tests/package-option: downgrade some errors to warnings

I'm not yet planning to migrate all package options for plugins not yet
using `mkVimPlugin` or `mkNeovimPlugin` since that'll happen naturally
over time.

So I've made it so that these options print a warning but do not fail
the test.

Author: MattSturgeon

tests/package-options.nix

@@ -9,10 +9,14 @@ let
   inherit (builtins)
     filter
     head
+    length
     map
     match
+    partition
+    toString
     ;
   inherit (lib.strings) concatMapStringsSep removePrefix removeSuffix;
+  inherit (lib.lists) last;
   inherit (lib.attrsets) isDerivation;
   inherit (lib.options)
     isOption
@@ -37,51 +41,81 @@ let
 
   # Bad options do not use `literalExpression` in their `defaultText`,
   # or have a `defaultText` that doesn't start with "pkgs."
-  badOptions = filter (
-    opt:
-    opt.defaultText._type or null != "literalExpression"
-    || match ''pkgs[.].*'' (opt.defaultText.text or "") == null
-  ) drvOptions;
+  badOptions = lib.pipe drvOptions [
+    (filter (
+      opt:
+      opt.defaultText._type or null != "literalExpression"
+      || match ''pkgs[.].*'' (opt.defaultText.text or "") == null
+    ))
+    # Treat `plugins.*.package` errors as warnings
+    # TODO: upgrade these to errors once all plugins are migrated
+    (partition (opt: length opt.loc == 3 && last opt.loc == "package"))
+    (
+      { right, wrong }:
+      {
+        warnings = right;
+        errors = wrong;
+      }
+    )
+  ];
+
+  # Error strings to print
+  toErrorStrings =
+    let
+      # A little hack to get the flake's source in the nix store
+      # We will use this to make the option declaration sources more readable
+      src = removeSuffix "modules/top-level/output.nix" (
+        head evaluatedNixvim.options.package.declarations
+      );
+    in
+    map (
+      opt:
+      let
+        # The default, as rendered in documentation. Will always be a literalExpression.
+        default = builtins.addErrorContext "while evaluating the default text for `${showOption opt.loc}`" (
+          renderOptionValue (opt.defaultText or opt.default)
+        );
+      in
+      ''
+        - ${showOption opt.loc} (${default.text}), declared in:
+        ${concatMapStringsSep "\n" (file: "  - ${removePrefix src file}") opt.declarations}
+      ''
+    );
+
+  # Used to print warnings during eval
+  showWarnings =
+    if badOptions.warnings == [ ] then
+      lib.id
+    else
+      lib.warn ''
+
+        Found ${toString (length badOptions.warnings)} warnings:
+        ${lib.concatStrings (toErrorStrings badOptions.warnings)}
+        (${toString (length badOptions.warnings)}  options with warnings)
+      '';
 in
 runCommandNoCCLocal "validate-package-options"
-  {
+  (showWarnings {
     # Use structuredAttrs to avoid "Argument List Too Long" errors
     # and get proper bash array support.
     __structuredAttrs = true;
 
     # Passthroughs for debugging purposes
     passthru = {
       inherit evaluatedNixvim drvOptions badOptions;
+      warnings = toErrorStrings badOptions.warnings;
     };
 
     # Error strings to print
-    errors =
-      let
-        # A little hack to get the flake's source in the nix store
-        # We will use this to make the option declaration sources more readable
-        src = removeSuffix "modules/top-level/output.nix" (head evaluatedNixvim.options.package.declarations);
-      in
-      map (
-        opt:
-        let
-          # The default, as rendered in documentation. Will always be a literalExpression.
-          default = builtins.addErrorContext "while evaluating the default text for `${showOption opt.loc}`" (
-            renderOptionValue (opt.defaultText or opt.default)
-          );
-        in
-        ''
-          - ${showOption opt.loc} (${default.text}), declared in:
-          ${concatMapStringsSep "\n" (file: "  - ${removePrefix src file}") opt.declarations}
-        ''
-      ) badOptions;
-  }
+    errors = toErrorStrings badOptions.errors;
+  })
   ''
     if [ -n "$errors" ]; then
-      echo "Found ''${#errors[@]} issues:"
+      echo "Found ''${#errors[@]} errors:"
       for err in "''${errors[@]}"; do
         echo "$err"
       done
-      echo "(''${#errors[@]} options with issues)"
+      echo "(''${#errors[@]} options with errors)"
       exit 1
     fi
     touch $out