Use WASI preopens to lookup Zig lib directory for analysis tests

Author: FnControlOption

src/Server.zig

@@ -1379,7 +1379,7 @@ fn resolveConfiguration(
 
     if (config.zig_lib_path) |zig_lib_path| blk: {
         if (zig_builtin.target.os.tag == .wasi) {
-            std.log.warn("The 'zig_lib_path' config option is ignored on WASI in favor of preopens.", .{});
+            log.warn("The 'zig_lib_path' config option is ignored on WASI in favor of preopens.", .{});
             break :blk;
         }
         if (std.fs.openDirAbsolute(zig_lib_path, .{})) |zig_lib_dir| {
@@ -1408,7 +1408,7 @@ fn resolveConfiguration(
 
     if (config.global_cache_path) |global_cache_path| blk: {
         if (zig_builtin.target.os.tag == .wasi) {
-            std.log.warn("The 'global_cache_path' config option is ignored on WASI in favor of preopens.", .{});
+            log.warn("The 'global_cache_path' config option is ignored on WASI in favor of preopens.", .{});
             break :blk;
         }
         if (std.fs.cwd().makeOpenPath(global_cache_path, .{})) |global_cache_dir| {

tests/analysis_check.zig

@@ -63,6 +63,10 @@ pub fn main() Error!void {
             };
             config.zig_exe_path = try arena.dupe(u8, zig_exe_path);
         } else if (std.mem.eql(u8, arg, "--zig-lib-path")) {
+            if (builtin.target.os.tag == .wasi) {
+                std.log.warn("The 'zig_lib_path' config option is ignored on WASI in favor of preopens.", .{});
+                continue;
+            }
             const zig_lib_path = arg_it.next() orelse {
                 std.log.err("expected argument after '--zig-lib-path'.", .{});
                 std.process.exit(1);
@@ -83,6 +87,20 @@ pub fn main() Error!void {
         }
     }
 
+    if (builtin.target.os.tag == .wasi) {
+        const wasi_preopens = try std.fs.wasi.preopensAlloc(gpa);
+        defer {
+            for (wasi_preopens.names[3..]) |name| gpa.free(name);
+            gpa.free(wasi_preopens.names);
+        }
+
+        const zig_lib_dir_fd = wasi_preopens.find("/lib") orelse {
+            std.log.err("failed to resolve '/lib' WASI preopen", .{});
+            std.process.exit(1);
+        };
+        config.zig_lib_dir = .{ .handle = .{ .fd = zig_lib_dir_fd }, .path = "/lib" };
+    }
+
     var thread_pool: if (builtin.single_threaded) void else std.Thread.Pool = undefined;
     if (builtin.single_threaded) {
         thread_pool = {};