feat: add Build:CSharpierPath to run a vendored CSharpier assembly

README.md

@@ -160,7 +160,7 @@ CleanArtifacts → { Version, Restore → Build → Test, Restore → Lint } →
 
 `Lint` and `ReportEligibility` are gates and reports, not inputs: nothing depends on either.
 
-`CleanArtifacts` deletes and recreates `Build:ArtifactsFolder` before anything else runs, so pack, validation, publishing, and release uploads only ever see the packages from the current run (set `Build:CleanArtifacts=false` to keep existing artifacts). `Version` resolves the release units from `Version:Source` (default: the `version` field of the root `package.json`); `Version:Strictness` defaults to `NuGet`, which accepts four-part versions. `ReportEligibility` evaluates the release rules and reports the verdict without acting on it. Lint restores local tools and runs CSharpier. Tests are discovered under `Build:TestRoot`/`Build:TestPatterns` and run with a TUnit tree-node filter (or an xUnit filter). Pack validation inspects each `.nupkg`/`.snupkg` against required/forbidden content rules (glob patterns) and can enforce source link, deterministic builds, and compiler flags on the packaged assemblies. Analyzer-only packages can embed portable PDBs under `analyzers/dotnet/` without requiring a `.snupkg`. Publication and GitHub release steps are controlled by `Release:Mode` (`None`, `LocalNuGet`, `NuGet`, `GitHubRelease`) — a preset over the independent `Release:Publish` and `Release:GitHubRelease` switches — and by the `Build__Run*` switches. `Release:DryRun` runs everything and skips both publish steps. `LocalNuGet` is only honoured when the tool runs locally; it is ignored in CI (for example via a reusable workflow).
+`CleanArtifacts` deletes and recreates `Build:ArtifactsFolder` before anything else runs, so pack, validation, publishing, and release uploads only ever see the packages from the current run (set `Build:CleanArtifacts=false` to keep existing artifacts). `Version` resolves the release units from `Version:Source` (default: the `version` field of the root `package.json`); `Version:Strictness` defaults to `NuGet`, which accepts four-part versions. `ReportEligibility` evaluates the release rules and reports the verdict without acting on it. Lint restores local tools and runs CSharpier (`Build:CSharpierPath` runs a vendored CSharpier assembly instead, for an unreleased build). Tests are discovered under `Build:TestRoot`/`Build:TestPatterns` and run with a TUnit tree-node filter (or an xUnit filter). Pack validation inspects each `.nupkg`/`.snupkg` against required/forbidden content rules (glob patterns) and can enforce source link, deterministic builds, and compiler flags on the packaged assemblies. Analyzer-only packages can embed portable PDBs under `analyzers/dotnet/` without requiring a `.snupkg`. Publication and GitHub release steps are controlled by `Release:Mode` (`None`, `LocalNuGet`, `NuGet`, `GitHubRelease`) — a preset over the independent `Release:Publish` and `Release:GitHubRelease` switches — and by the `Build__Run*` switches. `Release:DryRun` runs everything and skips both publish steps. `LocalNuGet` is only honoured when the tool runs locally; it is ignored in CI (for example via a reusable workflow).
 
 ## Repository CI/CD
 

docs/wiki/Configuration-Reference.md

@@ -130,6 +130,7 @@ Malformed JSON in a configuration file fails with the file path and, where the p
 | `TestFramework` | `TUnit` | `TUnit` (tree-node filter) or `xUnit` (VSTest filter) |
 | `TestFilter` | `/*/*/*/*/` | TUnit tree-node filter or xUnit `--filter`; empty disables it |
 | `RunLint` | `true` | Restore local tools and run CSharpier check (dotnet) or `format:check` + `lint` scripts (Web) |
+| `CSharpierPath` | unset | Path (relative to the repository root, or absolute) to a CSharpier CLI `.dll` to run with `dotnet` instead of the `dotnet-tools.json` manifest tool. For a repository that needs an unreleased CSharpier build, for example C# 15 union support (dotnet only) |
 | `RunPack` | `true` | Enable packing |
 | `ValidatePack` | `true` | Enable pack validation (dotnet only; always skipped for Web) |
 | `WebInstallCommand` | `bun install` | Install command for `ProjectType=Web` |

docs/wiki/Pipeline-Modules.md

@@ -53,7 +53,7 @@ Depends on `RestoreModule`.
 
 Depends on `RestoreModule` (Web lint invokes tooling installed by the restore step, so it must wait for `bun install`; dotnet lint is unaffected beyond running after restore). Skip condition: skipped when `Build:RunLint` is false.
 
-- **DotNet**: restores the repository's local tools (`dotnet tool restore` against `.config/dotnet-tools.json`, retried up to 3 times with a 2-second backoff on failure) and then runs `dotnet tool run csharpier check <repository root>`. The repository root is resolved by walking up to the nearest `package.json`.
+- **DotNet**: restores the repository's local tools (`dotnet tool restore` against `.config/dotnet-tools.json`, retried up to 3 times with a 2-second backoff on failure) and then runs `dotnet tool run csharpier check <repository root>`. The repository root is resolved by walking up to the nearest `package.json`. When `Build:CSharpierPath` is set, the manifest tool is bypassed: the module runs `dotnet <path> check <repository root>` against the vendored assembly instead and does not restore local tools.
 - **Web**: runs `Build:WebFormatCheckCommand` (default `bun run format:check`) then `Build:WebLintCommand` (default `bun run lint`). Each step is skipped when the corresponding script is not declared in the root `package.json`.
 
