feat!: SDL2 provisioning leaves the core for the sdl2 provider (cli#471 S4)

docs/provider-contract-v1.md

@@ -122,7 +122,7 @@ A `before generate`, `after generate` or `before build` hook receives `env_file`
 
 **Freshness.** The environment is built for each build from the inherited environment plus the contributions of the hooks that ran in that build; a watched rebuild starts over. A hook a replan removed leaves nothing behind. A watched rebuild that fails, at any stage, keeps the environment of the last successful build (the one being served, and the one the session's `after run` hooks get); only a rebuild that succeeds replaces it.
 
-**Scope.** The merged environment reaches every later zig invocation and hook process of the same command: the generation-time fingerprint pass (`zig build --list-steps`, which configures the generated build and so is the first toolchain consumer: a `before generate` contribution reaches it, an `after generate` one does not), the core `zig build` compile, and every later hook and replacement (`after generate`, `before`/`replace`/`after build`, `bundle` and `run` hooks). It never reaches the build of a provider's own tool (`zig build <build_step>` in the provider's package), which runs on the plain inherited environment plus the CLI's cache variables, so a provider cannot change how other providers' tools are built. The game the core `labelle run` launches keeps its own environment (the inherited one plus the run options); a provider that must reach the game uses a `run` replacement. The runtime `SDL2.dll` the core stages beside a desktop exe is looked up through `LABELLE_SDL2_LIB` as the compile saw it, so a contributed value is honoured.
+**Scope.** The merged environment reaches every later zig invocation and hook process of the same command: the generation-time fingerprint pass (`zig build --list-steps`, which configures the generated build and so is the first toolchain consumer: a `before generate` contribution reaches it, an `after generate` one does not), the core `zig build` compile, and every later hook and replacement (`after generate`, `before`/`replace`/`after build`, `bundle` and `run` hooks). It never reaches the build of a provider's own tool (`zig build <build_step>` in the provider's package), which runs on the plain inherited environment plus the CLI's cache variables, so a provider cannot change how other providers' tools are built. The game the core `labelle run` launches keeps its own environment (the inherited one plus the run options); a provider that must reach the game uses a `run` replacement. The core stages no runtime library beside a built exe: it only merges the contribution into the environment above. Staging one (a DLL next to a desktop exe, say) is a provider's job, in an `after build` hook, which sees the merged environment as the compile did; the `sdl2` provider's `stage` hook copies `SDL2.dll` this way (cli#471 S4).
 
 **No silent bypass.** A build path that cannot carry a provider's contribution or its optimize default refuses before any hook, generation or build, naming the hook or package. `--docker` builds in a container the contributions never reach, so a `build`, `run` or `bundle` (any command that reaches the container build) whose plan has a hook that may contribute (one in a contributing slot whose provider negotiates `1.3.0` or newer) is refused; `labelle generate --docker` is not, since it stops after generation and its host-side fingerprint pass gets the contributions, and neither is a build the target owner replaces, since its `replace build` hook gets them like every hook: `--docker doesn't carry provider environment contributions; build without --docker`. (`--docker` does pass the effective optimize mode as `-Doptimize`.) The legacy `labelle ios` subcommand runs its own `zig build` after generation, with neither, so it is refused when the plan has such a hook or the target's owner declares an optimize default; `labelle build --platform=ios` carries both.
 

src/agnostic_guard_test.zig

@@ -111,7 +111,10 @@ const allowed_words = [_][]const u8{ "macos", "windows", "linux", "darwin", "win
 /// the target dir, and `upgrade all` delegates the backend pin to
 /// `labelle-assembler upgrade backend`), so `cli/upgrade.zig` came clean,
 /// and `cli/pipeline/generate.zig` once its comments stopped citing
-/// backend and platform names: 14 entries.
+/// backend and platform names: 14 entries. RFC cli#471 S4 moved SDL2
+/// provisioning, runtime DLL staging and the doctor rows to the opt-in
+/// `sdl2` provider (labelle-sdl), deleting `cli/sdl_provision.zig`:
+/// 13 entries.
 /// Shrink only: an entry whose file is clean fails the test until it is
 /// removed. Note the path scan: an entry
 /// under `cli/android/` or named `cli/ios.zig` stays dirty until the file is
@@ -134,7 +137,6 @@ const allowed_files = [_][]const u8{
     "cli/pipeline/run.zig",
     "cli/project_config.zig",
     "cli/provider_dispatch.zig",
-    "cli/sdl_provision.zig",
 };
 
