From e52cc47341d7936e40e46e221c7bb281421b4d57 Mon Sep 17 00:00:00 2001
From: IOKG04 <iokg04@gmail.com>
Date: Fri, 19 Sep 2025 13:05:01 +0200
Subject: [PATCH 1/2] `orderSentinel` instead of `orderZ`

---
 lib/c/string.zig           |  2 +-
 lib/std/mem.zig            | 30 ++++++++++++++++++++++++++----
 lib/std/zig/c_builtins.zig |  2 +-
 3 files changed, 28 insertions(+), 6 deletions(-)

diff --git a/lib/c/string.zig b/lib/c/string.zig
index a644093af57e..a24cb633b2f2 100644
--- a/lib/c/string.zig
+++ b/lib/c/string.zig
@@ -15,7 +15,7 @@ comptime {
 
 fn strcmp(s1: [*:0]const c_char, s2: [*:0]const c_char) callconv(.c) c_int {
     // We need to perform unsigned comparisons.
-    return switch (std.mem.orderZ(u8, @ptrCast(s1), @ptrCast(s2))) {
+    return switch (std.mem.orderSentinel(u8, 0, @ptrCast(s1), @ptrCast(s2))) {
         .lt => -1,
         .eq => 0,
         .gt => 1,
diff --git a/lib/std/mem.zig b/lib/std/mem.zig
index 128ac695cff7..0036c3bda257 100644
--- a/lib/std/mem.zig
+++ b/lib/std/mem.zig
@@ -658,11 +658,21 @@ pub fn order(comptime T: type, lhs: []const T, rhs: []const T) math.Order {
     return math.order(lhs.len, rhs.len);
 }
 
-/// Compares two many-item pointers with NUL-termination lexicographically.
-pub fn orderZ(comptime T: type, lhs: [*:0]const T, rhs: [*:0]const T) math.Order {
+/// Compares two many-item pointers with sentinel-termination lexicographically.
+pub fn orderSentinel(comptime T: type, comptime s: T, lhs: [*:s]const T, rhs: [*:s]const T) math.Order {
     var i: usize = 0;
-    while (lhs[i] == rhs[i] and lhs[i] != 0) : (i += 1) {}
-    return math.order(lhs[i], rhs[i]);
+    while (lhs[i] == rhs[i] and lhs[i] != s) : (i += 1) {}
+    if (lhs[i] == s) {
+        return if (rhs[i] == s) .eq else .lt;
+    } else if (rhs[i] == s) {
+        return .gt;
+    } else {
+        return math.order(lhs[i], rhs[i]);
+    }
+}
+/// Deprecated in favor of `orderSentinel`.
+pub fn orderZ(comptime T: type, lhs: [*:0]const T, rhs: [*:0]const T) math.Order {
+    return orderSentinel(T, 0, lhs, rhs);
 }
 
 test order {
@@ -671,8 +681,20 @@ test order {
     try testing.expect(order(u8, "abc", "abc0") == .lt);
     try testing.expect(order(u8, "", "") == .eq);
     try testing.expect(order(u8, "", "a") == .lt);
+    try testing.expect(order(i8, &.{ -1, -2 }, &.{ -1, -2, -3 }) == .lt);
 }
 
+test orderSentinel {
+    try testing.expect(orderSentinel(u8, 0, "abcd", "bee") == .lt);
+    try testing.expect(orderSentinel(u8, 0, "abc", "abc") == .eq);
+    try testing.expect(orderSentinel(u8, 0, "abc", "abc0") == .lt);
+    try testing.expect(orderSentinel(u8, 0, "", "") == .eq);
+    try testing.expect(orderSentinel(u8, 0, "", "a") == .lt);
+    try testing.expect(orderSentinel(i8, 0, &.{ -1, -2 }, &.{ -1, -2, -3 }) == .lt);
+    try testing.expect(orderSentinel(u4, 4, &.{ 1, 2, 3 }, &.{ 1, 2, 3 }) == .eq);
+    try testing.expect(orderSentinel(u4, 4, &.{ 1, 2, 3 }, &.{ 1, 2 }) == .gt);
+    try testing.expect(orderSentinel(u4, 4, &.{ 1, 2, 3 }, &.{ 1, 2, 3, 5 }) == .lt);
+}
 test orderZ {
     try testing.expect(orderZ(u8, "abcd", "bee") == .lt);
     try testing.expect(orderZ(u8, "abc", "abc") == .eq);
diff --git a/lib/std/zig/c_builtins.zig b/lib/std/zig/c_builtins.zig
index 2f6c2e8aa5d7..71a80299dd8d 100644
--- a/lib/std/zig/c_builtins.zig
+++ b/lib/std/zig/c_builtins.zig
@@ -132,7 +132,7 @@ pub inline fn __builtin_strlen(s: [*c]const u8) usize {
     return std.mem.sliceTo(s, 0).len;
 }
 pub inline fn __builtin_strcmp(s1: [*c]const u8, s2: [*c]const u8) c_int {
-    return switch (std.mem.orderZ(u8, s1, s2)) {
+    return switch (std.mem.orderSentinel(u8, 0, s1, s2)) {
         .lt => -1,
         .eq => 0,
         .gt => 1,

