Improper format triggered from build.zig

[Validark]

Zig Version

0.12.0-dev.3630+215de3ee6

Steps to Reproduce and Observed Behavior

Running these commands:

mkdir bad-zig-project
cd ./bad-zig-project
zig init
zig fetch --save https://github.com/InKryption/rpmalloc-zig-port/archive/56966ca426ef13efa0ab5223fc27aade4866b6a4.tar.gz
sed -i '$s/}$/\n    const rpmalloc = b.dependency("rpmalloc-zig-port", .{ .target = target, .optimize = optimize });\n    exe.root_module.addImport("rpmalloc", rpmalloc.module("rpmalloc"));\n}/' ./build.zig
zig build -freference-trace

produces this error:

/home/niles/zig/0.12.0-dev.3630+215de3ee6/files/lib/std/zig.zig:804:13: error: expected {}, {p}, {_}, {p_} or {_p}, found {s}
            @compileError("expected {}, {p}, {_}, {p_} or {_p}, found {" ++ fmt ++ "}");

Expected Behavior

Expected no error.

The following change makes it "work", but I doubt this is the appropriate fix.

/// Print the string as a Zig identifier, escaping it with `@""` syntax if needed.
fn formatId(
    bytes: []const u8,
    comptime fmt: []const u8,
    options: std.fmt.FormatOptions,
    writer: anytype,
) !void {
    const allow_primitive, const allow_underscore = comptime parse_fmt: {
        var allow_primitive = false;
        var allow_underscore = false;
        for (fmt) |char| {
            switch (char) {
                'p' => if (!allow_primitive) {
                    allow_primitive = true;
                    continue;
                },
                '_' => if (!allow_underscore) {
                    allow_underscore = true;
                    continue;
                },
+               's' => continue,
                else => {},
            }
            @compileError("expected {}, {p}, {_}, {p_} or {_p}, found {" ++ fmt ++ "}");
        }
        break :parse_fmt .{ allow_primitive, allow_underscore };
    };

    if (isValidId(bytes) and
        (allow_primitive or !std.zig.isPrimitive(bytes)) and
        (allow_underscore or !isUnderscore(bytes)))
    {
        return writer.writeAll(bytes);
    }
    try writer.writeAll("@\"");
    try stringEscape(bytes, "", options, writer);
    try writer.writeByte('"');
}

[ianprime0509]

The issue appears to be here: https://github.com/InKryption/rpmalloc-zig-port/blob/56966ca426ef13efa0ab5223fc27aade4866b6a4/build.zig#L73 This should be {}, not {s}; as the error message indicates, std.zig.fmtId does not allow the format specifier {s} as of #18920.

However, the reference trace seems to be misleading in this case, which might be a bug:

/var/home/ian/src/zig/lib/std/zig.zig:804:13: error: expected {}, {p}, {_}, {p_} or {_p}, found {s}
            @compileError("expected {}, {p}, {_}, {p_} or {_p}, found {" ++ fmt ++ "}");
            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
referenced by:
    format__anon_20497: /var/home/ian/src/zig/lib/std/fmt.zig:1480:26
    formatType__anon_20340: /var/home/ian/src/zig/lib/std/fmt.zig:494:32
    format__anon_19633: /var/home/ian/src/zig/lib/std/fmt.zig:185:23
    print__anon_18932: /var/home/ian/src/zig/lib/std/io/Writer.zig:23:26
    print: /var/home/ian/src/zig/lib/std/io.zig:324:47
    printType__anon_20563: /var/home/ian/src/zig/lib/std/Build/Step/Options.zig:73:24
    addOptionFallible__anon_20562: /var/home/ian/src/zig/lib/std/Build/Step/Options.zig:44:18
    addOption__anon_20480: /var/home/ian/src/zig/lib/std/Build/Step/Options.zig:39:29
    make: /var/home/ian/src/zig/lib/std/Build/Step/Options.zig:421:23
    create: /var/home/ian/src/zig/lib/std/Build/Step/Options.zig:26:23
    addOptions: /var/home/ian/src/zig/lib/std/Build.zig:635:24
    build: /var/home/ian/.cache/zig/p/12204e2334e652e8188f2298d4b29d03d78e6d101b6b231f0b35c7e7ad137f3be3b9/build.zig:49:32
    runBuild__anon_15700: /var/home/ian/src/zig/lib/std/Build.zig:2074:27
    dependencyInner__anon_15134: /var/home/ian/src/zig/lib/std/Build.zig:2055:29
    dependency__anon_14641: /var/home/ian/src/zig/lib/std/Build.zig:1912:35
    build: /var/home/ian/tmp/bad-zig-project/build.zig:92:34
    runBuild__anon_8989: /var/home/ian/src/zig/lib/std/Build.zig:2074:27
    main: /var/home/ian/src/zig/lib/compiler/build_runner.zig:310:29
    callMain: /var/home/ian/src/zig/lib/std/start.zig:511:32
    callMainWithArgs: /var/home/ian/src/zig/lib/std/start.zig:469:12
    posixCallMainAndExit: /var/home/ian/src/zig/lib/std/start.zig:425:20
    _start: /var/home/ian/src/zig/lib/std/start.zig:338:40

This is pointing at code in std.Build.Step.Options as the source of the error, but that's not where the error is actually being caused. This may be related to #18900.