replace PackedUserHash with simple PackedUser

passing hashes is OK

src/sections.zig

@@ -251,13 +251,13 @@ pub fn usersSection(
         const userOffset = try math.cast(u32, blob.items.len);
         std.debug.assert(userOffset & 7 == 0);
         idx2offset[i] = userOffset;
-        try userImport.PackedUserHash.packTo(
+        try userImport.PackedUser.packTo(
             &blob,
             user,
             gids.idx2offset[i],
             shells.indices,
         );
-        try pad.arrayList(&blob, userImport.PackedUserHash.alignment_bits);
+        try pad.arrayList(&blob, userImport.PackedUser.alignment_bits);
     }
     return UsersSection{
         .idx2offset = idx2offset,

src/user.zig

@@ -10,6 +10,7 @@ const mem = std.mem;
 const math = std.math;
 const Allocator = mem.Allocator;
 const ArrayList = std.ArrayList;
+const StringHashMap = std.StringHashMap;
 
 // Idx2ShellProto is a function prototype that, given a shell's index (in
 // global shell section), will return a shell string. Matches ShellReader.get.
@@ -78,10 +79,7 @@ pub fn Shell2Index(T: type) type {
     };
 }
 
-pub const PackedUserHash = packedUser(std.StringHashMap(u6));
-
-fn packedUser(comptime ShellIndexType: type) type {
-    return struct {
+pub const PackedUser = struct {
     const Self = @This();
 
     pub const alignment_bits = 3;
@@ -205,7 +203,7 @@ fn packedUser(comptime ShellIndexType: type) type {
         arr: *ArrayList(u8),
         user: User,
         additional_gids_offset: u64,
-            idxFn: ShellIndexType,
+        idxFn: StringHashMap(u6),
     ) error{ InvalidRecord, OutOfMemory }!void {
         std.debug.assert(arr.items.len & 7 == 0);
         // function arguments are consts. We need to mutate the underlying
@@ -279,30 +277,23 @@ fn packedUser(comptime ShellIndexType: type) type {
         }
         return idxFn(self.inner.shell_len_or_idx);
     }
-    };
-}
+};
 
 const testing = std.testing;
 
 test "PackedUser internal and external alignment" {
     try testing.expectEqual(
-        @sizeOf(PackedUserHash.Inner) * 8,
-        @bitSizeOf(PackedUserHash.Inner),
+        @sizeOf(PackedUser.Inner) * 8,
+        @bitSizeOf(PackedUser.Inner),
     );
 }
 
-const TestShellIndex = struct {
-    pub fn get(_: *const TestShellIndex, shell: []const u8) ?u6 {
-        if (mem.eql(u8, shell, "/bin/bash")) {
-            return 0;
-        } else if (mem.eql(u8, shell, "/bin/zsh")) {
-            return 1;
-        }
-        return null;
-    }
-};
-
-const PackedUserTest = packedUser(TestShellIndex);
+fn testShellIndex(allocator: Allocator) StringHashMap(u6) {
+    var result = StringHashMap(u6).init(allocator);
+    result.put("/bin/bash", 0) catch unreachable;
+    result.put("/bin/zsh", 1) catch unreachable;
+    return result;
+}
 
 fn testShell(index: u6) []const u8 {
     return switch (index) {
@@ -345,13 +336,15 @@ test "construct PackedUser section" {
         .home = "/",
         .shell = "/",
     } };
+    var shellIndex = testShellIndex(testing.allocator);
+    defer shellIndex.deinit();
     for (users) |user| {
-        try PackedUserTest.packTo(&buf, user, math.maxInt(u64), TestShellIndex{});
-        try pad.arrayList(&buf, PackedUserHash.alignment_bits);
+        try PackedUser.packTo(&buf, user, math.maxInt(u64), shellIndex);
+        try pad.arrayList(&buf, PackedUser.alignment_bits);
     }
 
     var i: u29 = 0;
-    var it1 = PackedUserTest.iterator(buf.items, testShell);
+    var it1 = PackedUser.iterator(buf.items, testShell);
     while (try it1.next()) |user| : (i += 1) {
         try testing.expectEqual(users[i].uid, user.uid());
         try testing.expectEqual(users[i].gid, user.gid());