Select the most appropriate string representation based on heuristic

setup.cfg

@@ -62,14 +62,14 @@ exclude =
 full =
     importlib-metadata; python_version<"3.8"
     configupdater>=3.0.1,<4
-    tomlkit>=0.9.2,<2
+    tomlkit>=0.10.0,<2
     # atoml @ git+https://github.com/abravalheri/atoml@table-common-ancestor#egg=atoml
 lite =
     importlib-metadata; python_version<"3.8"
     tomli-w>=0.4.0,<2
 all =
     configupdater>=3.0.1,<4
-    tomlkit>=0.9.2,<2
+    tomlkit>=0.10.0,<2
     # atoml @ git+https://github.com/abravalheri/atoml@table-common-ancestor#egg=atoml
     tomli-w>=0.4.0,<2
 

src/ini2toml/drivers/full_toml.py

@@ -18,9 +18,10 @@
     item,
     loads,
     nl,
+    string,
     table,
 )
-from tomlkit.items import AoT, Array, InlineTable, Item, Table
+from tomlkit.items import AoT, Array, InlineTable, Item, String, Table
 from tomlkit.toml_document import TOMLDocument
 
 from ..errors import InvalidTOMLKey
@@ -59,6 +60,11 @@ def collapse(obj, root=False):
     return obj
 
 
+@collapse.register(str)
+def _collapse_string(obj: str) -> String:
+    return _string(obj)
+
+
 @collapse.register(Commented)
 def _collapse_commented(obj: Commented, root=False) -> Item:
     return create_item(obj.value_or(None), obj.comment)
@@ -235,7 +241,7 @@ def _convert_irepr_to_toml(irepr: IntermediateRepr, out: T) -> T:
 
 
 def create_item(value, comment):
-    obj = item(value)
+    obj = _item(value)
     if comment is not None:
         obj.comment(comment)
     return obj
@@ -291,3 +297,28 @@ def classify_list(seq: Sequence) -> Tuple[bool, int, int, bool, bool, int]:
         has_nl = has_nl or "\n" in elem_repr
 
     return is_aot, max_len, total_len, has_nl, has_nested, len(seq)
+
+
+def _item(obj) -> Item:
+    if isinstance(obj, str):
+        return _string(obj)
+
+    return item(obj)
+
+
+def _string(obj: str) -> String:
+    """Try to guess the best TOML representation for a string"""
+    multiline = "\n" in obj
+    single_line = "".join(x.strip().rstrip("\\") for x in obj.splitlines())
+    literal = '"' in obj or "\\" in single_line
+
+    if multiline and not obj.startswith("\n"):
+        # TOML will automatically strip an starting newline
+        # so let's add it, since it is better for reading
+        obj = "\n" + obj
+
+    try:
+        return string(obj, literal=literal, multiline=multiline)
+    except ValueError:
+        # Literal strings are not always possible
+        return string(obj, multiline=multiline)

tests/examples/django/pyproject.toml

@@ -29,7 +29,7 @@ dynamic = ["license", "version"]
 requires-python = ">=3.8"
 dependencies = [
     "asgiref >= 3.3.2",
-    "backports.zoneinfo; python_version<\"3.9\"",
+    'backports.zoneinfo; python_version<"3.9"',
     "sqlparse >= 0.2.2",
     "tzdata; sys_platform == 'win32'",
 ]

tests/examples/flask/pyproject.toml

@@ -79,10 +79,22 @@ source = [
 # B9 = bugbear opinions
 # ISC = implicit-str-concat
 select = "B, E, F, W, B9, ISC"
-ignore = "\n# slice notation whitespace, invalid\nE203\n# import at top, too many circular import fixes\nE402\n# line length, handled by bugbear B950\nE501\n# bare except, handled by bugbear B001\nE722\n# bin op line break, invalid\nW503"
+ignore = """
+# slice notation whitespace, invalid
+E203
+# import at top, too many circular import fixes
+E402
+# line length, handled by bugbear B950
+E501
+# bare except, handled by bugbear B001
+E722
+# bin op line break, invalid
+W503"""
 # up to 88 allowed by bugbear B950
 max-line-length = "80"
-per-file-ignores = "\n# __init__ module exports names\nsrc/flask/__init__.py: F401"
+per-file-ignores = """
+# __init__ module exports names
+src/flask/__init__.py: F401"""
 
