lint: ban comparing against undefined in Zig (#10288)

packages/bun-internal-test/src/banned.json

@@ -3,5 +3,9 @@
   "@import(\"root\").bun.": "Only import 'bun' once",
   "std.mem.indexOfAny": "Use bun.strings.indexAny or bun.strings.indexAnyComptime",
   "std.debug.print": "Don't let this be committed",
+  " == undefined": "This is by definition Undefined Behavior.",
+  " != undefined": "This is by definition Undefined Behavior.",
+  "undefined == ": "This is by definition Undefined Behavior.",
+  "undefined != ": "This is by definition Undefined Behavior.",
   "": ""
 }

src/bun.zig

@@ -3101,6 +3101,16 @@ pub fn assert(value: bool) callconv(callconv_inline) void {
     }
 }
 
+/// This has no effect on the real code but capturing 'a' and 'b' into parameters makes assertion failures much easier inspect in a debugger.
+pub inline fn assert_eql(a: anytype, b: anytype) void {
+    return assert(a == b);
+}
+
+/// This has no effect on the real code but capturing 'a' and 'b' into parameters makes assertion failures much easier inspect in a debugger.
+pub inline fn assert_neql(a: anytype, b: anytype) void {
+    return assert(a != b);
+}
+
 pub inline fn unsafeAssert(condition: bool) void {
     if (!condition) {
         unreachable;

src/install/semver.zig

@@ -47,22 +47,6 @@ pub const String = extern struct {
         };
     }
 
-    pub inline fn init(
-        buf: string,
-        in: string,
-    ) String {
-        if (comptime Environment.isDebug) {
-            const out = realInit(buf, in);
-            if (!out.isInline()) {
-                assert(@as(u64, @bitCast(out.slice(buf)[0..8].*)) != undefined);
-            }
-
-            return out;
-        } else {
-            return realInit(buf, in);
-        }
-    }
-
     pub const Formatter = struct {
         str: *const String,
         buf: string,
@@ -150,7 +134,7 @@ pub const String = extern struct {
         }
     };
 
-    fn realInit(
+    pub fn init(
         buf: string,
         in: string,
     ) String {