avoid a trycatch in tryparse(::Type{UUID}, ...) (#37696)

Author: KristofferC

base/uuid.jl

@@ -32,56 +32,55 @@ end
 UInt128(u::UUID) = u.value
 
 let
-@noinline throw_malformed_uuid(s) = throw(ArgumentError("Malformed UUID string: $(repr(s))"))
 @inline function uuid_kernel(s, i, u)
     _c = UInt32(@inbounds codeunit(s, i))
     d = __convert_digit(_c, UInt32(16))
-    d >= 16 && throw_malformed_uuid(s)
+    d >= 16 && return nothing
     u <<= 4
-    u | d
+    return u | d
 end
 
-global UUID
-function UUID(s::AbstractString)
+function Base.tryparse(::Type{UUID}, s::AbstractString)
     u = UInt128(0)
-    ncodeunits(s) != 36 && throw_malformed_uuid(s)
+    ncodeunits(s) != 36 && return nothing
     for i in 1:8
         u = uuid_kernel(s, i, u)
+        u === nothing && return nothing
     end
-    @inbounds codeunit(s, 9) == UInt8('-') || @goto error
+    @inbounds codeunit(s, 9) == UInt8('-') || return nothing
     for i in 10:13
         u = uuid_kernel(s, i, u)
+        u === nothing && return nothing
     end
-    @inbounds codeunit(s, 14) == UInt8('-') || @goto error
+    @inbounds codeunit(s, 14) == UInt8('-') || return nothing
     for i in 15:18
         u = uuid_kernel(s, i, u)
+        u === nothing && return nothing
     end
-    @inbounds codeunit(s, 19) == UInt8('-') || @goto error
+    @inbounds codeunit(s, 19) == UInt8('-') || return nothing
     for i in 20:23
         u = uuid_kernel(s, i, u)
+        u === nothing && return nothing
     end
-    @inbounds codeunit(s, 24) == UInt8('-') || @goto error
+    @inbounds codeunit(s, 24) == UInt8('-') || return nothing
     for i in 25:36
         u = uuid_kernel(s, i, u)
+        u === nothing && return nothing
     end
     return Base.UUID(u)
-    @label error
-    throw_malformed_uuid(s)
 end
 end
 
-parse(::Type{UUID}, s::AbstractString) = UUID(s)
-function tryparse(::Type{UUID}, s::AbstractString)
-    try
-        return parse(UUID, s)
-    catch e
-        if isa(e, ArgumentError)
-            return nothing
-        end
-        rethrow(e)
+let
+    @noinline throw_malformed_uuid(s) = throw(ArgumentError("Malformed UUID string: $(repr(s))"))
+    function Base.parse(::Type{UUID}, s::AbstractString)
+        uuid = tryparse(UUID, s)
+        return uuid === nothing ? throw_malformed_uuid(s) : uuid
     end
 end
 
+UUID(s::AbstractString) = parse(UUID, s)
+
 let groupings = [36:-1:25; 23:-1:20; 18:-1:15; 13:-1:10; 8:-1:1]
     global string
     function string(u::UUID)