build: delete module_homes — imports resolve through the declared zon

The module-to-domain table in build-support duplicated what each
domain's build.zig already states with its addModule exports. userBinary
now resolves each named import by searching the packages the binary
declared in its own build.zig.zon (b.available_deps), which also makes
the zon the literal include path: an import can only be satisfied by a
domain the binary claims, and naming a module whose domain is missing
fails the build graph with the domain to declare. build-support is down
to the recipe alone. All build variants green; manifest unchanged.

build-support/build.zig

@@ -31,60 +31,20 @@ pub fn freestandingTarget(b: *std.Build) std.Build.ResolvedTarget {
     });
 }
 
-/// Which library domain package exports each importable module — the one
+/// Resolve one imported module by searching the packages this binary DECLARED
-/// name -> home table. When a domain grows a module, it gets a row here; a
+/// in its own build.zig.zon — the C include path made literal: an import can
-/// binary naming a module whose home is missing from its own build.zig.zon
+/// only be satisfied by a domain the binary claims, and each domain's own
-/// fails loudly at dependency resolution.
+/// build.zig (its addModule exports) is the single statement of who owns
-const ModuleHome = struct { name: []const u8, home: []const u8 };
+/// what. There is no name table here to drift.
-const module_homes = [_]ModuleHome{
+fn moduleFromDeclaredDependencies(b: *std.Build, name: []const u8) *std.Build.Module {
-    // library/kernel — the userspace private-ABI library, split by concern.
+    for (b.available_deps) |declared| {
-    .{ .name = "abi", .home = "kernel" },
+        const dependency = b.dependency(declared[0], .{});
-    .{ .name = "system-call", .home = "kernel" },
+        if (dependency.builder.modules.get(name)) |module| return module;
-    .{ .name = "ipc", .home = "kernel" },
-    .{ .name = "time", .home = "kernel" },
-    .{ .name = "thread", .home = "kernel" },
-    .{ .name = "logging", .home = "kernel" },
-    .{ .name = "process", .home = "kernel" },
-    .{ .name = "file-system", .home = "kernel" },
-    .{ .name = "memory", .home = "kernel" },
-    .{ .name = "service", .home = "kernel" },
-    .{ .name = "start", .home = "kernel" },
-    // library/device — driver-side libraries + the flat reference data.
-    .{ .name = "mmio", .home = "device" },
-    .{ .name = "acpi-ids", .home = "device" },
-    .{ .name = "device-abi", .home = "device" },
-    .{ .name = "aml", .home = "device" },
-    .{ .name = "usb-abi", .home = "device" },
-    .{ .name = "usb-ids", .home = "device" },
-    .{ .name = "usb", .home = "device" },
-    .{ .name = "driver", .home = "device" },
-    .{ .name = "block", .home = "device" },
-    .{ .name = "pci", .home = "device" },
-    .{ .name = "pci-class", .home = "device" },
-    .{ .name = "device-registry", .home = "device" },
-    // library/client — userspace service clients.
-    .{ .name = "display-client", .home = "client" },
-    .{ .name = "input-client", .home = "client" },
-    // library/protocol — the wire protocols.
-    .{ .name = "vfs-protocol", .home = "protocol" },
-    .{ .name = "input-protocol", .home = "protocol" },
-    .{ .name = "block-protocol", .home = "protocol" },
-    .{ .name = "usb-transfer-protocol", .home = "protocol" },
-    .{ .name = "device-manager-protocol", .home = "protocol" },
-    .{ .name = "display-protocol", .home = "protocol" },
-    .{ .name = "scanout-protocol", .home = "protocol" },
-    .{ .name = "power-protocol", .home = "protocol" },
-    // library/csv — the /etc/*.csv helpers.
-    .{ .name = "csv", .home = "csv" },
-    // library/xkeyboard-config — keycode -> keysym/character tables.
-    .{ .name = "xkeyboard-config", .home = "xkeyboard-config" },
-};
-
-fn moduleHome(name: []const u8) ?[]const u8 {
-    for (module_homes) |entry| {
-        if (std.mem.eql(u8, entry.name, name)) return entry.home;
     }
-    return null;
+    @panic(b.fmt(
+        "no declared dependency exports a module named '{s}' — declare the domain that owns it in this package's build.zig.zon",
+        .{name},
+    ));
 }
 
