zig

commit 5c133c5765f3c4e80d46c35c104edc23d883c60e (tree)
parent f414370fba47e375cc240f3fcaa8fa36c7c0fed3
Author: Andrew Kelley <andrew@ziglang.org>
Date:   Tue, 19 May 2026 16:29:49 -0700

Configuration: fix deserialization of LengthPrefixedList

don't assume only 1 field

Diffstat:
M
BRANCH_TODO
 | 
3
++-
M
lib/std/Build/Configuration.zig
 | 
20
++++++++++++--------

2 files changed, 14 insertions(+), 9 deletions(-)
diff --git a/BRANCH_TODO b/BRANCH_TODO
@@ -1,4 +1,4 @@
-* WriteFile step failing when making langref
+* Run step getting wrong path_directory values
 * double check when targets get resolved (should be at configure time)
 * finish migrating the rest of the build steps
 * pass overridden pkg-dir to maker
@@ -39,6 +39,7 @@
 * WriteFiles: introduce Group
 * re-examine the use case of adding file paths to Options steps
 * extract the reusable Configure abstractions and reuse it for Zir etc
+* add the ability to delete files to UpdateSourceFiles
 
 ## Already Filed Followup Issues
 * build system fmt step with check=false does not acquire a write lock on source files #35204 
diff --git a/lib/std/Build/Configuration.zig b/lib/std/Build/Configuration.zig
@@ -2545,8 +2545,10 @@ pub const Storage = enum {
         };
     }
 
-    /// The field contains a u32 length followed by that many items, each
-    /// element bitcastable to u32.
+    /// The field contains a u32 length followed by that many items. Each
+    /// element needs well-defined memory layout but can otherwise be any
+    /// multiple of u32 length. The length is number of elements, not the
+    /// number of u32s.
     pub fn LengthPrefixedList(comptime ElemArg: type) type {
         return struct {
             slice: []const Elem,
@@ -2759,19 +2761,21 @@ pub const Storage = enum {
                         },
                         .extended => @compileError("TODO"),
                         .length_prefixed_list => {
+                            const n = @divExact(@sizeOf(Field.Elem), @sizeOf(u32));
                             const data_start = i.* + 1;
-                            const len = buffer[data_start - 1];
-                            defer i.* = data_start + len;
-                            return .{ .slice = @ptrCast(buffer[data_start..][0..len]) };
+                            const buf_len = buffer[data_start - 1] * n;
+                            defer i.* = data_start + buf_len;
+                            return .{ .slice = @ptrCast(buffer[data_start..][0..buf_len]) };
                         },
                         .flag_length_prefixed_list => {
                             const flags = @field(container, @tagName(Field.flags));
                             const flag = @field(flags, @tagName(Field.flag));
                             if (!flag) return .{ .slice = &.{} };
+                            const n = @divExact(@sizeOf(Field.Elem), @sizeOf(u32));
                             const data_start = i.* + 1;
-                            const len = buffer[data_start - 1];
-                            defer i.* = data_start + len;
-                            return .{ .slice = @ptrCast(buffer[data_start..][0..len]) };
+                            const buf_len = buffer[data_start - 1] * n;
+                            defer i.* = data_start + buf_len;
+                            return .{ .slice = @ptrCast(buffer[data_start..][0..buf_len]) };
                         },
                         .flag_list => {
                             const flags = @field(container, @tagName(Field.flags));