 ## RunTestsModule

package.json

@@ -1,6 +1,6 @@
 {
   "name": "build",
-  "version": "0.5.4",
+  "version": "0.6.0",
   "description": "Shared build/test/release pipeline for the purview-dev organisation, packaged as a pinned .NET tool with a GitHub composite action and reusable workflows.",
   "license": "MIT",
   "author": {

purview-build.schema.json

@@ -83,6 +83,10 @@
 					"type": "boolean",
 					"default": true
 				},
+				"CSharpierPath": {
+					"type": "string",
+					"description": "Path (relative to the repository root, or absolute) to a CSharpier CLI assembly (a .dll) to run with dotnet instead of the repository\u0027s dotnet-tools.json manifest tool. Use when a repository needs an unreleased CSharpier build (for example C# 15 union support); leave unset to run the manifest tool."
+				},
 				"RunPack": {
 					"type": "boolean",
 					"default": true
@@ -489,4 +493,4 @@
 	"patternProperties": {
 		"^\\$": true
 	}
-}
+}

skills/purview-build-configuration/SKILL.md

@@ -54,6 +54,7 @@ for an environment variable of that name before anything else.
 | `ArtifactsFolder` | `artifacts` | package output directory |
 | `CleanArtifacts` | `true` | delete and recreate `ArtifactsFolder` before anything is produced. Ignored when `RunPack` is `false` |
 | `RunTests` / `RunLint` / `RunPack` / `ValidatePack` | `true` | the per-stage switches |
+| `CSharpierPath` | unset | path (relative to the repository root, or absolute) to a CSharpier CLI `.dll` run with `dotnet` instead of the `dotnet-tools.json` manifest tool, for an unreleased CSharpier build (dotnet only) |
 | `TestRoot` | `src/tests` | discovery root, relative to the repository root |
 | `TestPatterns` | `*Tests.csproj` | comma-separated search patterns under `TestRoot` |
 | `TestProjects` | `*` | comma-separated names/globs to actually run |

skills/purview-build-pipeline/SKILL.md

@@ -96,7 +96,8 @@ Depends on `Restore` — Web lint invokes tooling that `bun install` put there.
 
 - **DotNet** — `dotnet tool restore` (retried up to 3 times with a 2-second backoff), then
   `dotnet tool run csharpier check <repository root>`. The root is resolved by walking up to the
-  nearest `package.json`.
+  nearest `package.json`. When `Build:CSharpierPath` is set, the manifest tool is bypassed: the module
+  runs `dotnet <path> check <repository root>` against the vendored assembly and restores nothing.
 - **Web** — `WebFormatCheckCommand` then `WebLintCommand`, each skipped when the corresponding
   script is not declared in the root `package.json`.
 

src/src/Build/Modules/LintModule.cs

@@ -36,6 +36,17 @@ CancellationToken cancellationToken
 		if (settings.Value.ProjectType == ProjectType.Web)
 			return await RunWebLintAsync(context, repositoryRoot, cancellationToken);
 
+		// A repository that needs an unreleased CSharpier (for example one that formats C# 15 unions)
+		// points CSharpierPath at a CLI assembly it vendors itself. The manifest tool is then bypassed
+		// entirely, so no `dotnet tool restore` is required.
+		if (!string.IsNullOrWhiteSpace(settings.Value.CSharpierPath))
+			return await RunCSharpierAsync(
+				context,
+				repositoryRoot,
+				settings.Value.CSharpierPath,
+				cancellationToken
+			);
+
 		var dotnet = context.DotNet();
 
 		const int maxAttempts = 3;
@@ -65,6 +76,26 @@ Task<CommandResult> Restore() =>
 		);
 	}
 
+	async Task<CommandResult?> RunCSharpierAsync(
+		IModuleContext context,
+		string repositoryRoot,
+		string cSharpierPath,
+		CancellationToken cancellationToken
+	)
+	{
+		var path = Path.IsPathRooted(cSharpierPath)
+			? cSharpierPath
+			: Path.Combine(repositoryRoot, cSharpierPath);
+
+		context.Logger.LogInformation("Running CSharpier from {Path}.", path);
+
+		return await context.Shell.Command.ExecuteCommandLineTool(
+			DotNetCLIOptions.Create(path, "check", repositoryRoot),
+			new() { WorkingDirectory = repositoryRoot },
+			cancellationToken: cancellationToken
+		);
+	}
+
 	async Task<CommandResult?> RunWebLintAsync(
 		IModuleContext context,
 		string repositoryRoot,

src/src/Build/Settings/BuildSettings.cs

@@ -63,6 +63,14 @@ public sealed class BuildSettings
 
 	public bool RunLint { get; init; } = true;
 
+	/// <summary>
+	/// Path (relative to the repository root, or absolute) to a CSharpier CLI assembly (a <c>.dll</c>)
+	/// to run with <c>dotnet</c> instead of the repository's <c>dotnet-tools.json</c> manifest tool.
+	/// Use when a repository needs an unreleased CSharpier build (for example C# 15 union support);
+	/// leave unset to run the manifest tool.
+	/// </summary>
+	public string? CSharpierPath { get; init; }
+
 	public bool RunPack { get; init; } = true;
 
 	public bool ValidatePack { get; init; } = true;

src/src/Build/appsettings.json

@@ -13,6 +13,7 @@
 		"TestFramework": "TUnit",
 		"TestFilter": "/*/*/*/*/",
 		"RunLint": true,
+		"CSharpierPath": null,
 		"RunPack": true,
 		"ValidatePack": true,
 		"WebInstallCommand": "bun install",