mavgen_cpp11: fix IndexError when an enum entry is a prefix of the enum name

generator/mavgen_cpp11.py

@@ -301,7 +301,10 @@ def enum_remove_prefix(prefix, s):
     sl = s.split('_')
 
     for i in range(len(pl)):
-        if pl[i] == sl[0]:
+        # keep at least one component, so that an entry whose name is a
+        # prefix of the enum name (e.g. SOME_ENUM in SOME_ENUM_NAME) does
+        # not end up with an empty name
+        if len(sl) > 1 and pl[i] == sl[0]:
             sl = sl[1:]
         else:
             break

tests/test_mavgen_cpp11.py

@@ -0,0 +1,64 @@
+#!/usr/bin/env python3
+"""
+Tests for the C++11 generator.
+"""
+
+from pathlib import Path
+import shutil
+import sys
+
+try:
+    from pymavlink.generator import mavgen
+    from pymavlink.generator import mavgen_cpp11
+except ModuleNotFoundError:
+    sys.path.insert(0, str(Path(__file__).resolve().parents[1]))
+    from generator import mavgen
+    from generator import mavgen_cpp11
+
+
+def test_enum_remove_prefix():
+    assert mavgen_cpp11.enum_remove_prefix("MAV_CMD", "MAV_CMD_NAV_WAYPOINT") == "NAV_WAYPOINT"
+    assert mavgen_cpp11.enum_remove_prefix("MAV_FRAME", "MAV_FRAME_GLOBAL") == "GLOBAL"
+    # a remainder starting with a digit gets the last prefix component back
+    assert mavgen_cpp11.enum_remove_prefix("MAV_SYS_STATUS_SENSOR", "MAV_SYS_STATUS_SENSOR_3D_GYRO") == "SENSOR_3D_GYRO"
+    # an entry whose name is a prefix of the enum name must keep its last component
+    assert mavgen_cpp11.enum_remove_prefix("SOME_ENUM_NAME", "SOME_ENUM") == "ENUM"
+    assert mavgen_cpp11.enum_remove_prefix("SOME_ENUM_NAME", "SOME_ENUM_NAME") == "NAME"
+    assert mavgen_cpp11.enum_remove_prefix("SOME_ENUM_NAME", "SOME") == "SOME"
+
+
+def test_cpp11_generator_enum_entry_is_prefix_of_enum_name(tmp_path):
+    xml_filepath = tmp_path / "test.xml"
+    xml_filepath.write_text("""<?xml version="1.0"?>
+<mavlink>
+  <version>3</version>
+  <enums>
+    <enum name="SOME_ENUM_NAME">
+      <entry value="0" name="SOME_ENUM"/>
+      <entry value="1" name="SOME_ENUM_NAME_VALUE"/>
+    </enum>
+  </enums>
+  <messages>
+  </messages>
+</mavlink>
+""")
+    output_dir = Path(__file__).resolve().parents[1] / ".tmp" / "cpp11-generator"
+    shutil.rmtree(output_dir, ignore_errors=True)
+    output_dir.mkdir(parents=True, exist_ok=True)
+
+    ok = mavgen.mavgen(
+        mavgen.Opts(
+            output=str(output_dir),
+            language="C++11",
+            wire_protocol="2.0",
+            validate=False,
+        ),
+        [str(xml_filepath)],
+    )
+
+    assert ok is True
+
+    header = (output_dir / "test" / "test.hpp").read_text(encoding="utf-8")
+    assert "enum class SOME_ENUM_NAME" in header
+    assert "    ENUM=0," in header
+    assert "    VALUE=1," in header