feat(dart): Add shared analyzer config and dart format pre-commit hook

nix/dart/default.nix

@@ -7,6 +7,8 @@
 importingFlake: {
   imports = [
     (importApply ./devshell.nix args)
+    (importApply ./linting.nix args)
+    (importApply ./pre-commit.nix args)
     (importApply ./sdk.nix args)
     ./workflow.nix
   ];

nix/dart/linting.nix

@@ -0,0 +1,42 @@
+# Dart linting configuration.
+#
+# For every configured Dart project, place the shared analyzer configuration
+# via filegen:
+#
+#   analysis_options.standards.yaml  — managed, always overwritten
+#   analysis_options.yaml            — created once, then owned by the repo
+#
+# The standards file drives `dart analyze`, the IDE analyzer, and the
+# `dart_code_linter` step of the Dart CI workflow, so local and CI analysis
+# share one source of truth.
+{ ... }:
+importingFlake: {
+  perSystem =
+    { config, lib, ... }:
+    let
+      projects = config.famedly.standards.dart.projects;
+
+      mkProjectFiles =
+        name: _:
+        let
+          dir = if name == "." then "" else "${lib.removePrefix "./" name}/";
+        in
+        [
+          {
+            type = "copy";
+            target = "./${dir}analysis_options.standards.yaml";
+            source = ../../standards/dart/analysis_options.standards.yaml;
+            clobber = true;
+          }
+          {
+            type = "copy";
+            target = "./${dir}analysis_options.yaml";
+            source = ../../standards/dart/analysis_options.yaml;
+            clobber = false;
+          }
+        ];
+    in
+    lib.mkIf (projects != { }) {
+      filegen.settings.files = lib.concatLists (lib.mapAttrsToList mkProjectFiles projects);
+    };
+}

nix/dart/pre-commit.nix

@@ -0,0 +1,40 @@
+# Dart pre-commit hooks.
+#
+# When the repository has Dart projects, register a `dart format` hook in the
+# root `prek` workspace and make the pinned Dart SDK available to the hook
+# runner.
+#
+# Only `dart format` runs here: it is dependency-free and fast. The
+# dependency-aware checks (analyze, import_sorter, dart_code_linter, …) need
+# `pub get` and therefore live in the Dart CI workflow instead of prek.
+{ ... }:
+importingFlake: {
+  perSystem =
+    {
+      config,
+      lib,
+      self',
+      ...
+    }:
+    lib.mkIf (config.famedly.standards.dart.projects != { }) {
+      prek-pre-commit = {
+        package.runtimePkgs = [ self'.packages.famedly-dart-sdk ];
+
+        workspaces.".".repos = [
+          {
+            repo = "local";
+            hooks = [
+              {
+                id = "dart-format";
+                name = "dart format";
+                description = "Format Dart code with the pinned SDK";
+                entry = "dart format";
+                language = "system";
+                types = [ "dart" ];
+              }
+            ];
+          }
+        ];
+      };
+    };
+}

standards/dart/analysis_options.standards.yaml

@@ -0,0 +1,66 @@
+# managed-by: engineering-standards — do not edit manually.
+#
+# This file is placed by the engineering-standards flake. Regenerate it with:
+#   nix run .#filegen-activate
+#
+# Put repo-specific overrides in analysis_options.yaml (which includes this
+# file), never here. Using these rules requires the following dev_dependencies:
+#   dev_dependencies:
+#     lints: ^6.0.0
+#     dart_code_linter: ^3.2.1
+include: package:lints/recommended.yaml
+
+linter:
+  rules:
+    - avoid_print
+    - constant_identifier_names
+    - prefer_final_locals
+    - prefer_final_in_for_each
+    - sort_pub_dependencies
+    - require_trailing_commas
+    - omit_local_variable_types
+    - cancel_subscriptions
+    - always_declare_return_types
+    - avoid_void_async
+    - no_adjacent_strings_in_list
+    - test_types_in_equals
+    - throw_in_finally
+    - unnecessary_statements
+    - avoid_bool_literals_in_conditional_expressions
+    - prefer_single_quotes
+    - prefer_const_declarations
+    - unnecessary_lambdas
+    - combinators_ordering
+    - noop_primitive_operations
+    - unnecessary_null_checks
+    - unnecessary_null_in_if_null_operators
+    - unnecessary_to_list_in_spreads
+    - use_is_even_rather_than_modulo
+    - use_super_parameters
+
+analyzer:
+  plugins:
+    - dart_code_linter
+  errors:
+    todo: ignore
+    use_build_context_synchronously: ignore
+  exclude:
+    - lib/l10n/*.dart
+
+dart_code_linter:
+  rules:
+    - avoid-dynamic
+    - avoid-redundant-async
+    - avoid-unnecessary-type-assertions
+    - avoid-unnecessary-type-casts
+    - avoid-unrelated-type-assertions
+    - no-equal-then-else
+    - prefer-first
+    - prefer-last
+    - prefer-immediate-return
+    - prefer-enums-by-name
+    - avoid-unnecessary-conditionals
+    - prefer-match-file-name
+    - member-ordering
+    - avoid-late-keyword
+    - avoid-global-state

standards/dart/analysis_options.yaml

@@ -0,0 +1,14 @@
+# Include the shared lint rules from engineering-standards.
+#
+# The standards file is managed by the engineering-standards flake; this file
+# is yours to customise. Add repo-specific overrides below the include.
+include: analysis_options.standards.yaml
+
+# Repo-specific overrides below this line.
+# See https://dart.dev/tools/analysis for available options. Example:
+#   analyzer:
+#     exclude:
+#       - example/**
+#   linter:
+#     rules:
+#       avoid_print: false  # https://github.com/famedly/REPO/issues/XXX