Fix #2549: block config.<name> assignments (#2585)

* Fix #2549: block config.<name> assignments

This commit blocks `config.<param> = <value>` assignments as they should be done via `config.<param>.value = <value>`
instead.

* Update config.py

* add .value

DEVELOPING.md

@@ -89,7 +89,7 @@ Here's a small snippet of the actual test:
 ```python
 def test_hexdump(start_binary):
     start_binary(BINARY)
-    pwndbg.config.hexdump_group_width = -1
+    pwndbg.config.hexdump_group_width.value = -1
 
     gdb.execute("set hexdump-byte-separator")
     stack_addr = pwndbg.aglib.regs.rsp - 0x100

pwndbg/lib/config.py

@@ -208,3 +208,8 @@ class Config:
             return self.params[name]
         else:
             raise AttributeError(f"'Config' object has no attribute '{name}'")
+
+    def __setattr__(self, attr, val):
+        if attr in ("params", "triggers"):
+            return super().__setattr__(attr, val)
+        raise AttributeError("Use config.<param>.value to set value of a parameter")

tests/gdb-tests/tests/test_hexdump.py

@@ -13,7 +13,7 @@ BINARY = tests.binaries.get("reference-binary.out")
 
 
 def run_tests(stack, use_big_endian, expected):
-    pwndbg.config.hexdump_group_use_big_endian = use_big_endian
+    pwndbg.config.hexdump_group_use_big_endian.value = use_big_endian
 
     # Put some data onto the stack
     pwndbg.aglib.memory.write(stack, cyclic(0x100))
@@ -35,7 +35,7 @@ def run_tests(stack, use_big_endian, expected):
 
 def test_hexdump(start_binary):
     start_binary(BINARY)
-    pwndbg.config.hexdump_group_width = -1
+    pwndbg.config.hexdump_group_width.value = -1
 
     # TODO: Setting theme options with Python isn't working
     gdb.execute("set hexdump-byte-separator")