32da32ca66
- library/modules/platform/sdl3.sx: SdlPlatform impl wrapping SDL3 init,
GL context, event pump, swap. run_frame_loop owns the loop: while loop
on desktop, emscripten_set_main_loop on WASM. Registers an event-watch
that re-invokes the frame closure during macOS modal resize-drag so
content keeps rendering at the new size. safe_insets / keyboard /
show_keyboard / hide_keyboard are no-ops (these targets have no soft
keyboard).
Two compiler bug repros uncovered during the refactor:
- examples/issue-0020.sx: global `Foo = .{}` zero-initializes, ignoring
struct field defaults. Local `Foo = .{}` correctly applies defaults.
Workaround: set fields explicitly in an init method or heap-allocate
the value.
- examples/issue-0021.sx: an enclosing function's return type bleeds
into `xx`'s target type inside an `if-then-else` expression on the
RHS of a struct-field assignment. The same expression in a `-> void`
function produces the right value; in a `-> bool` function it
silently produces 0. Bit the SX Chess game's dpi_scale calc inside
`SdlPlatform.init` (returns bool), making all text labels render
invisibly on retina. Workaround: hoist each `xx` cast into its own
f32 local.
Regression gate: 50/50 examples pass, macOS chess game runs at ~2700fps
(close to the pre-refactor 2900 baseline), WASM build still emits a
working .html/.js/.wasm/.data quad.
55 lines
1.7 KiB
Plaintext
55 lines
1.7 KiB
Plaintext
// issue-0020: Global `Foo = .{}` zero-initializes, ignoring field defaults
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//
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// Struct field defaults declared via `field: T = expr;` are honored when the
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// struct is constructed at function-local scope, but are silently dropped
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// when the struct is declared at module scope with `= .{}`.
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//
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// Repro:
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//
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// Foo :: struct {
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// running: bool = true; // default
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// }
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//
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// g_foo : Foo = .{}; // global → g_foo.running == false (BUG)
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//
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// main :: () {
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// l_foo : Foo = .{}; // local → l_foo.running == true (correct)
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// }
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//
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// Surface bites:
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//
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// - In the SX Chess game, the SDL3 platform backend stores a `running: bool
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// = true` field on `SdlPlatform`. With `g_plat : SdlPlatform = .{};` the
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// main loop's `while self.running { ... }` exits immediately because
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// `running` was zero-initialized despite the field default.
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// - Workaround: assign defaults explicitly in the type's `init` method, or
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// spell every field out at the global construction site:
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// g_plat : SdlPlatform = .{ running = true };
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//
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// Likely cause: the globals path emits an LLVM ConstantAggregateZero (or
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// memset-to-zero) for the initializer, skipping the per-field default-expr
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// lowering used for local declarations.
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//
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// This file is a runnable repro: locals print "running=true", globals print
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// "running=false".
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#import "modules/std.sx";
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Foo :: struct {
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running: bool = true;
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x: s32 = 42;
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}
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g_foo : Foo = .{};
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main :: () -> void {
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out("global running=");
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out(if g_foo.running then "true" else "false");
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out("\n");
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l_foo : Foo = .{};
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out("local running=");
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out(if l_foo.running then "true" else "false");
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out("\n");
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}
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