From 6d2e76b48b8285c079f73a27da272e036d0af04f Mon Sep 17 00:00:00 2001
From: IOKG04 <iokg04@gmail.com>
Date: Fri, 19 Sep 2025 14:48:58 +0200
Subject: [PATCH 2/2] `dupeSentinel` instead of `dupeZ`

closes https://github.com/ziglang/zig/issues/25285
---
 lib/compiler/aro/aro/CodeGen.zig |  4 ++--
 lib/std/Build/Watch/FsEvents.zig |  2 +-
 lib/std/debug.zig                |  2 +-
 lib/std/fs/get_app_data_dir.zig  |  2 +-
 lib/std/fs/test.zig              |  4 ++--
 lib/std/mem.zig                  |  2 +-
 lib/std/mem/Allocator.zig        | 12 ++++++++----
 lib/std/net.zig                  |  4 ++--
 lib/std/os/plan9.zig             |  2 +-
 lib/std/process.zig              |  4 ++--
 lib/std/process/Child.zig        |  2 +-
 lib/std/zig/LibCInstallation.zig | 20 ++++++++++----------
 lib/std/zig/tokenizer.zig        |  2 +-
 src/Compilation.zig              |  4 ++--
 src/codegen/llvm.zig             |  2 +-
 src/libs/mingw.zig               |  2 +-
 src/link/Lld.zig                 |  4 ++--
 src/main.zig                     | 10 +++++-----
 18 files changed, 44 insertions(+), 40 deletions(-)

diff --git a/lib/compiler/aro/aro/CodeGen.zig b/lib/compiler/aro/aro/CodeGen.zig
index bfffb4117eea..505002921499 100644
--- a/lib/compiler/aro/aro/CodeGen.zig
+++ b/lib/compiler/aro/aro/CodeGen.zig
@@ -978,7 +978,7 @@ fn genLval(c: *CodeGen, node: NodeIndex) Error!Ir.Ref {
                 }
             }
 
-            const duped_name = try c.builder.arena.allocator().dupeZ(u8, slice);
+            const duped_name = try c.builder.arena.allocator().dupeSentinel(u8, slice, 0);
             const ref: Ir.Ref = @enumFromInt(c.builder.instructions.len);
             try c.builder.instructions.append(c.builder.gpa, .{ .tag = .symbol, .data = .{ .label = duped_name }, .ty = .ptr });
             return ref;
@@ -1200,7 +1200,7 @@ fn genCall(c: *CodeGen, fn_node: NodeIndex, arg_nodes: []const NodeIndex, ty: Ty
                     }
                 }
 
-                const duped_name = try c.builder.arena.allocator().dupeZ(u8, slice);
+                const duped_name = try c.builder.arena.allocator().dupeSentinel(u8, slice, 0);
                 const ref: Ir.Ref = @enumFromInt(c.builder.instructions.len);
                 try c.builder.instructions.append(c.builder.gpa, .{ .tag = .symbol, .data = .{ .label = duped_name }, .ty = .ptr });
                 break :blk ref;
diff --git a/lib/std/Build/Watch/FsEvents.zig b/lib/std/Build/Watch/FsEvents.zig
index c8c53813c2fb..d9c3e29f5fc0 100644
--- a/lib/std/Build/Watch/FsEvents.zig
+++ b/lib/std/Build/Watch/FsEvents.zig
@@ -193,7 +193,7 @@ pub fn setPaths(fse: *FsEvents, gpa: Allocator, steps: []const *std.Build.Step)
     } else {
         fse.watch_roots = try gpa.realloc(fse.watch_roots, need_dirs.count());
         for (fse.watch_roots, need_dirs.keys()) |*out, in| {
-            out.* = try paths_arena.dupeZ(u8, in);
+            out.* = try paths_arena.dupeSentinel(u8, in, 0);
         }
     }
     if (enable_debug_logs) {
diff --git a/lib/std/debug.zig b/lib/std/debug.zig
index bd849a32d320..d2ecf95b21b5 100644
--- a/lib/std/debug.zig
+++ b/lib/std/debug.zig
@@ -661,7 +661,7 @@ pub fn defaultPanic(
 