 [tool.mypy]
 files = ["src/flask"]

tests/examples/pandas/pyproject.toml

@@ -80,19 +80,90 @@ parentdir_prefix = "pandas-"
 
 [tool.flake8]
 max-line-length = "88"
-ignore = "\n# space before : (needed for how black formats slicing)\nE203,\n# line break before binary operator\nW503,\n# line break after binary operator\nW504,\n# module level import not at top of file\nE402,\n# do not assign a lambda expression, use a def\nE731,\n# found modulo formatter (incorrect picks up mod operations)\nS001,\n# controversial\nB005,\n# controversial\nB006,\n# controversial\nB007,\n# controversial\nB008,\n# setattr is used to side-step mypy\nB009,\n# getattr is used to side-step mypy\nB010,\n# tests use assert False\nB011,\n# tests use comparisons but not their returned value\nB015,\n# false positives\nB301"
-exclude = "\ndoc/sphinxext/*.py,\ndoc/build/*.py,\ndoc/temp/*.py,\n.eggs/*.py,\nversioneer.py,\n# exclude asv benchmark environments from linting\nenv"
-per-file-ignores = "\n# private import across modules\npandas/tests/*:PDF020\n# pytest.raises without match=\npandas/tests/extension/*:PDF009\n# os.remove\ndoc/make.py:PDF008\n# import from pandas._testing\npandas/testing.py:PDF014"
+ignore = """
+# space before : (needed for how black formats slicing)
+E203,
+# line break before binary operator
+W503,
+# line break after binary operator
+W504,
+# module level import not at top of file
+E402,
+# do not assign a lambda expression, use a def
+E731,
+# found modulo formatter (incorrect picks up mod operations)
+S001,
+# controversial
+B005,
+# controversial
+B006,
+# controversial
+B007,
+# controversial
+B008,
+# setattr is used to side-step mypy
+B009,
+# getattr is used to side-step mypy
+B010,
+# tests use assert False
+B011,
+# tests use comparisons but not their returned value
+B015,
+# false positives
+B301"""
+exclude = """
+doc/sphinxext/*.py,
+doc/build/*.py,
+doc/temp/*.py,
+.eggs/*.py,
+versioneer.py,
+# exclude asv benchmark environments from linting
+env"""
+per-file-ignores = """
+# private import across modules
+pandas/tests/*:PDF020
+# pytest.raises without match=
+pandas/tests/extension/*:PDF009
+# os.remove
+doc/make.py:PDF008
+# import from pandas._testing
+pandas/testing.py:PDF014"""
 
 [tool.flake8-rst]
 max-line-length = "84"
-bootstrap = "\nimport numpy as np\nimport pandas as pd\n# avoiding error when importing again numpy or pandas\nnp\n# (in some cases we want to do it to show users)\npd"
-ignore = "\n# space before : (needed for how black formats slicing)\nE203,\n# module level import not at top of file\nE402,\n# line break before binary operator\nW503,\n# Classes/functions in different blocks can generate those errors\n# expected 2 blank lines, found 0\nE302,\n# expected 2 blank lines after class or function definition, found 0\nE305,\n# We use semicolon at the end to avoid displaying plot objects\n# statement ends with a semicolon\nE703,\n# comparison to none should be 'if cond is none:'\nE711,"
-exclude = "\ndoc/source/development/contributing_docstring.rst,\n# work around issue of undefined variable warnings\n# https://github.com/pandas-dev/pandas/pull/38837#issuecomment-752884156\ndoc/source/getting_started/comparison/includes/*.rst"
+bootstrap = """
+import numpy as np
+import pandas as pd
+# avoiding error when importing again numpy or pandas
+np
+# (in some cases we want to do it to show users)
+pd"""
+ignore = """
+# space before : (needed for how black formats slicing)
+E203,
+# module level import not at top of file
+E402,
+# line break before binary operator
+W503,
+# Classes/functions in different blocks can generate those errors
+# expected 2 blank lines, found 0
+E302,
+# expected 2 blank lines after class or function definition, found 0
+E305,
+# We use semicolon at the end to avoid displaying plot objects
+# statement ends with a semicolon
+E703,
+# comparison to none should be 'if cond is none:'
+E711,"""
+exclude = """
+doc/source/development/contributing_docstring.rst,
+# work around issue of undefined variable warnings
+# https://github.com/pandas-dev/pandas/pull/38837#issuecomment-752884156
+doc/source/getting_started/comparison/includes/*.rst"""
 
