[Feature] Add an .editorconfig so dotnet format and the build enforce the code conventions (#86)

.editorconfig

@@ -0,0 +1,142 @@
+# EditorConfig for ArgusTransfer - states the conventions of CLAUDE.md and .github/CONTRIBUTING.md
+# so that the editor shows them and 'dotnet format --verify-no-changes' and the build enforce them.
+# https://editorconfig.org
+
+root = true
+
+##########################################
+# All files
+##########################################
+
+[*]
+charset = utf-8
+insert_final_newline = true
+trim_trailing_whitespace = true
+indent_style = space
+indent_size = 4
+
+[*.{cs,csproj,props,sln}]
+# pinned to CRLF on every platform by .gitattributes
+end_of_line = crlf
+
+[*.{yml,yaml,json}]
+indent_size = 2
+
+[*.md]
+# two trailing spaces are a line break in Markdown
+trim_trailing_whitespace = false
+
+##########################################
+# C# files
+##########################################
+
+[*.cs]
+indent_size = 4
+tab_width = 4
+
+# --- file header (CLAUDE.md: License header); IDE0073 also checks the file name in the header ---
+file_header_template = ------------------------------------------------------------------------------------------------\n<copyright file="{fileName}">\n\n  Copyright (c) 2025-2026 Sam Gerené\n  SPDX-License-Identifier: Apache-2.0\n\n</copyright>\n------------------------------------------------------------------------------------------------
+dotnet_diagnostic.IDE0073.severity = warning
+
+# --- layout: Allman braces ---
+csharp_new_line_before_open_brace = all
+csharp_new_line_before_else = true
+csharp_new_line_before_catch = true
+csharp_new_line_before_finally = true
+dotnet_diagnostic.IDE0055.severity = warning
+
+# --- using directives: inside the namespace, System first, a blank line between groups ---
+csharp_using_directive_placement = inside_namespace:warning
+dotnet_sort_system_directives_first = true
+dotnet_separate_import_directive_groups = true
+dotnet_diagnostic.IDE0065.severity = warning
+
+# --- block-scoped namespaces ---
+csharp_style_namespace_declarations = block_scoped:warning
+dotnet_diagnostic.IDE0160.severity = warning
+
+# --- 'this.' for instance members ---
+dotnet_style_qualification_for_field = true:warning
+dotnet_style_qualification_for_property = true:warning
+dotnet_style_qualification_for_method = true:warning
+dotnet_style_qualification_for_event = true:warning
+dotnet_diagnostic.IDE0009.severity = warning
+
+# --- language keywords instead of framework type names (int, string, not Int32, String) ---
+dotnet_style_predefined_type_for_locals_parameters_members = true:warning
+dotnet_style_predefined_type_for_member_access = true:warning
+dotnet_diagnostic.IDE0049.severity = warning
+
+# --- always braces, also for a single line ---
+csharp_prefer_braces = true:warning
+dotnet_diagnostic.IDE0011.severity = warning
+
+# --- 'var' unless the inferred type is not obvious ---
+csharp_style_var_for_built_in_types = true:suggestion
+csharp_style_var_when_type_is_apparent = true:suggestion
+csharp_style_var_elsewhere = true:suggestion
+
+# --- naming; Roslyn applies the first matching rule, so the specific ones come first ---
+dotnet_naming_style.pascal_case_style.capitalization = pascal_case
+dotnet_naming_style.camel_case_style.capitalization = camel_case
+dotnet_naming_style.interface_style.capitalization = pascal_case
+dotnet_naming_style.interface_style.required_prefix = I
+dotnet_naming_style.type_parameter_style.capitalization = pascal_case
+dotnet_naming_style.type_parameter_style.required_prefix = T
+
+dotnet_naming_symbols.private_const_fields_symbols.applicable_kinds = field
+dotnet_naming_symbols.private_const_fields_symbols.applicable_accessibilities = private, private_protected
+dotnet_naming_symbols.private_const_fields_symbols.required_modifiers = const
+dotnet_naming_symbols.private_static_readonly_fields_symbols.applicable_kinds = field
