Preserves interpreting multi-line strings as a single value for exclude in TOML files

docs/source/config_file.rst

@@ -214,6 +214,35 @@ section of the command line docs.
 
     This option may only be set in the global section (``[mypy]``).
 
+    .. note::
+
+       Note that the TOML equivalent differs slightly. It can be either a single string
+       (including a multi-line string) -- which is treated as a single regular
+       expression -- or an array of such strings. The following TOML examples are
+       equivalent to the above INI example.
+
+       Array of strings:
+
+       .. code-block:: toml
+
+          [tool.mypy]
+          exclude = [
+            "^file1\\.py$",  # TOML's double-quoted strings require escaping backslashes
+            '^file2\.py$',  # but TOML's single-quoted strings do not
+          ]
+
+       A single, multi-line string:
+
+       .. code-block:: toml
+
+          [tool.mypy]
+          exclude = '''(?x)(
+              ^file1\.py$
+              |^file2\.py$,
+          )'''
+
+       See :ref:`using-a-pyproject-toml`.
+
 .. confval:: namespace_packages
 
     :type: boolean
@@ -907,6 +936,8 @@ These options may only be set in the global section (``[mypy]``).
     Controls how much debug output will be generated.  Higher numbers are more verbose.
 
 
+.. _using-a-pyproject-toml:
+
 Using a pyproject.toml file
 ***************************
 
@@ -965,6 +996,10 @@ of your repo (or append it to the end of an existing ``pyproject.toml`` file) an
     python_version = "2.7"
     warn_return_any = true
     warn_unused_configs = true
+    exclude = [
+        '^file1\.py$',  # TOML literal string (single-quotes, no escaping necessary)
+        "^file2\\.py$",  # TOML basic string (double-quotes, backslash and other characters need escaping)
+    ]
 
     # mypy per-module options:
 

mypy/config_parser.py

@@ -57,6 +57,12 @@ def expand_path(path: str) -> str:
     return os.path.expandvars(os.path.expanduser(path))
 
 
+def str_or_array_as_list(v: Union[str, Sequence[str]]) -> List[str]:
+    if isinstance(v, str):
+        return [v.strip()] if v.strip() else []
+    return [p.strip() for p in v if p.strip()]
+
+
 def split_and_match_files_list(paths: Sequence[str]) -> List[str]:
     """Take a list of files/directories (with support for globbing through the glob library).
 
@@ -143,6 +149,7 @@ def check_follow_imports(choice: str) -> str:
     'disable_error_code': try_split,
     'enable_error_code': try_split,
     'package_root': try_split,
+    'exclude': str_or_array_as_list,
 })
 
 

test-data/unit/cmdline.pyproject.test

@@ -80,3 +80,48 @@ def g(a: int) -> int:
 [out]
 pyproject.toml: toml config file contains [[tool.mypy.overrides]] sections with conflicting values. Module 'x' has two different values for 'disallow_untyped_defs'
 == Return code: 0
+
+[case testMultilineLiteralExcludePyprojectTOML]
+# cmd: mypy x
+[file pyproject.toml]
+\[tool.mypy]
+exclude = '''(?x)(
+    (^|/)[^/]*skipme_\.py$
+    |(^|/)_skipme[^/]*\.py$
+)'''
+[file x/__init__.py]
+i: int = 0
+[file x/_skipme_please.py]
+This isn't even syntatically valid!
+[file x/please_skipme_.py]
+Neither is this!
+
+[case testMultilineBasicExcludePyprojectTOML]
+# cmd: mypy x
+[file pyproject.toml]
+\[tool.mypy]
+exclude = """(?x)(
+    (^|/)[^/]*skipme_\\.py$
+    |(^|/)_skipme[^/]*\\.py$
+)"""
+[file x/__init__.py]
+i: int = 0
+[file x/_skipme_please.py]
+This isn't even syntatically valid!
+[file x/please_skipme_.py]
+Neither is this!
+
+[case testSequenceExcludePyprojectTOML]
+# cmd: mypy x
+[file pyproject.toml]
+\[tool.mypy]
+exclude = [
+    '(^|/)[^/]*skipme_\.py$',  # literal (no escaping)
+    "(^|/)_skipme[^/]*\\.py$",  # basic (backslash needs escaping)
+]
+[file x/__init__.py]
+i: int = 0
+[file x/_skipme_please.py]
+This isn't even syntatically valid!
+[file x/please_skipme_.py]
+Neither is this!