             if (uefi.system_table.boot_services) |bs| {
                 // ExitData buffer must be allocated using boot_services.allocatePool (spec: page 220)
-                const exit_data = uefi.raw_pool_allocator.dupeZ(u16, exit_msg) catch @trap();
+                const exit_data = uefi.raw_pool_allocator.dupeSentinel(u16, exit_msg, 0) catch @trap();
                 bs.exit(uefi.handle, .aborted, exit_data) catch {};
             }
             @trap();
diff --git a/lib/std/fs/get_app_data_dir.zig b/lib/std/fs/get_app_data_dir.zig
index a256758a07e2..5b0c0d79271c 100644
--- a/lib/std/fs/get_app_data_dir.zig
+++ b/lib/std/fs/get_app_data_dir.zig
@@ -46,7 +46,7 @@ pub fn getAppDataDir(allocator: mem.Allocator, appname: []const u8) GetAppDataDi
         .haiku => {
             var dir_path_buf: [std.fs.max_path_bytes]u8 = undefined;
             const rc = std.c.find_directory(.B_USER_SETTINGS_DIRECTORY, -1, true, &dir_path_buf, dir_path_buf.len);
-            const settings_dir = try allocator.dupeZ(u8, mem.sliceTo(&dir_path_buf, 0));
+            const settings_dir = try allocator.dupeSentinel(u8, mem.sliceTo(&dir_path_buf, 0), 0);
             defer allocator.free(settings_dir);
             switch (rc) {
                 0 => return fs.path.join(allocator, &[_][]const u8{ settings_dir, appname }),
diff --git a/lib/std/fs/test.zig b/lib/std/fs/test.zig
index 65e86e4c2e40..c97a4781f600 100644
--- a/lib/std/fs/test.zig
+++ b/lib/std/fs/test.zig
@@ -105,7 +105,7 @@ const TestContext = struct {
         const allocator = self.arena.allocator();
         const transformed_path = try self.transform_fn(allocator, self.dir, relative_path);
         if (native_os == .windows) {
-            const transformed_sep_path = try allocator.dupeZ(u8, transformed_path);
+            const transformed_sep_path = try allocator.dupeSentinel(u8, transformed_path, 0);
             std.mem.replaceScalar(u8, transformed_sep_path, switch (self.path_sep) {
                 '/' => '\\',
                 '\\' => '/',
@@ -123,7 +123,7 @@ const TestContext = struct {
     pub fn toCanonicalPathSep(self: *TestContext, path: [:0]const u8) ![:0]const u8 {
         if (native_os == .windows) {
             const allocator = self.arena.allocator();
-            const transformed_sep_path = try allocator.dupeZ(u8, path);
+            const transformed_sep_path = try allocator.dupeSentinel(u8, path, 0);
             std.mem.replaceScalar(u8, transformed_sep_path, '/', '\\');
             return transformed_sep_path;
         }
diff --git a/lib/std/mem.zig b/lib/std/mem.zig
index 0036c3bda257..ac46b5774fb1 100644
--- a/lib/std/mem.zig
+++ b/lib/std/mem.zig
@@ -4711,7 +4711,7 @@ test isAligned {
 }
 
 test "freeing empty string with null-terminated sentinel" {
-    const empty_string = try testing.allocator.dupeZ(u8, "");
+    const empty_string = try testing.allocator.dupeSentinel(u8, "", 0);
     testing.allocator.free(empty_string);
 }
 
diff --git a/lib/std/mem/Allocator.zig b/lib/std/mem/Allocator.zig
index 1d1653d3a0c9..461a90490e7d 100644
--- a/lib/std/mem/Allocator.zig
+++ b/lib/std/mem/Allocator.zig
@@ -451,12 +451,16 @@ pub fn dupe(allocator: Allocator, comptime T: type, m: []const T) Error![]T {
     return new_buf;
 }
 