+dotnet_naming_symbols.private_static_readonly_fields_symbols.applicable_accessibilities = private, private_protected
+dotnet_naming_symbols.private_static_readonly_fields_symbols.required_modifiers = static, readonly
+dotnet_naming_symbols.private_fields_symbols.applicable_kinds = field
+dotnet_naming_symbols.private_fields_symbols.applicable_accessibilities = private, private_protected
+dotnet_naming_symbols.non_private_fields_symbols.applicable_kinds = field
+dotnet_naming_symbols.non_private_fields_symbols.applicable_accessibilities = public, internal, protected, protected_internal
+dotnet_naming_symbols.interfaces_symbols.applicable_kinds = interface
+dotnet_naming_symbols.interfaces_symbols.applicable_accessibilities = *
+dotnet_naming_symbols.type_parameters_symbols.applicable_kinds = type_parameter
+dotnet_naming_symbols.type_parameters_symbols.applicable_accessibilities = *
+dotnet_naming_symbols.methods_symbols.applicable_kinds = method, local_function
+dotnet_naming_symbols.methods_symbols.applicable_accessibilities = *
+dotnet_naming_symbols.types_and_members_symbols.applicable_kinds = namespace, class, struct, enum, delegate, property, event
+dotnet_naming_symbols.types_and_members_symbols.applicable_accessibilities = *
+dotnet_naming_symbols.parameters_and_locals_symbols.applicable_kinds = parameter, local
+dotnet_naming_symbols.parameters_and_locals_symbols.applicable_accessibilities = *
+
+dotnet_naming_rule.private_const_fields_are_pascal_case.symbols = private_const_fields_symbols
+dotnet_naming_rule.private_const_fields_are_pascal_case.style = pascal_case_style
+dotnet_naming_rule.private_const_fields_are_pascal_case.severity = warning
+dotnet_naming_rule.private_static_readonly_fields_are_pascal_case.symbols = private_static_readonly_fields_symbols
+dotnet_naming_rule.private_static_readonly_fields_are_pascal_case.style = pascal_case_style
+dotnet_naming_rule.private_static_readonly_fields_are_pascal_case.severity = warning
+dotnet_naming_rule.private_fields_are_camel_case.symbols = private_fields_symbols
+dotnet_naming_rule.private_fields_are_camel_case.style = camel_case_style
+dotnet_naming_rule.private_fields_are_camel_case.severity = warning
+dotnet_naming_rule.non_private_fields_are_pascal_case.symbols = non_private_fields_symbols
+dotnet_naming_rule.non_private_fields_are_pascal_case.style = pascal_case_style
+dotnet_naming_rule.non_private_fields_are_pascal_case.severity = warning
+dotnet_naming_rule.interfaces_are_prefixed.symbols = interfaces_symbols
+dotnet_naming_rule.interfaces_are_prefixed.style = interface_style
+dotnet_naming_rule.interfaces_are_prefixed.severity = warning
+dotnet_naming_rule.type_parameters_are_prefixed.symbols = type_parameters_symbols
+dotnet_naming_rule.type_parameters_are_prefixed.style = type_parameter_style
+dotnet_naming_rule.type_parameters_are_prefixed.severity = warning
+dotnet_naming_rule.methods_are_pascal_case.symbols = methods_symbols
+dotnet_naming_rule.methods_are_pascal_case.style = pascal_case_style
+dotnet_naming_rule.methods_are_pascal_case.severity = warning
+dotnet_naming_rule.types_and_members_are_pascal_case.symbols = types_and_members_symbols
+dotnet_naming_rule.types_and_members_are_pascal_case.style = pascal_case_style
+dotnet_naming_rule.types_and_members_are_pascal_case.severity = warning
+dotnet_naming_rule.parameters_and_locals_are_camel_case.symbols = parameters_and_locals_symbols
+dotnet_naming_rule.parameters_and_locals_are_camel_case.style = camel_case_style
+dotnet_naming_rule.parameters_and_locals_are_camel_case.severity = warning
+dotnet_diagnostic.IDE1006.severity = warning
+
+##########################################
+# Tests - test methods are named Verify_that_{scenario_in_snake_case} (CLAUDE.md: Testing Conventions)
+##########################################
+
+[ArgusTransfer.Tests/**.cs]
+dotnet_naming_rule.methods_are_pascal_case.severity = none

