Added custom build runner, install it along with the zls binary

build.zig

@@ -29,10 +29,14 @@ pub fn build(b: *std.build.Builder) !void {
         b.option(bool, "allocation_info", "Enable use of debugging allocator and info logging.") orelse false,
     );
 
+    exe.addPackage(.{ .name = "known-folders", .path = "src/known-folders/known-folders.zig" });
+
     exe.setTarget(target);
     exe.setBuildMode(mode);
     exe.install();
 
+    b.installFile("src/special/build_runner.zig", "bin/build_runner.zig");
+
     const run_cmd = exe.run();
     run_cmd.step.dependOn(b.getInstallStep());
 

src/main.zig

@@ -870,7 +870,7 @@ pub fn main() anyerror!void {
     defer std.json.parseFree(Config, config, config_parse_options);
 
     config_read: {
-        const known_folders = @import("known-folders/known-folders.zig");
+        const known_folders = @import("known-folders");
         const res = try known_folders.getPath(allocator, .local_configuration);
         if (res) |local_config_path| {
             defer allocator.free(local_config_path);

src/special/build_runner.zig

@@ -0,0 +1,89 @@
+const root = @import("build.zig");
+const std = @import("std");
+const io = std.io;
+const fmt = std.fmt;
+const Builder = std.build.Builder;
+const Pkg = std.build.Pkg;
+const LibExeObjStep = std.build.LibExeObjStep;
+const ArrayList = std.ArrayList;
+///! This is a modified build runner to extract information out of build.zig
+///! Modified from std.special.build_runner
+
+// We use a custom Allocator to intercept the creation of steps
+const InterceptAllocator = struct {
+    base_allocator: *std.mem.Allocator,
+    allocator: std.mem.Allocator,
+    steps: std.ArrayListUnmanaged(*LibExeObjStep),
+
+    fn init(base_allocator: *std.mem.Allocator) InterceptAllocator {
+        return .{
+            .base_allocator = base_allocator,
+            .allocator = .{
+                .reallocFn = realloc,
+                .shrinkFn = shrink,
+            },
+            .steps = .{},
+        };
+    }
+
+    // TODO: Check LibExeObjStep has a unique size.
+    fn realloc(allocator: *std.mem.Allocator, old_mem: []u8, old_align: u29, new_size: usize, new_align: u29) ![]u8 {
+        const self = @fieldParentPtr(InterceptAllocator, "allocator", allocator);
+        var data = try self.base_allocator.reallocFn(self.base_allocator, old_mem, old_align, new_size, new_align);
+        if (old_mem.len == 0 and new_size == @sizeOf(LibExeObjStep)) {
+            try self.steps.append(self.base_allocator, @ptrCast(*LibExeObjStep, @alignCast(@alignOf(LibExeObjStep), data.ptr)));
+        }
+        return data;
+    }
+
+    fn shrink(allocator: *std.mem.Allocator, old_mem: []u8, old_align: u29, new_size: usize, new_align: u29) []u8 {
+        const self = @fieldParentPtr(InterceptAllocator, "allocator", allocator);
+        return self.base_allocator.shrinkFn(self.base_allocator, old_mem, old_align, new_size, new_align);
+    }
+
+    fn deinit(self: *InterceptAllocator) void {
+        self.steps.deinit(self.base_allocator);
+    }
+};
+
+pub fn main() !void {
+    var arena = std.heap.ArenaAllocator.init(std.heap.page_allocator);
+    defer arena.deinit();
+
+    var intercept = InterceptAllocator.init(&arena.allocator);
+    defer intercept.deinit();
+    const allocator = &intercept.allocator;
+
+    const builder = try Builder.create(allocator, "", "", "");
+    defer builder.destroy();
+
+    try runBuild(builder);
+
+    const stdout_stream = io.getStdOut().outStream();
+
+    // TODO: We currently add packages from every step.,
+    //       Should we error out or keep one step or something similar?
+    // We also flatten them, we should probably keep the nested structure.
+    for (intercept.steps.items) |step| {
+        for (step.packages.items) |pkg| {
+            try processPackage(stdout_stream, pkg);
+        }
+    }
+}
+
+fn processPackage(out_stream: var, pkg: Pkg) anyerror!void {
+    try out_stream.print("{}\x00{}\n", .{ pkg.name, pkg.path });
+    if (pkg.dependencies) |dependencies| {
+        for (dependencies) |dep| {
+            try processPackage(out_stream, dep);
+        }
+    }
+}
+
+fn runBuild(builder: *Builder) anyerror!void {
+    switch (@typeInfo(@TypeOf(root.build).ReturnType)) {
+        .Void => root.build(builder),
+        .ErrorUnion => try root.build(builder),
+        else => @compileError("expected return type of build to be 'void' or '!void'"),
+    }
+}