Error when getting an unset context without a default (#101)

Co-authored-by: centau <83140718+centau@users.noreply.github.com>

docs/api/reactivity-utility.md

@@ -131,6 +131,8 @@ Creates a new context.
 
     Calling `context()` returns a new context function.
     Call this function with no arguments to get the context value.
+    If no context is set, the default value is returned, or an error is thrown
+    if no default was given.
     Call this function with a value and a function to create a new context with
     the given value.
 

src/context.luau

@@ -40,7 +40,7 @@ local function context<T>(...: T): Context<T>
                 return (if value ~= nil_symbol then value else nil) :: T
             end
 
-            if has_default ~= nil then
+            if has_default then
                 return default_value
             else
                 error("attempt to get context when no context is set and no default context is set", 0)

test/tests.luau

@@ -2828,6 +2828,16 @@ TEST("context()", function()
             end)
         end)
     end
+
+    do CASE "get context without default"
+        local ctx = context()
+
+        CHECK(not pcall(ctx))
+
+        root(function()
+            CHECK(not pcall(ctx))
+        end)
+    end
 end)
 
 TEST("nested effects cases", function()