.gitattributes

@@ -0,0 +1,13 @@
+# Line-ending policy, independent of a contributor's git configuration (core.autocrlf).
+# Text files are stored with LF in the repository.
+* text=auto
+
+# C# sources and the project files are CRLF in the working tree on every platform. The .editorconfig
+# states the same (end_of_line = crlf), so 'dotnet format --verify-no-changes' gives the same result
+# on Windows, Linux and macOS.
+*.cs     text eol=crlf
+*.csproj text eol=crlf
+*.props  text eol=crlf
+*.sln    text eol=crlf
+
+*.png binary

.github/CONTRIBUTING.md

@@ -61,5 +61,19 @@ And remember; **A pull-request with tests is a pull-request that's likely to be
 - Put `using` statements inside namespace.
 - Pay attention to whitespace and extra blank lines
 - Absolutely **no** regions
-
-> If you are a ReSharper user, you can make use of our `.DotSettings` file to ensure you cover as many of our style guidelines as possible. There may be some style guidelines which are not covered by the file, so please pay attention to the style of existing code.
+- Start every `.cs` file with the short copyright header shown below, with the `file="..."` attribute equal to the name of the file:
+
+```csharp
+// ------------------------------------------------------------------------------------------------
+// <copyright file="MyClass.cs">
+//
+//   Copyright (c) 2025-2026 Sam Gerené
+//   SPDX-License-Identifier: Apache-2.0
+//
+// </copyright>
+// ------------------------------------------------------------------------------------------------
+```
+
+The `.editorconfig` in the root of the repository states these guidelines, so Visual Studio, Rider and VS Code show violations while you type. Before you send a pull request, run `dotnet format ArgusTransfer.sln` to apply them (it also adds the header to a new file) and `dotnet build ArgusTransfer.sln -warnaserror` to check them; the build of a pull request runs `dotnet format ArgusTransfer.sln --verify-no-changes`.
+
+> If you are a ReSharper or Rider user, the `.DotSettings` file adds the file header template and the naming rules for ReSharper; ReSharper and Rider read the `.editorconfig` as well. Some style guidelines are not covered by either file (regions, descriptive names), so please pay attention to the style of existing code.

.github/workflows/CodeQuality.yml

@@ -47,6 +47,11 @@ jobs:
           SONAR_TOKEN: ${{ secrets.SONAR_TOKEN }}  
         run: dotnet sonarscanner end /d:sonar.token="$SONAR_TOKEN"
 
+      # Checks the rules of .editorconfig: whitespace, line endings, encoding, using order, the file header and code style.
+      # Last, so that a violation does not stop the analysis above.
+      - name: Verify formatting
+        run: dotnet format ArgusTransfer.sln --no-restore --verify-no-changes
+
   # Named pipes behave differently on Windows (unbuffered pipe instances instead of Unix domain sockets), and some
   # tests only run there ([Platform("Win")]). Analysis and coverage stay in the Linux job above.
   test-windows:

ArgusTransfer.Sample/JsonArgusBodySerializer.cs

@@ -1,22 +1,11 @@
-// -------------------------------------------------------------------------------------------------
-//   <copyright file="JsonArgusBodySerializer.cs">
+// ------------------------------------------------------------------------------------------------
+// <copyright file="JsonArgusBodySerializer.cs">
 //
-//     Copyright (c) 2025-2026 Sam Gerené
+//   Copyright (c) 2025-2026 Sam Gerené
+//   SPDX-License-Identifier: Apache-2.0
 //
-//     Licensed under the Apache License, Version 2.0 (the "License");
-//     you may not use this file except in compliance with the License.
-//     You may obtain a copy of the License at
-//
-//         http://www.apache.org/licenses/LICENSE-2.0
-//
-//     Unless required by applicable law or agreed to in writing, software
-//     distributed under the License is distributed on an "AS IS" BASIS,
-//     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-//     See the License for the specific language governing permissions and
-//     limitations under the License.
-//
-//   </copyright>
-//   ------------------------------------------------------------------------------------------------
+// </copyright>
+// ------------------------------------------------------------------------------------------------
 