-/// Copies `m` to newly allocated memory, with a null-terminated element. Caller owns the memory.
-pub fn dupeZ(allocator: Allocator, comptime T: type, m: []const T) Error![:0]T {
+/// Copies `m` to newly allocated memory, with a sentinel-terminated element. Caller owns the memory.
+pub fn dupeSentinel(allocator: Allocator, comptime T: type, m: []const T, comptime s: T) Error![:s]T {
     const new_buf = try allocator.alloc(T, m.len + 1);
     @memcpy(new_buf[0..m.len], m);
-    new_buf[m.len] = 0;
-    return new_buf[0..m.len :0];
+    new_buf[m.len] = s;
+    return new_buf[0..m.len :s];
+}
+/// Deprecated in favor of `dupeSentinel`
+pub fn dupeZ(allocator: Allocator, comptime T: type, m: []const T) Error![:0]T {
+    return try dupeSentinel(allocator, T, m, 0);
 }
 
 /// An allocator that always fails to allocate.
diff --git a/lib/std/net.zig b/lib/std/net.zig
index 37fe2734d52d..794c81516869 100644
--- a/lib/std/net.zig
+++ b/lib/std/net.zig
@@ -910,7 +910,7 @@ pub fn getAddressList(gpa: Allocator, name: []const u8, port: u16) GetAddressLis
     errdefer result.deinit();
 
     if (native_os == .windows) {
-        const name_c = try gpa.dupeZ(u8, name);
+        const name_c = try gpa.dupeSentinel(u8, name, 0);
         defer gpa.free(name_c);
 
         const port_c = try std.fmt.allocPrintSentinel(gpa, "{d}", .{port}, 0);
@@ -982,7 +982,7 @@ pub fn getAddressList(gpa: Allocator, name: []const u8, port: u16) GetAddressLis
     }
 
     if (builtin.link_libc) {
-        const name_c = try gpa.dupeZ(u8, name);
+        const name_c = try gpa.dupeSentinel(u8, name, 0);
         defer gpa.free(name_c);
 
         const port_c = try std.fmt.allocPrintSentinel(gpa, "{d}", .{port}, 0);
diff --git a/lib/std/os/plan9.zig b/lib/std/os/plan9.zig
index b910e26c7134..4464095db3d0 100644
--- a/lib/std/os/plan9.zig
+++ b/lib/std/os/plan9.zig
@@ -297,7 +297,7 @@ pub fn openat(dirfd: i32, path: [*:0]const u8, flags: u32, _: mode_t) usize {
     const dir_path = std.mem.span(@as([*:0]u8, @ptrCast(&dir_path_buf)));
     const total_path = std.fs.path.join(alloc, &.{ dir_path, std.mem.span(path) }) catch unreachable; // the allocation shouldn't fail because it should not exceed max_path_bytes
     fba.reset();
-    const total_path_z = alloc.dupeZ(u8, total_path) catch unreachable; // should not exceed max_path_bytes + 1
+    const total_path_z = alloc.dupeSentinel(u8, total_path, 0) catch unreachable; // should not exceed max_path_bytes + 1
     return open(total_path_z.ptr, flags);
 }
 
diff --git a/lib/std/process.zig b/lib/std/process.zig
index 10025a5ea5b8..4260a4140c00 100644
--- a/lib/std/process.zig
+++ b/lib/std/process.zig
@@ -1721,7 +1721,7 @@ pub fn execve(
     const arena = arena_allocator.allocator();
 
     const argv_buf = try arena.allocSentinel(?[*:0]const u8, argv.len, null);
-    for (argv, 0..) |arg, i| argv_buf[i] = (try arena.dupeZ(u8, arg)).ptr;
+    for (argv, 0..) |arg, i| argv_buf[i] = (try arena.dupeSentinel(u8, arg, 0)).ptr;
 
     const envp = m: {
         if (env_map) |m| {
@@ -1999,7 +1999,7 @@ pub fn createEnvironFromExisting(
             },
             .nothing => {},
         };
-        envp_buf[i] = try arena.dupeZ(u8, mem.span(line));
+        envp_buf[i] = try arena.dupeSentinel(u8, mem.span(line), 0);
         i += 1;
     }
 
