pyxtest: replace numerical error values with BadValue, etc.

Let's use human-readable variables for this.

Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/2216>

test/pyxtest/test_randr.py

@@ -7,7 +7,7 @@ import struct
 import pytest
 
 from proto import randr
-from xclient import Extension, X11Error, X11Reply
+from xclient import BadIDChoice, BadLength, Extension, X11Error, X11Reply
 
 
 def _get_first_output(xclient, opcode):
@@ -179,8 +179,8 @@ class TestRandROutputProperty:
         # server tries to allocate 4 GB, failing with BadAlloc (11)
         # instead.
         assert isinstance(resp, X11Error), f"Expected an error, got {resp}"
-        assert resp.error_code == 16, (
-            f"Expected BadLength (16), got error code {resp.error_code} - "
+        assert resp.error_code == BadLength, (
+            f"Expected BadLength ({BadLength}), got error code {resp.error_code} - "
             f"integer truncation not caught by length check"
         )
 
@@ -305,6 +305,6 @@ class TestRandRCreateLease:
         # Without the fix: BadIDChoice (error code 14).
         # With the fix: either success or some other error.
         if isinstance(resp, X11Error):
-            assert resp.error_code != 14, (
-                "CreateLease returned BadIDChoice (error 14) - lid not byte-swapped"
+            assert resp.error_code != BadIDChoice, (
+                "CreateLease returned BadIDChoice - lid not byte-swapped"
             )

test/pyxtest/test_xi.py

@@ -7,7 +7,7 @@ import struct
 import pytest
 
 from proto import xi
-from xclient import Extension, X11Error, X11Reply
+from xclient import BadLength, BadValue, Extension, X11Error, X11Reply
 
 
 @pytest.fixture
@@ -116,8 +116,8 @@ class TestXIPassiveGrab:
         )
         # The fix returns BadValue (error code 2)
         assert isinstance(resp, X11Error), f"Expected an error reply, got {resp}"
-        assert resp.error_code == 2, (
-            f"Expected BadValue (2), got error code {resp.error_code}"
+        assert resp.error_code == BadValue, (
+            f"Expected BadValue ({BadValue}), got error code {resp.error_code}"
         )
 
 
@@ -168,8 +168,8 @@ class TestXIChangeProperty:
         # server tries to allocate 4 GB, failing with BadAlloc (11)
         # instead.
         assert isinstance(resp, X11Error), f"Expected an error, got {resp}"
-        assert resp.error_code == 16, (
-            f"Expected BadLength (16), got error code {resp.error_code} - "
+        assert resp.error_code == BadLength, (
+            f"Expected BadLength ({BadLength}), got error code {resp.error_code} - "
             f"integer truncation not caught by length check"
         )
 
@@ -385,7 +385,7 @@ class TestXIChangeDeviceControl:
         # With the fix: either a reply (success) or BadMatch (device
         # doesn't support resolution control), but NOT BadValue.
         if isinstance(resp, X11Error):
-            assert resp.error_code != 2, (
-                "ChangeDeviceControl returned BadValue (error 2) - "
+            assert resp.error_code != BadValue, (
+                "ChangeDeviceControl returned BadValue - "
                 "resolution values not byte-swapped"
             )

test/pyxtest/test_xkb.py

@@ -8,7 +8,7 @@ import time
 import pytest
 
 from proto import xkb
-from xclient import X11Error, X11Reply
+from xclient import BadLength, BadMatch, BadValue, X11Error, X11Reply
 
 
 @pytest.fixture
@@ -155,7 +155,7 @@ class TestXkbSetMapOverflows:
         # error code 0x25 in the resource_id.  Without the fix, the
         # wire pointer advances past the buffer and a later check
         # returns BadLength (16).
-        bad_value_errors = [e for e in errors if e.error_code == 2]
+        bad_value_errors = [e for e in errors if e.error_code == BadValue]
         assert bad_value_errors, (
             "SetMap with totalActs=0 but nonzero per-key action counts "
             "was not rejected with BadValue - server is missing the "
@@ -213,8 +213,8 @@ class TestXkbSetGeometry:
 
         assert xserver.is_alive, "Server crashed - truncated sections in SetGeometry"
         assert isinstance(resp, X11Error), f"Expected an error, got {resp}"
-        assert resp.error_code == 16, (
-            f"Expected BadLength (16), got error code {resp.error_code} - "
+        assert resp.error_code == BadLength, (
+            f"Expected BadLength ({BadLength}), got error code {resp.error_code} - "
             f"missing bounds check in SetGeometry section parsing"
         )
 
@@ -263,7 +263,7 @@ class TestXkbSetGeometry:
         resps = xclient.flush_responses(timeout=0.5)
         errors = [r for r in resps if isinstance(r, X11Error)]
 
-        bad_value_errors = [e for e in errors if e.error_code == 2]
+        bad_value_errors = [e for e in errors if e.error_code == BadValue]
         assert bad_value_errors, (
             f"SetGeometry with {which_ndx}=200 nOutlines=1 was not rejected "
             f"with BadValue - server is missing the {which_ndx} bounds check"
@@ -320,7 +320,7 @@ class TestXkbSetGeometry:
         # With the fix, we get BadMatch (8) from the color index check.
         # Without the fix, the OOB access happens silently and the
         # request succeeds (no error), so valgrind catches it.
-        match_errors = [e for e in errors if e.error_code == 8]
+        match_errors = [e for e in errors if e.error_code == BadMatch]
         assert match_errors, (
             f"SetGeometry with {which_color}ColorNdx=nColors was not rejected with "
             f"BadMatch - server is missing the off-by-one check"
@@ -384,7 +384,7 @@ class TestXkbSetGeometry:
         # With the fix, we get BadMatch (8) from the rowUnder >= num_rows check.
         # Without the fix, rowUnder == num_rows passes the '>' check and
         # the OOB access happens in XkbAddGeomOverlayRow().
-        match_errors = [e for e in errors if e.error_code == 8]
+        match_errors = [e for e in errors if e.error_code == BadMatch]
         assert match_errors, (
             "SetGeometry with rowUnder=1 num_rows=1 was not rejected with "
             "BadMatch - server is missing the off-by-one check"

test/pyxtest/xclient.py

@@ -69,6 +69,26 @@ class Extension(StrEnum):
     XVIDEO_MC = "XVideo-MotionCompensation"
 
 
+# X11 core protocol error codes (from X.h)
+BadRequest = 1
+BadValue = 2
+BadWindow = 3
+BadPixmap = 4
+BadAtom = 5
+BadCursor = 6
+BadFont = 7
+BadMatch = 8
+BadDrawable = 9
+BadAccess = 10
+BadAlloc = 11
+BadColor = 12
+BadGC = 13
+BadIDChoice = 14
+BadName = 15
+BadLength = 16
+BadImplementation = 17
+
+
 @dataclass
 class X11Error:
     """An X11 error reply from the server."""