 namespace ArgusTransfer.Sample
 {

ArgusTransfer.Sample/Program.cs

@@ -1,22 +1,11 @@
-// -------------------------------------------------------------------------------------------------
-//   <copyright file="Program.cs">
+// ------------------------------------------------------------------------------------------------
+// <copyright file="Program.cs">
 //
-//     Copyright (c) 2025-2026 Sam Gerené
+//   Copyright (c) 2025-2026 Sam Gerené
+//   SPDX-License-Identifier: Apache-2.0
 //
-//     Licensed under the Apache License, Version 2.0 (the "License");
-//     you may not use this file except in compliance with the License.
-//     You may obtain a copy of the License at
-//
-//         http://www.apache.org/licenses/LICENSE-2.0
-//
-//     Unless required by applicable law or agreed to in writing, software
-//     distributed under the License is distributed on an "AS IS" BASIS,
-//     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-//     See the License for the specific language governing permissions and
-//     limitations under the License.
-//
-//   </copyright>
-//   ------------------------------------------------------------------------------------------------
+// </copyright>
+// ------------------------------------------------------------------------------------------------
 
 namespace ArgusTransfer.Sample
 {

ArgusTransfer.Sample/SampleApiKeyAuthenticationHandler.cs

@@ -1,22 +1,11 @@
-// -------------------------------------------------------------------------------------------------
-//   <copyright file="SampleApiKeyAuthenticationHandler.cs">
+// ------------------------------------------------------------------------------------------------
+// <copyright file="SampleApiKeyAuthenticationHandler.cs">
 //
-//     Copyright (c) 2025-2026 Sam Gerené
+//   Copyright (c) 2025-2026 Sam Gerené
+//   SPDX-License-Identifier: Apache-2.0
 //
-//     Licensed under the Apache License, Version 2.0 (the "License");
-//     you may not use this file except in compliance with the License.
-//     You may obtain a copy of the License at
-//
-//         http://www.apache.org/licenses/LICENSE-2.0
-//
-//     Unless required by applicable law or agreed to in writing, software
-//     distributed under the License is distributed on an "AS IS" BASIS,
-//     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-//     See the License for the specific language governing permissions and
-//     limitations under the License.
-//
-//   </copyright>
-//   ------------------------------------------------------------------------------------------------
+// </copyright>
+// ------------------------------------------------------------------------------------------------
 
 namespace ArgusTransfer.Sample
 {

ArgusTransfer.Sample/SampleClientService.cs

@@ -1,22 +1,11 @@
-// -------------------------------------------------------------------------------------------------
-//   <copyright file="SampleClientService.cs">
+// ------------------------------------------------------------------------------------------------
+// <copyright file="SampleClientService.cs">
 //
-//     Copyright (c) 2025-2026 Sam Gerené
+//   Copyright (c) 2025-2026 Sam Gerené
+//   SPDX-License-Identifier: Apache-2.0
 //
-//     Licensed under the Apache License, Version 2.0 (the "License");
-//     you may not use this file except in compliance with the License.
-//     You may obtain a copy of the License at
-//
-//         http://www.apache.org/licenses/LICENSE-2.0
-//
-//     Unless required by applicable law or agreed to in writing, software
-//     distributed under the License is distributed on an "AS IS" BASIS,
-//     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-//     See the License for the specific language governing permissions and
-//     limitations under the License.
-//
-//   </copyright>
-//   ------------------------------------------------------------------------------------------------
+// </copyright>
+// ------------------------------------------------------------------------------------------------
 
 namespace ArgusTransfer.Sample
 {
@@ -97,7 +86,7 @@
             Console.WriteLine();
 
