Commit `bd46410419`

Andrew Kelley <andrew@ziglang.org>

2024-01-14 07:20:33

Revert "Merge pull request #18410 from dweiller/by-length-slice-bug"

This reverts commit d9d840a33ac8abb0e616de862f592821a7f4a35e, reversing changes made to a04d4330945565b8d6f298ace993f6954c42d0f3. This is not an adequate implementation of the missing safety check, as evidenced by the changes to std.json that are reverted in this commit. Reopens #18382 Closes #18510

master

1 parent 0f9345e

Changed files (4)

lib

std

json

static.zig

src

Sema.zig

test

cases

compile_errors

slice_of_array_by-length_oversized.zig

safety

array slice by-length oversized.zig

@@ -402,33 +402,21 @@ pub fn innerParse(
                             },
                             .partial_string_escaped_1 => |arr| {
                                 if (i + arr.len > r.len) return error.LengthMismatch;
-                                // tell the compiler that the by-length slice below is valid;
-                                // this assert is required for the inequality to be comptime-known
-                                if (arr.len > r.len) unreachable;
                                 @memcpy(r[i..][0..arr.len], arr[0..]);
                                 i += arr.len;
                             },
                             .partial_string_escaped_2 => |arr| {
                                 if (i + arr.len > r.len) return error.LengthMismatch;
-                                // tell the compiler that the by-length slice below is valid;
-                                // this assert is required for the inequality to be comptime-known
-                                if (arr.len > r.len) unreachable;
                                 @memcpy(r[i..][0..arr.len], arr[0..]);
                                 i += arr.len;
                             },
                             .partial_string_escaped_3 => |arr| {
                                 if (i + arr.len > r.len) return error.LengthMismatch;
-                                // tell the compiler that the by-length slice below is valid;
-                                // this assert is required for the inequality to be comptime-known
-                                if (arr.len > r.len) unreachable;
                                 @memcpy(r[i..][0..arr.len], arr[0..]);
                                 i += arr.len;
                             },
                             .partial_string_escaped_4 => |arr| {
                                 if (i + arr.len > r.len) return error.LengthMismatch;
-                                // tell the compiler that the by-length slice below is valid;
-                                // this assert is required for the inequality to be comptime-known
-                                if (arr.len > r.len) unreachable;
                                 @memcpy(r[i..][0..arr.len], arr[0..]);
                                 i += arr.len;
                             },

@@ -32635,30 +32635,6 @@ fn analyzeSlice(
             if (!end_is_len) {
                 const end = if (by_length) end: {
                     const len = try sema.coerce(block, Type.usize, uncasted_end_opt, end_src);
-                    if (try sema.resolveValue(len)) |slice_len_val| {
-                        const len_s_val = try mod.intValue(
-                            Type.usize,
-                            array_ty.arrayLenIncludingSentinel(mod),
-                        );
-                        if (!(try sema.compareScalar(slice_len_val, .lte, len_s_val, Type.usize))) {
-                            const sentinel_label: []const u8 = if (array_ty.sentinel(mod) != null)
-                                " +1 (sentinel)"
-                            else
-                                "";
-
-                            return sema.fail(
-                                block,
-                                end_src,
-                                "length {} out of bounds for array of length {}{s}",
-                                .{
-                                    slice_len_val.fmtValue(Type.usize, mod),
-                                    len_val.fmtValue(Type.usize, mod),
-                                    sentinel_label,
-                                },
-                            );
-                        }
-                    }
-                    // check len is less than array size if comptime known
                     const uncasted_end = try sema.analyzeArithmetic(block, .add, start, len, src, start_src, end_src, false);
                     break :end try sema.coerce(block, Type.usize, uncasted_end, end_src);
                 } else try sema.coerce(block, Type.usize, uncasted_end_opt, end_src);

@@ -1,19 +0,0 @@
-export fn entry1() void {
-    var buf: [5]u8 = undefined;
-    var a: u32 = 6;
-    _ = &a;
-    _ = buf[a..][0..10];
-}
-
-export fn entry2() void {
-    var buf: [5]u8 = undefined;
-    const a: u32 = 6;
-    _ = buf[a..][0..10];
-}
-
-// error
-// backend=stage2
-// target=native
-//
-// :5:21: error: length 10 out of bounds for array of length 5
-// :11:21: error: length 10 out of bounds for array of length 5

@@ -1,21 +0,0 @@
-const std = @import("std");
-
-pub fn panic(message: []const u8, stack_trace: ?*std.builtin.StackTrace, _: ?usize) noreturn {
-    _ = stack_trace;
-    if (std.mem.eql(u8, message, "index out of bounds: index 12, len 5")) {
-        std.process.exit(0);
-    }
-    std.process.exit(1);
-}
-
-pub fn main() !void {
-    var buf: [5]u8 = undefined;
-    var a: u32 = 6;
-    _ = &a;
-    _ = buf[a..][0..a];
-    return error.TestFailed;
-}
-
-// run
-// backend=llvm
-// target=native

Commit bd46410419

Commit `bd46410419`