 /// What `userBinary` needs to know about one user binary.
@@ -95,8 +55,8 @@ pub const UserBinaryOptions = struct {
     root_source_file: std.Build.LazyPath,
     /// Exactly the modules the program's source @imports (directly or through
     /// its same-directory files) — no more, no less. Order is free; sorted
-    /// reads best. An undeclared @import fails the compile; a declared name no
+    /// reads best. An undeclared @import fails the compile; a name no
-    /// domain exports fails the build graph with a pointer to module_homes.
+    /// declared domain exports fails the build graph, naming the miss.
     imports: []const []const u8,
     /// Built multi-threaded (`single_threaded = false`) so real atomics/TLS
     /// work — required before a binary may call `Thread.spawn`
@@ -121,12 +81,10 @@ pub fn userBinary(b: *std.Build, options: UserBinaryOptions) *std.Build.Step.Com
     const kernel = b.dependency("kernel", .{});
     var imports: std.ArrayListUnmanaged(std.Build.Module.Import) = .empty;
     for (options.imports) |name| {
-        const home = moduleHome(name) orelse @panic(b.fmt(
+        imports.append(b.allocator, .{
-            "no library domain exports a module named '{s}' — if a domain grew it, add its row to module_homes in build-support/build.zig",
+            .name = name,
-            .{name},
+            .module = moduleFromDeclaredDependencies(b, name),
-        ));
+        }) catch @panic("OOM");
-        const dependency = if (std.mem.eql(u8, home, "kernel")) kernel else b.dependency(home, .{});
-        imports.append(b.allocator, .{ .name = name, .module = dependency.module(name) }) catch @panic("OOM");
     }
     // Settings (target, optimize, code model, ...) live on the root module
     // only; the program module inherits them.

docs/build-packages-plan.md

@@ -62,8 +62,10 @@ Rules:
   include list — and its zon names only the domains those modules come from
   (plus `build-support` and `kernel`, which is implicit in every binary: the
   root shim and user link script live there). Nothing is pre-wired: an
-  undeclared `@import` is a compile error, and build-support's one
+  undeclared `@import` is a compile error, and build-support resolves each
-  module-to-domain table (`module_homes`) resolves each name. Availability
+  name by searching the packages the zon declares — the domains' own
+  addModule exports are the single statement of who owns what, with no name
+  table anywhere to drift. Availability
   never meant bloat — Zig only compiles what a program actually imports — but
   exactness makes the declared interface honest and machine-checked.
 - **Modules export source, not artifacts** — each consumer compiles libraries
@@ -132,9 +134,9 @@ rewritten against the package template.
 ## Execution notes (the finished shape)
 
 - The shared recipe lives in `build-support/build.zig`: `userBinary` (what
-  every binary package calls, resolving each named import through the
+  every binary package calls; each named import resolves by searching the
-  `module_homes` table) and `programModule` (for per-binary addOptions
+  packages the binary's zon declares) and `programModule` (for per-binary
-  modules). The `start` root shim and `user.ld` are named through the kernel
+  addOptions modules). The `start` root shim and `user.ld` are named through the kernel
   package (Dependency.path).
 - Adding a binary = adding a directory with source + a ~15-line build.zig +
   zon (copy any existing binary package, e.g.

system/drivers/pci-bus/build.zig

@@ -1,6 +1,6 @@
 //! The pci-bus driver as a binary package (docs/build-packages-plan.md):
 //! this file names the binary and EXACTLY the modules its source imports —
-//! the shared recipe and the module-to-domain map live in build-support.
+//! build-support resolves each name from the domains this zon declares.
 
 const std = @import("std");
 const build_support = @import("build-support");

system/drivers/ps2-bus/build.zig

@@ -1,6 +1,6 @@
 //! The ps2-bus driver as a binary package (docs/build-packages-plan.md):
 //! this file names the binary and EXACTLY the modules its source imports —
-//! the shared recipe and the module-to-domain map live in build-support.
+//! build-support resolves each name from the domains this zon declares.
 
 const std = @import("std");
 const build_support = @import("build-support");

system/drivers/usb-hid/build.zig

@@ -1,6 +1,6 @@
 //! The usb-hid driver as a binary package (docs/build-packages-plan.md):
 //! this file names the binary and EXACTLY the modules its source imports —
-//! the shared recipe and the module-to-domain map live in build-support.
+//! build-support resolves each name from the domains this zon declares.
 
 const std = @import("std");
 const build_support = @import("build-support");

system/drivers/usb-storage/build.zig

@@ -1,6 +1,6 @@
 //! The usb-storage driver as a binary package (docs/build-packages-plan.md):
 //! this file names the binary and EXACTLY the modules its source imports —
-//! the shared recipe and the module-to-domain map live in build-support.
+//! build-support resolves each name from the domains this zon declares.
 
 const std = @import("std");
 const build_support = @import("build-support");

system/drivers/usb-xhci-bus/build.zig

@@ -1,6 +1,6 @@
 //! The usb-xhci-bus driver as a binary package (docs/build-packages-plan.md):
 //! this file names the binary and EXACTLY the modules its source imports —
-//! the shared recipe and the module-to-domain map live in build-support.
+//! build-support resolves each name from the domains this zon declares.
 