 const finding_note = "(platform/store/package names belong in providers; see docs/rfc-package-commands.md#enforcement)";
@@ -600,13 +602,12 @@ test "a platform in the path is a finding, and keeps an allowlist entry dirty" {
     // An allowlisted file whose path names a platform stays dirty with
     // clean contents: the entry is only stale once the file is moved or
     // renamed.
-    try scan.file("cli/sdl_provision.zig", "const x = 1;\n");
+    try scan.file("cli/ios.zig", "const x = 1;\n");
     try scan.file("cli\\ios.zig", "");
     try std.testing.expectEqual(@as(usize, 7), scan.offenders.items.len);
     var stale: std.ArrayList([]const u8) = .empty;
     defer stale.deinit(gpa);
     try scan.stale(&stale);
-    try std.testing.expect(!containsString(stale.items, "cli/sdl_provision.zig"));
     try std.testing.expect(!containsString(stale.items, "cli/ios.zig"));
     try std.testing.expect(containsString(stale.items, "cli/project_config.zig"));
 }

src/cli.zig

@@ -53,7 +53,6 @@ const provider_contract = @import("cli/provider_contract.zig");
 const provider_github = @import("cli/provider_github.zig");
 const provider_targets = @import("cli/provider_targets.zig");
 const doctor = @import("cli/doctor.zig");
-const sdl_provision = @import("cli/sdl_provision.zig");
 
 // Argument parsing lives in cli/args.zig (extracted so neither file
 // exceeds ~1000 lines). Alias the decls main/dispatch reference so their

src/cli/config.zig

@@ -274,10 +274,6 @@ pub const reserved_env = [_][]const u8{
 /// with the reason it is not CLI-owned. Kept beside `reserved_env` so the
 /// guard can tell a deliberate decision from a forgotten name.
 pub const unreserved_labelle_env = [_][]const u8{
-    // The SDL2 library directory. The CLI reads it only to find a user's
-    // install; a package that provisions SDL2 is meant to set it for the
-    // build (RFC cli#466 §9).
-    "LABELLE_SDL2_LIB",
     // Written into a bundle's launcher script for the game; never read by
     // the CLI.
     "LABELLE_DATA_DIR",
@@ -297,17 +293,17 @@ test "provider env reserved names: a fixed CLI-owned table, case-folded under Wi
         try std.testing.expect(reservedEnvName(name, false));
         try std.testing.expect(reservedEnvName(name, true));
     }
-    // Not a prefix ban: the SDL2 library variable and any other name stay
-    // settable, and an env_file setting it parses.
-    for ([_][]const u8{ "LABELLE_SDL2_LIB", "LABELLE_ANYTHING", "TOOLCHAIN_ROOT" }) |name| {
+    // Not a prefix ban: a provider's own `LABELLE_*` variable and any other
+    // name stay settable, and an env_file setting one parses.
+    for ([_][]const u8{ "LABELLE_ANYTHING", "TOOLCHAIN_ROOT" }) |name| {
         try std.testing.expect(!reservedEnvName(name, false));
         try std.testing.expect(!reservedEnvName(name, true));
     }
     var arena = std.heap.ArenaAllocator.init(std.testing.allocator);
     defer arena.deinit();
     var diag: @import("provider_env.zig").Diagnostic = .{};
-    const file = try @import("provider_env.zig").parseFile(arena.allocator(), "{\"set\":[{\"name\":\"LABELLE_SDL2_LIB\",\"value\":\"/sdl/lib\"}]}", false, &diag);
-    try std.testing.expectEqualStrings("LABELLE_SDL2_LIB", file.set[0].name);
+    const file = try @import("provider_env.zig").parseFile(arena.allocator(), "{\"set\":[{\"name\":\"LABELLE_ANYTHING\",\"value\":\"/opt/lib\"}]}", false, &diag);
+    try std.testing.expectEqualStrings("LABELLE_ANYTHING", file.set[0].name);
     // `Path` is PATH under Windows rules only.
     try std.testing.expect(reservedEnvName("Path", true));
     try std.testing.expect(!reservedEnvName("Path", false));