = mkOption {
+          type = lib.types.bool;
+          default = false;
+        };
+      }) ten
+    ) ten
+  ) ten;
+
+  # Add some sensible options that are close to our typo
+  sensibleOptions = {
+    enable = mkOption {
+      type = lib.types.bool;
+      default = false;
+    };
+    enabled = mkOption {
+      type = lib.types.bool;
+      default = false;
+    };
+    disable = mkOption {
+      type = lib.types.bool;
+      default = false;
+    };
+  };
+in
+{
+  options = generatedOptions // sensibleOptions;
+
+  config = {
+    # Typo: "enble" is distance 1 from "enable"
+    enble = true;
+  };
+}

lib/tests/modules/error-typo-multiple-suggestions.nix

@@ -0,0 +1,22 @@
+{ lib, ... }:
+
+{
+  options.foo = lib.mkOption {
+    default = false;
+    type = lib.types.bool;
+  };
+
+  options.bar = lib.mkOption {
+    default = false;
+    type = lib.types.bool;
+  };
+
+  options.baz = lib.mkOption {
+    default = false;
+    type = lib.types.bool;
+  };
+
+  config = {
+    far = true;
+  };
+}

lib/tests/modules/error-typo-nested.nix

@@ -0,0 +1,18 @@
+{ lib, ... }:
+
+{
+  options.set = {
+    enable = lib.mkOption {
+      default = false;
+      example = true;
+      type = lib.types.bool;
+      description = ''
+        Some descriptive text
+      '';
+    };
+  };
+
+  config = {
+    set.ena = true;
+  };
+}

lib/tests/modules/error-typo-outside-with-nested.nix

@@ -0,0 +1,18 @@
+{ lib, ... }:
+
+{
+  options.set = {
+    enable = lib.mkOption {
+      default = false;
+      example = true;
+      type = lib.types.bool;
+      description = ''
+        Some descriptive text
+      '';
+    };
+  };
+
+  config = {
+    sea.enable = true;
+  };
+}

lib/tests/modules/error-typo-submodule.nix

@@ -0,0 +1,28 @@
+{ lib, ... }:
+
+{
+  options.services = lib.mkOption {
+    type = lib.types.attrsOf (
+      lib.types.submodule {
+        options = {
+          enable = lib.mkOption {
+            default = false;
+            type = lib.types.bool;
+          };
+          port = lib.mkOption {
+            default = 8080;
+            type = lib.types.int;
+          };
+        };
+      }
+    );
+    default = { };
+  };
+
+  config = {
+    services.myservice = {
+      # Typo: "prot" instead of "port"
+      prot = 9000;
+    };
+  };
+}