diff --git a/lib/std/process/Child.zig b/lib/std/process/Child.zig
index bbc08ac0c9f7..6b69e84a714c 100644
--- a/lib/std/process/Child.zig
+++ b/lib/std/process/Child.zig
@@ -591,7 +591,7 @@ fn spawnPosix(self: *ChildProcess) SpawnError!void {
     // Therefore, we do all the allocation for the execve() before the fork().
     // This means we must do the null-termination of argv and env vars here.
     const argv_buf = try arena.allocSentinel(?[*:0]const u8, self.argv.len, null);
-    for (self.argv, 0..) |arg, i| argv_buf[i] = (try arena.dupeZ(u8, arg)).ptr;
+    for (self.argv, 0..) |arg, i| argv_buf[i] = (try arena.dupeSentinel(u8, arg, 0)).ptr;
 
     const prog_fileno = 3;
     comptime assert(@max(posix.STDIN_FILENO, posix.STDOUT_FILENO, posix.STDERR_FILENO) + 1 == prog_fileno);
diff --git a/lib/std/zig/LibCInstallation.zig b/lib/std/zig/LibCInstallation.zig
index 0414d32ee7d6..782947ff4e1b 100644
--- a/lib/std/zig/LibCInstallation.zig
+++ b/lib/std/zig/LibCInstallation.zig
@@ -58,7 +58,7 @@ pub fn parse(
                 if (value.len == 0) {
                     @field(self, field.name) = null;
                 } else {
-                    found_keys[i].allocated = try allocator.dupeZ(u8, value);
+                    found_keys[i].allocated = try allocator.dupeSentinel(u8, value, 0);
                     @field(self, field.name) = found_keys[i].allocated;
                 }
                 break;
@@ -197,16 +197,16 @@ pub fn findNative(args: FindNativeOptions) FindError!LibCInstallation {
     } else if (is_haiku) {
         try self.findNativeIncludeDirPosix(args);
         try self.findNativeGccDirHaiku(args);
-        self.crt_dir = try args.allocator.dupeZ(u8, "/system/develop/lib");
+        self.crt_dir = try args.allocator.dupeSentinel(u8, "/system/develop/lib", 0);
     } else if (builtin.target.os.tag.isSolarish()) {
         // There is only one libc, and its headers/libraries are always in the same spot.
-        self.include_dir = try args.allocator.dupeZ(u8, "/usr/include");
-        self.sys_include_dir = try args.allocator.dupeZ(u8, "/usr/include");
-        self.crt_dir = try args.allocator.dupeZ(u8, "/usr/lib/64");
+        self.include_dir = try args.allocator.dupeSentinel(u8, "/usr/include", 0);
+        self.sys_include_dir = try args.allocator.dupeSentinel(u8, "/usr/include", 0);
+        self.crt_dir = try args.allocator.dupeSentinel(u8, "/usr/lib/64", 0);
     } else if (std.process.can_spawn) {
         try self.findNativeIncludeDirPosix(args);
         switch (builtin.target.os.tag) {
-            .freebsd, .netbsd, .openbsd, .dragonfly => self.crt_dir = try args.allocator.dupeZ(u8, "/usr/lib"),
+            .freebsd, .netbsd, .openbsd, .dragonfly => self.crt_dir = try args.allocator.dupeSentinel(u8, "/usr/lib", 0),
             .linux => try self.findNativeCrtDirPosix(args),
             else => {},
         }
@@ -330,7 +330,7 @@ fn findNativeIncludeDirPosix(self: *LibCInstallation, args: FindNativeOptions) F
 
         if (self.include_dir == null) {
             if (search_dir.accessZ(include_dir_example_file, .{})) |_| {
-                self.include_dir = try allocator.dupeZ(u8, search_path);
+                self.include_dir = try allocator.dupeSentinel(u8, search_path, 0);
             } else |err| switch (err) {
                 error.FileNotFound => {},
                 else => return error.FileSystem,
@@ -339,7 +339,7 @@ fn findNativeIncludeDirPosix(self: *LibCInstallation, args: FindNativeOptions) F
 
