Preserve real parse diagnostics instead of the generic section wrapper

area_reader/__init__.py

@@ -335,8 +335,10 @@ def load_sections(self):
 				logger.info("Processing section %s" % section_name)
 				try:
 					readers[section_name]()
-				except Exception:
-					self.parse_fail("Error reading section %r" % section_name)
+				except ParseError:
+					raise
+				except Exception as error:
+					self.parse_fail("Error reading section %r: %r" % (section_name, error))
 
 	def load_mobprogs(self):
 		while True:
@@ -1944,8 +1946,10 @@ def load_sections(self):
 				logger.info("Processing section %s" % section_name)
 				try:
 					reader()
-				except Exception:
-					self.parse_fail("Error reading section %r" % section_name)
+				except ParseError:
+					raise
+				except Exception as error:
+					self.parse_fail("Error reading section %r: %r" % (section_name, error))
 
 	def read_area_metadata(self):
 		self.area.name = self.read_string()
@@ -1999,7 +2003,7 @@ def load_smaug_vnum_section(self, section_object_type):
 				break
 			if self.current_char != '#':
 				self.parse_fail("Expected # got %s" % self.current_char)
-			next_char = self.data[self.index + 1]
+			next_char = self.data[self.index + 1:self.index + 2]
 			if not (next_char.isdigit() or next_char == '-'):
 				break
 			vnum = self.read_vnum()
@@ -2098,7 +2102,7 @@ def load_swr_vnum_section(self, section_object_type):
 				break
 			if self.current_char != '#':
 				self.parse_fail("Expected # got %s" % self.current_char)
-			next_char = self.data[self.index + 1]
+			next_char = self.data[self.index + 1:self.index + 2]
 			if not (next_char.isdigit() or next_char == '-'):
 				break
 			vnum = self.read_vnum()
@@ -2843,7 +2847,10 @@ def read_record_header(self):
 			self.index += 1
 		if self.current_char == '~':
 			self.index += 1
-		return int(token)
+		try:
+			return int(token)
+		except ValueError:
+			self.parse_fail("Expected numeric record header, got %r" % token)
 
 	def read_int_list(self):
 		line = self.read_line().strip()

test_error_reporting.py

@@ -0,0 +1,71 @@
+"""Regression tests for issue #12: section readers must not hide the real diagnostic."""
+
+from pathlib import Path
+
+import pytest
+
+import area_reader
+
+
+def write_area(tmp_path: Path, text: str, name: str = "broken.are") -> Path:
+	path = tmp_path / name
+	path.write_text(text, encoding="latin-1")
+	return path
+
+
+def test_rom_section_error_keeps_the_specific_parse_message(tmp_path):
+	path = write_area(tmp_path, "#MOBILES\n#3000\nguard~\nA guard\n")
+	reader = area_reader.RomAreaFile(path)
+
+	with pytest.raises(area_reader.ParseError) as caught:
+		reader.load_sections()
+
+	assert "Unterminated string" in str(caught.value)
+	assert "Error reading section" not in str(caught.value)
+
+
+def test_smaug_section_error_keeps_the_specific_parse_message(tmp_path):
+	path = write_area(tmp_path, "#MOBILES\n#3000\nguard~\nA guard\n")
+	reader = area_reader.SmaugAreaFile(path)
+
+	with pytest.raises(area_reader.ParseError) as caught:
+		reader.load_sections()
+
+	assert "Unterminated string" in str(caught.value)
+	assert "Error reading section" not in str(caught.value)
+
+
+def test_non_parse_errors_are_reported_with_the_original_error(tmp_path, monkeypatch):
+	path = write_area(tmp_path, "#MOBILES\n#0\n\n#$\n")
+	reader = area_reader.RomAreaFile(path)
+
+	def exploding_reader():
+		raise RuntimeError("internal boom")
+
+	monkeypatch.setattr(reader, "load_mobiles", exploding_reader)
+
+	with pytest.raises(area_reader.ParseError) as caught:
+		reader.load_sections()
+
+	assert "Error reading section 'mobiles'" in str(caught.value)
+	assert "internal boom" in str(caught.value)
+
+
+@pytest.mark.parametrize("reader_class", ["SmaugAreaFile", "SwrAreaFile"])
+def test_vnum_section_tolerates_a_trailing_hash_at_end_of_file(tmp_path, reader_class):
+	path = write_area(tmp_path, "#MOBILES\n#", name="trailing.are")
+	reader = getattr(area_reader, reader_class)(path)
+
+	reader.load_sections()
+
+	assert reader.area.mobs == {}
+
+
+def test_circle_record_header_rejects_a_non_numeric_vnum(tmp_path):
+	path = tmp_path / "broken.wld"
+	path.write_text("#\nname~\n", encoding="latin-1")
+	reader = area_reader.CircleAreaFile(tmp_path)
+	reader.open_circle_file(path)
+
+	with pytest.raises(area_reader.ParseError, match="Expected numeric record header"):
+		reader.read_record_header()