 const std = @import("std");
 const build_support = @import("build-support");

system/drivers/virtio-gpu/build.zig

@@ -1,6 +1,6 @@
 //! The virtio-gpu driver as a binary package (docs/build-packages-plan.md):
 //! this file names the binary and EXACTLY the modules its source imports —
-//! the shared recipe and the module-to-domain map live in build-support.
+//! build-support resolves each name from the domains this zon declares.
 
 const std = @import("std");
 const build_support = @import("build-support");

system/services/acpi/build.zig

@@ -1,6 +1,6 @@
 //! The acpi service as a binary package (docs/build-packages-plan.md):
 //! this file names the binary and EXACTLY the modules its source imports —
-//! the shared recipe and the module-to-domain map live in build-support.
+//! build-support resolves each name from the domains this zon declares.
 //!
 //! The artifact is named "discovery": one swappable process per firmware
 //! fills the ramdisk's neutral `discovery` slot (docs/discovery.md); the

system/services/device-manager/build.zig

@@ -1,6 +1,6 @@
 //! The device-manager service as a binary package (docs/build-packages-plan.md):
 //! this file names the binary and EXACTLY the modules its source imports —
-//! the shared recipe and the module-to-domain map live in build-support.
+//! build-support resolves each name from the domains this zon declares.
 
 const std = @import("std");
 const build_support = @import("build-support");

system/services/display-demo/build.zig

@@ -1,6 +1,6 @@
 //! The display-demo service as a binary package (docs/build-packages-plan.md):
 //! this file names the binary and EXACTLY the modules its source imports —
-//! the shared recipe and the module-to-domain map live in build-support.
+//! build-support resolves each name from the domains this zon declares.
 
 const std = @import("std");
 const build_support = @import("build-support");

system/services/display/build.zig

@@ -1,6 +1,6 @@
 //! The display service as a binary package (docs/build-packages-plan.md):
 //! this file names the binary and EXACTLY the modules its source imports —
-//! the shared recipe and the module-to-domain map live in build-support.
+//! build-support resolves each name from the domains this zon declares.
 
 const std = @import("std");
 const build_support = @import("build-support");

system/services/fat/build.zig

@@ -1,6 +1,6 @@
 //! The fat service as a binary package (docs/build-packages-plan.md):
 //! this file names the binary and EXACTLY the modules its source imports —
-//! the shared recipe and the module-to-domain map live in build-support.
+//! build-support resolves each name from the domains this zon declares.
 
 const std = @import("std");
 const build_support = @import("build-support");

system/services/fdt/build.zig

@@ -1,6 +1,6 @@
 //! The fdt service as a binary package (docs/build-packages-plan.md):
 //! this file names the binary and EXACTLY the modules its source imports —
-//! the shared recipe and the module-to-domain map live in build-support.
+//! build-support resolves each name from the domains this zon declares.
 //!
 //! The artifact is named "discovery" like acpi's: the Raspberry Pis hand over
 //! a flattened device tree, and the aarch64 target flips the root's

system/services/init/build.zig

@@ -1,6 +1,6 @@
 //! init (PID 1) as a binary package (docs/build-packages-plan.md): this file
 //! names the binary and EXACTLY the modules its source imports — the shared
-//! recipe and the module-to-domain map live in build-support. The root build
+//! recipe resolves each name from the domains the zon declares. The root build
 //! consumes the artifact for the boot image and forwards its -Dserial here.
 
 const std = @import("std");

system/services/input/build.zig

@@ -1,6 +1,6 @@
 //! The input service as a binary package (docs/build-packages-plan.md):
 //! this file names the binary and EXACTLY the modules its source imports —
-//! the shared recipe and the module-to-domain map live in build-support.
+//! build-support resolves each name from the domains this zon declares.
 
 const std = @import("std");
 const build_support = @import("build-support");

test/system/services/args-echo/build.zig

@@ -1,6 +1,6 @@
 //! The args-echo test fixture as a binary package (docs/build-packages-plan.md):
 //! this file names the binary and EXACTLY the modules its source imports —
-//! the shared recipe and the module-to-domain map live in build-support.
+//! build-support resolves each name from the domains this zon declares.
 
 const std = @import("std");
 const build_support = @import("build-support");

test/system/services/crash-test/build.zig

@@ -1,6 +1,6 @@
 //! The crash-test test fixture as a binary package (docs/build-packages-plan.md):
 //! this file names the binary and EXACTLY the modules its source imports —
-//! the shared recipe and the module-to-domain map live in build-support.
+//! build-support resolves each name from the domains this zon declares.
 
