Commit 51be575745adfe21a5367f206c156f2d589ad436 | zig

author	LemonBoy <thatlemon@gmail.com> 2021-10-17 15:52:19+02:00
committer	Andrew Kelley <andrew@ziglang.org> 2021-10-17 16:06:40-04:00
log	51be575745adfe21a5367f206c156f2d589ad436
tree	a888b7e8eb55a0c91c7686ef5b0570c8085bc11d
parent	98a37dfb23202e3f56e1596a19be3fa563f65eeb

std: Fix endless loop in fmt impl

Apparently there's a stage1 bug that may sometimes lead to an endless
loop being generated when unrolling the fmt impl.

Closes #9961

1 files changed, 16 insertions(+), 14 deletions(-)

lib
- std
  - fmt.zig

lib/std/fmt.zig+16-14

 @@ -295,21 +295,21 @@ pub fn format(
         }
         // Parse the width parameter
-        options.width = init: {
+        options.width = comptime init: {
-            if (comptime parser.maybe('[')) {
+            if (parser.maybe('[')) {
-                const arg_name = comptime parser.until(']');
+                const arg_name = parser.until(']');
-                if (!comptime parser.maybe(']')) {
+                if (!parser.maybe(']')) {
                     @compileError("Expected closing ]");
                 }
-                const index = comptime meta.fieldIndex(ArgsType, arg_name) orelse
+                const index = meta.fieldIndex(ArgsType, arg_name) orelse
                     @compileError("No argument with name '" ++ arg_name ++ "'");
-                const arg_index = comptime arg_state.nextArg(index);
+                const arg_index = arg_state.nextArg(index);
                 break :init @field(args, fields_info[arg_index].name);
             } else {
-                break :init comptime parser.number();
+                break :init parser.number();
             }
         };
 @@ -321,21 +321,21 @@ pub fn format(
         }
         // Parse the precision parameter
-        options.precision = init: {
+        options.precision = comptime init: {
-            if (comptime parser.maybe('[')) {
+            if (parser.maybe('[')) {
-                const arg_name = comptime parser.until(']');
+                const arg_name = parser.until(']');
-                if (!comptime parser.maybe(']')) {
+                if (!parser.maybe(']')) {
                     @compileError("Expected closing ]");
                 }
-                const arg_i = comptime meta.fieldIndex(ArgsType, arg_name) orelse
+                const arg_i = meta.fieldIndex(ArgsType, arg_name) orelse
                     @compileError("No argument with name '" ++ arg_name ++ "'");
-                const arg_to_use = comptime arg_state.nextArg(arg_i);
+                const arg_to_use = arg_state.nextArg(arg_i);
                 break :init @field(args, fields_info[arg_to_use].name);
             } else {
-                break :init comptime parser.number();
+                break :init parser.number();
             }
         };
 @@ -2576,6 +2576,8 @@ test "runtime width specifier" {
     var width: usize = 9;
     try expectFmt("~~hello~~", "{s:~^[1]}", .{ "hello", width });
     try expectFmt("~~hello~~", "{s:~^[width]}", .{ .string = "hello", .width = width });
+    try expectFmt("    hello", "{s:[1]}", .{ "hello", width });
+    try expectFmt("42     hello", "{d} {s:[2]}", .{ 42, "hello", width });
 }
 test "runtime precision specifier" {