Fix a bug with subscript assign (#191)

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Change Log
 
+## [unpublished]
+
+- Fixed
+  - Fixed a bug where assigning a dict value (such as `abc['something'] = 123`)
+    would result in EdgeCaseError
+
 ## [0.5.12] - 2024-12-15
 
 - Changed

pydoclint/utils/arg.py

@@ -226,14 +226,22 @@ def fromAstAssign(cls, astAssign: ast.Assign) -> 'ArgList':
                     infoList.append(Arg(name=item.id, typeHint=''))
             elif isinstance(target, ast.Name):  # such as `a = 1` or `a = b = 2`
                 infoList.append(Arg(name=target.id, typeHint=''))
-            elif isinstance(target, ast.Attribute):  # e.g., uvw.xyz = 1
-                unparsedTarget: str | None = unparseName(target)
-                assert unparsedTarget is not None  # to help mypy understand type
-                infoList.append(Arg(name=unparsedTarget, typeHint=''))
             else:
-                raise EdgeCaseError(
-                    f'astAssign.targets[{i}] is of type {type(target)}'
-                )
+                try:  # we may not know all potential cases, so we use try/catch
+                    unparsedTarget: str | None = unparseName(target)
+                    assert unparsedTarget is not None  # to help mypy understand type
+                    infoList.append(Arg(name=unparsedTarget, typeHint=''))
+                except Exception as ex:
+                    lineRange: str = (
+                        f'in Line {astAssign.lineno}'
+                        if astAssign.lineno == astAssign.end_lineno
+                        else f'in Lines {astAssign.lineno}-{astAssign.end_lineno}'
+                    )
+                    msg: str = (
+                        f'Edge case encountered {lineRange}.'
+                        f' astAssign.targets[{i}] is of type {type(target)}.'
+                    )
+                    raise EdgeCaseError(msg) from ex
 
         return ArgList(infoList=infoList)
 

tests/data/edge_cases/18_assign_to_subscript/case.py

@@ -0,0 +1,14 @@
+# This comes from the pip repository:
+# https://github.com/pypa/pip/blob/3b91f42e461de3f23e9bed46a8c5695435f930fb/src/pip/_internal/cli/cmdoptions.py#L110-L114
+# and it was encountered by a user in https://github.com/jsh9/pydoclint/issues/190
+#
+# It's just supposed to pass without bugs and violations.
+# (The previous buggy implementation would raise EdgeCaseError when parsing
+# this code.)
+
+
+class PipOption(Option):
+    TYPES = Option.TYPES + ('path', 'package_name')
+    TYPE_CHECKER = Option.TYPE_CHECKER.copy()
+    TYPE_CHECKER['package_name'] = _package_name_option_check
+    TYPE_CHECKER['path'] = _path_option_check

tests/test_main.py

@@ -1530,6 +1530,7 @@ def testNonAscii() -> None:
                 'correctly document class attributes.)',
             ],
         ),
+        ('18_assign_to_subscript/case.py', {}, []),
     ],
 )
 def testEdgeCases(