 const std = @import("std");
 const build_support = @import("build-support");

test/system/services/device-list/build.zig

@@ -1,6 +1,6 @@
 //! The device-list test fixture as a binary package (docs/build-packages-plan.md):
 //! this file names the binary and EXACTLY the modules its source imports —
-//! the shared recipe and the module-to-domain map live in build-support.
+//! build-support resolves each name from the domains this zon declares.
 
 const std = @import("std");
 const build_support = @import("build-support");

test/system/services/fat-test/build.zig

@@ -1,6 +1,6 @@
 //! The fat-test test fixture as a binary package (docs/build-packages-plan.md):
 //! this file names the binary and EXACTLY the modules its source imports —
-//! the shared recipe and the module-to-domain map live in build-support.
+//! build-support resolves each name from the domains this zon declares.
 
 const std = @import("std");
 const build_support = @import("build-support");

test/system/services/input-source/build.zig

@@ -1,6 +1,6 @@
 //! The input-source test fixture as a binary package (docs/build-packages-plan.md):
 //! this file names the binary and EXACTLY the modules its source imports —
-//! the shared recipe and the module-to-domain map live in build-support.
+//! build-support resolves each name from the domains this zon declares.
 
 const std = @import("std");
 const build_support = @import("build-support");

test/system/services/input-test/build.zig

@@ -1,6 +1,6 @@
 //! The input-test test fixture as a binary package (docs/build-packages-plan.md):
 //! this file names the binary and EXACTLY the modules its source imports —
-//! the shared recipe and the module-to-domain map live in build-support.
+//! build-support resolves each name from the domains this zon declares.
 
 const std = @import("std");
 const build_support = @import("build-support");

test/system/services/iommu-fault-test/build.zig

@@ -1,6 +1,6 @@
 //! The iommu-fault-test test fixture as a binary package (docs/build-packages-plan.md):
 //! this file names the binary and EXACTLY the modules its source imports —
-//! the shared recipe and the module-to-domain map live in build-support.
+//! build-support resolves each name from the domains this zon declares.
 
 const std = @import("std");
 const build_support = @import("build-support");

test/system/services/pci-cap-test/build.zig

@@ -1,6 +1,6 @@
 //! The pci-cap-test test fixture as a binary package (docs/build-packages-plan.md):
 //! this file names the binary and EXACTLY the modules its source imports —
-//! the shared recipe and the module-to-domain map live in build-support.
+//! build-support resolves each name from the domains this zon declares.
 
 const std = @import("std");
 const build_support = @import("build-support");

test/system/services/process-test/build.zig

@@ -1,6 +1,6 @@
 //! The process-test test fixture as a binary package (docs/build-packages-plan.md):
 //! this file names the binary and EXACTLY the modules its source imports —
-//! the shared recipe and the module-to-domain map live in build-support.
+//! build-support resolves each name from the domains this zon declares.
 
 const std = @import("std");
 const build_support = @import("build-support");

test/system/services/shared-memory-client/build.zig

@@ -1,6 +1,6 @@
 //! The shared-memory-client test fixture as a binary package (docs/build-packages-plan.md):
 //! this file names the binary and EXACTLY the modules its source imports —
-//! the shared recipe and the module-to-domain map live in build-support.
+//! build-support resolves each name from the domains this zon declares.
 
 const std = @import("std");
 const build_support = @import("build-support");

test/system/services/shared-memory-server/build.zig

@@ -1,6 +1,6 @@
 //! The shared-memory-server test fixture as a binary package (docs/build-packages-plan.md):
 //! this file names the binary and EXACTLY the modules its source imports —
-//! the shared recipe and the module-to-domain map live in build-support.
+//! build-support resolves each name from the domains this zon declares.
 
 const std = @import("std");
 const build_support = @import("build-support");

test/system/services/thread-test/build.zig

@@ -1,6 +1,6 @@
 //! The thread-test test fixture as a binary package (docs/build-packages-plan.md):
 //! this file names the binary and EXACTLY the modules its source imports —
-//! the shared recipe and the module-to-domain map live in build-support.
+//! build-support resolves each name from the domains this zon declares.
 
 const std = @import("std");
 const build_support = @import("build-support");

test/system/services/vfs-test/build.zig

@@ -1,6 +1,6 @@
 //! The vfs-test test fixture as a binary package (docs/build-packages-plan.md):
 //! this file names the binary and EXACTLY the modules its source imports —
-//! the shared recipe and the module-to-domain map live in build-support.
+//! build-support resolves each name from the domains this zon declares.
 
 const std = @import("std");
 const build_support = @import("build-support");