         if (self.sys_include_dir == null) {
             if (search_dir.accessZ(sys_include_dir_example_file, .{})) |_| {
-                self.sys_include_dir = try allocator.dupeZ(u8, search_path);
+                self.sys_include_dir = try allocator.dupeSentinel(u8, search_path, 0);
             } else |err| switch (err) {
                 error.FileNotFound => {},
                 else => return error.FileSystem,
@@ -622,10 +622,10 @@ fn ccPrintFileName(args: CCPrintFileNameOptions) ![:0]u8 {
     // So we detect failure by checking if the output matches exactly the input.
     if (std.mem.eql(u8, line, args.search_basename)) return error.LibCRuntimeNotFound;
     switch (args.want_dirname) {
-        .full_path => return allocator.dupeZ(u8, line),
+        .full_path => return allocator.dupeSentinel(u8, line, 0),
         .only_dir => {
             const dirname = fs.path.dirname(line) orelse return error.LibCRuntimeNotFound;
-            return allocator.dupeZ(u8, dirname);
+            return allocator.dupeSentinel(u8, dirname, 0);
         },
     }
 }
diff --git a/lib/std/zig/tokenizer.zig b/lib/std/zig/tokenizer.zig
index de04ba41fecd..605c326c172c 100644
--- a/lib/std/zig/tokenizer.zig
+++ b/lib/std/zig/tokenizer.zig
@@ -1723,7 +1723,7 @@ fn testTokenize(source: [:0]const u8, expected_token_tags: []const Token.Tag) !v
 
 fn testPropertiesUpheld(context: void, source: []const u8) anyerror!void {
     _ = context;
-    const source0 = try std.testing.allocator.dupeZ(u8, source);
+    const source0 = try std.testing.allocator.dupeSentinel(u8, source, 0);
     defer std.testing.allocator.free(source0);
     var tokenizer = Tokenizer.init(source0);
     var tokenization_failed = false;
diff --git a/src/Compilation.zig b/src/Compilation.zig
index 34953ed11a12..fead05b1918a 100644
--- a/src/Compilation.zig
+++ b/src/Compilation.zig
@@ -1933,7 +1933,7 @@ pub fn create(gpa: Allocator, arena: Allocator, diag: *CreateDiagnostic, options
     const comp: *Compilation = comp: {
         // We put the `Compilation` itself in the arena. Freeing the arena will free the module.
         // It's initialized later after we prepare the initialization options.
-        const root_name = try arena.dupeZ(u8, options.root_name);
+        const root_name = try arena.dupeSentinel(u8, options.root_name, 0);
 
         // The "any" values provided by resolved config only account for
         // explicitly-provided settings. We now make them additionally account
@@ -5706,7 +5706,7 @@ pub fn cImport(comp: *Compilation, c_src: []const u8, owner_mod: *Package.Module
                 new_argv_with_sentinel[argv.items.len] = null;
                 const new_argv = new_argv_with_sentinel[0..argv.items.len :null];
                 for (argv.items, 0..) |arg, i| {
-                    new_argv[i] = try arena.dupeZ(u8, arg);
+                    new_argv[i] = try arena.dupeSentinel(u8, arg, 0);
                 }
 
                 const c_headers_dir_path_z = try comp.dirs.zig_lib.joinZ(arena, &.{"include"});
diff --git a/src/codegen/llvm.zig b/src/codegen/llvm.zig
index ebdcdb6bcbf9..2781ac14ce52 100644
--- a/src/codegen/llvm.zig
+++ b/src/codegen/llvm.zig
@@ -936,7 +936,7 @@ pub const Object = struct {
         }
 
         const target_triple_sentinel =
-            try o.gpa.dupeZ(u8, o.builder.target_triple.slice(&o.builder).?);
+            try o.gpa.dupeSentinel(u8, o.builder.target_triple.slice(&o.builder).?, 0);
         defer o.gpa.free(target_triple_sentinel);
 
         const emit_asm_msg = options.asm_path orelse "(none)";
diff --git a/src/libs/mingw.zig b/src/libs/mingw.zig
index 5106815eff93..687428722131 100644
--- a/src/libs/mingw.zig
+++ b/src/libs/mingw.zig
@@ -345,7 +345,7 @@ pub fn buildImportLib(comp: *Compilation, lib_name: []const u8) !void {
 