             Console.WriteLine("--- Step 1: List all items; this endpoint allows anonymous callers ---");
             var request = CreateRequest(ArgusVerb.GET, "/sampleitems", authenticate: false);
             await this.SendAsync(request, ArgusStatusCode.Ok, stoppingToken);
 
             Console.WriteLine("--- Step 2: Create an item without credentials (expect 401 problem details) ---");

ArgusTransfer.Sample/SampleItem.cs

@@ -1,22 +1,11 @@
-// -------------------------------------------------------------------------------------------------
-//   <copyright file="SampleItem.cs">
+// ------------------------------------------------------------------------------------------------
+// <copyright file="SampleItem.cs">
 //
-//     Copyright (c) 2025-2026 Sam Gerené
+//   Copyright (c) 2025-2026 Sam Gerené
+//   SPDX-License-Identifier: Apache-2.0
 //
-//     Licensed under the Apache License, Version 2.0 (the "License");
-//     you may not use this file except in compliance with the License.
-//     You may obtain a copy of the License at
-//
-//         http://www.apache.org/licenses/LICENSE-2.0
-//
-//     Unless required by applicable law or agreed to in writing, software
-//     distributed under the License is distributed on an "AS IS" BASIS,
-//     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-//     See the License for the specific language governing permissions and
-//     limitations under the License.
-//
-//   </copyright>
-//   ------------------------------------------------------------------------------------------------
+// </copyright>
+// ------------------------------------------------------------------------------------------------
 
 namespace ArgusTransfer.Sample
 {

ArgusTransfer.Sample/SampleItemModule.cs

@@ -1,22 +1,11 @@
-// -------------------------------------------------------------------------------------------------
-//   <copyright file="SampleItemModule.cs">
+// ------------------------------------------------------------------------------------------------
+// <copyright file="SampleItemModule.cs">
 //
-//     Copyright (c) 2025-2026 Sam Gerené
+//   Copyright (c) 2025-2026 Sam Gerené
+//   SPDX-License-Identifier: Apache-2.0
 //
-//     Licensed under the Apache License, Version 2.0 (the "License");
-//     you may not use this file except in compliance with the License.
-//     You may obtain a copy of the License at
-//
-//         http://www.apache.org/licenses/LICENSE-2.0
-//
-//     Unless required by applicable law or agreed to in writing, software
-//     distributed under the License is distributed on an "AS IS" BASIS,
-//     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-//     See the License for the specific language governing permissions and
-//     limitations under the License.
-//
-//   </copyright>
-//   ------------------------------------------------------------------------------------------------
+// </copyright>
+// ------------------------------------------------------------------------------------------------
 
 namespace ArgusTransfer.Sample
 {

ArgusTransfer.Tests/Authentication/ArgusAuthenticationResultTestFixture.cs

@@ -1,22 +1,11 @@
-// -------------------------------------------------------------------------------------------------
-//   <copyright file="ArgusAuthenticationResultTestFixture.cs">
+// ------------------------------------------------------------------------------------------------
+// <copyright file="ArgusAuthenticationResultTestFixture.cs">
 //
-//     Copyright (c) 2025-2026 Sam Gerené
+//   Copyright (c) 2025-2026 Sam Gerené
+//   SPDX-License-Identifier: Apache-2.0
 //
-//     Licensed under the Apache License, Version 2.0 (the "License");
-//     you may not use this file except in compliance with the License.
-//     You may obtain a copy of the License at
-//
-//         http://www.apache.org/licenses/LICENSE-2.0
-//
-//     Unless required by applicable law or agreed to in writing, software
-//     distributed under the License is distributed on an "AS IS" BASIS,
-//     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-//     See the License for the specific language governing permissions and
-//     limitations under the License.
-//
-//   </copyright>
-//   ------------------------------------------------------------------------------------------------
+// </copyright>
+// ------------------------------------------------------------------------------------------------
 
 namespace ArgusTransfer.Tests.Authentication
 {