     if (!build_options.have_llvm) return error.ZigCompilerNotBuiltWithLLVMExtensions;
     const llvm_bindings = @import("../codegen/llvm/bindings.zig");
-    const def_final_path_z = try arena.dupeZ(u8, def_final_path);
+    const def_final_path_z = try arena.dupeSentinel(u8, def_final_path, 0);
     const lib_final_path_z = try comp.dirs.global_cache.joinZ(arena, &.{lib_final_path});
     if (llvm_bindings.WriteImportLibrary(
         def_final_path_z.ptr,
diff --git a/src/link/Lld.zig b/src/link/Lld.zig
index c1845b9a727f..a28487152e08 100644
--- a/src/link/Lld.zig
+++ b/src/link/Lld.zig
@@ -286,7 +286,7 @@ fn linkAsArchive(lld: *Lld, arena: Allocator) !void {
     const comp = base.comp;
     const directory = base.emit.root_dir; // Just an alias to make it shorter to type.
     const full_out_path = try directory.join(arena, &[_][]const u8{base.emit.sub_path});
-    const full_out_path_z = try arena.dupeZ(u8, full_out_path);
+    const full_out_path_z = try arena.dupeSentinel(u8, full_out_path, 0);
     const opt_zcu = comp.zcu;
 
     const zcu_obj_path: ?Cache.Path = if (opt_zcu != null) p: {
@@ -325,7 +325,7 @@ fn linkAsArchive(lld: *Lld, arena: Allocator) !void {
         object_files.appendAssumeCapacity(try key.status.success.object_path.toStringZ(arena));
     }
     for (comp.win32_resource_table.keys()) |key| {
-        object_files.appendAssumeCapacity(try arena.dupeZ(u8, key.status.success.res_path));
+        object_files.appendAssumeCapacity(try arena.dupeSentinel(u8, key.status.success.res_path, 0));
     }
     if (zcu_obj_path) |p| object_files.appendAssumeCapacity(try p.toStringZ(arena));
     if (compiler_rt_path) |p| object_files.appendAssumeCapacity(try p.toStringZ(arena));
diff --git a/src/main.zig b/src/main.zig
index eef7b75fd0e7..b2153a8dc706 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -4495,7 +4495,7 @@ fn runOrTestHotSwap(
             const arena = arena_allocator.allocator();
 
             const argv_buf = try arena.allocSentinel(?[*:0]u8, argv.items.len, null);
-            for (argv.items, 0..) |arg, i| argv_buf[i] = (try arena.dupeZ(u8, arg)).ptr;
+            for (argv.items, 0..) |arg, i| argv_buf[i] = (try arena.dupeSentinel(u8, arg, 0)).ptr;
 
             const pid = try PosixSpawn.spawn(argv.items[0], null, attr, argv_buf, std.c.environ);
             return pid;
@@ -4623,10 +4623,10 @@ fn cmdTranslateC(
                 new_argv_with_sentinel[clang_args_len] = null;
                 const new_argv = new_argv_with_sentinel[0..clang_args_len :null];
                 for (argv.items, 0..) |arg, i| {
-                    new_argv[i] = try arena.dupeZ(u8, arg);
+                    new_argv[i] = try arena.dupeSentinel(u8, arg, 0);
                 }
                 for (c_source_file.extra_flags, 0..) |arg, i| {
-                    new_argv[argv.items.len + i] = try arena.dupeZ(u8, arg);
+                    new_argv[argv.items.len + i] = try arena.dupeSentinel(u8, arg, 0);
                 }
 
                 const c_headers_dir_path_z = try comp.dirs.zig_lib.joinZ(arena, &.{"include"});
@@ -5741,7 +5741,7 @@ extern "c" fn ZigLlvmAr_main(argc: c_int, argv: [*:null]?[*:0]u8) c_int;
 fn argsCopyZ(alloc: Allocator, args: []const []const u8) ![:null]?[*:0]u8 {
     var argv = try alloc.allocSentinel(?[*:0]u8, args.len, null);
     for (args, 0..) |arg, i| {
-        argv[i] = try alloc.dupeZ(u8, arg); // TODO If there was an argsAllocZ we could avoid this allocation.
+        argv[i] = try alloc.dupeSentinel(u8, arg, 0); // TODO If there was an argsAllocZ we could avoid this allocation.
     }
     return argv;
 }
@@ -6463,7 +6463,7 @@ fn cmdDumpLlvmInts(
     if (!build_options.have_llvm)
         fatal("compiler does not use LLVM; cannot dump LLVM integer sizes", .{});
 
-    const triple = try arena.dupeZ(u8, args[0]);
+    const triple = try arena.dupeSentinel(u8, args[0], 0);
 
     const llvm = @import("codegen/llvm/bindings.zig");