 [tool.codespell]
 ignore-words-list = "ba,blocs,coo,hist,nd,sav,ser"
-ignore-regex = "https://(\\w+\\.)+"
+ignore-regex = 'https://(\w+\.)+'
 
 [tool.coverage.run]
 branch = true
@@ -114,7 +185,7 @@ exclude_lines = [
     "pragma: no cover",
     # Don't complain about missing debug-only code:
     "def __repr__",
-    "if self\\.debug",
+    'if self\.debug',
     # Don't complain if tests don't hit defensive assertion code:
     "raise AssertionError",
     "raise NotImplementedError",

tests/examples/pluggy/pyproject.toml

@@ -32,7 +32,7 @@ classifiers = [
 urls = {Homepage = "https://github.com/pytest-dev/pluggy"}
 dynamic = ["license", "version"]
 requires-python = ">=3.6"
-dependencies = ["importlib-metadata>=0.12;python_version<\"3.8\""]
+dependencies = ['importlib-metadata>=0.12;python_version<"3.8"']
 
 [project.readme]
 file = "README.rst"

tests/examples/pyscaffold/pyproject.toml

@@ -23,7 +23,7 @@ classifiers = [
 dynamic = ["license", "version"]
 requires-python = ">=3.6"
 dependencies = [
-    "importlib-metadata; python_version<\"3.8\"",
+    'importlib-metadata; python_version<"3.8"',
     "appdirs>=1.4.4,<2",
     "configupdater>=3.0,<4",
     "setuptools>=46.1.0",
@@ -125,7 +125,9 @@ license-files = ["LICEN[CS]E*", "COPYING*", "NOTICE*", "AUTHORS*"]
 # in order to write a coverage file that can be read by Jenkins.
 # CAUTION: --cov flags may prohibit setting breakpoints while debugging.
 # Comment those flags to avoid this pytest issue.
-addopts = "--cov pyscaffold --cov-config .coveragerc --cov-report term-missing\n--verbose"
+addopts = """
+--cov pyscaffold --cov-config .coveragerc --cov-report term-missing
+--verbose"""
 # In order to use xdist, the developer can add, for example, the following
 # arguments:
 # --dist=load --numprocesses=auto
@@ -160,7 +162,13 @@ formats = "bdist_wheel"
 max_line_length = "88"
 # E203 and W503 have edge cases handled by black
 extend_ignore = "E203, W503"
-exclude = "\nsrc/pyscaffold/contrib\n.tox\nbuild\ndist\n.eggs\ndocs/conf.py"
+exclude = """
+src/pyscaffold/contrib
+.tox
+build
+dist
+.eggs
+docs/conf.py"""
 
 [tool.mypy]
 ignore_missing_imports = true

tests/examples/setuptools_docs/pyproject.toml

@@ -15,7 +15,7 @@ classifiers = [
 dynamic = ["readme", "license", "version"]
 dependencies = [
     "requests",
-    "importlib; python_version == \"2.6\"",
+    'importlib; python_version == "2.6"',
 ]
 
 [project.optional-dependencies]

tests/examples/virtualenv/pyproject.toml

@@ -38,8 +38,8 @@ dependencies = [
     "filelock>=3.0.0,<4",
     "platformdirs>=2,<3",
     "six>=1.9.0,<2", # keep it >=1.9.0 as it may cause problems on LTS platforms
-    "importlib-metadata>=0.12;python_version<\"3.8\"",
-    "importlib-resources>=1.0;python_version<\"3.7\"",
+    'importlib-metadata>=0.12;python_version<"3.8"',
+    'importlib-resources>=1.0;python_version<"3.7"',
     "pathlib2>=2.3.3,<3;python_version < '3.4' and sys.platform != 'win32'",
 ]
 
@@ -99,7 +99,7 @@ testing = [
     "pytest-mock>=2",
     "pytest-randomly>=1",
     "pytest-timeout>=1",
-    "packaging>=20.0;python_version>\"3.4\"",
+    'packaging>=20.0;python_version>"3.4"',
 ]
 
 [project.scripts]
@@ -138,4 +138,6 @@ universal = true
 markers = ["slow"]
 junit_family = "xunit2"
 addopts = "--tb=auto -ra --showlocals --no-success-flaky-report"
-env = "PYTHONWARNINGS=ignore:DEPRECATION::pip._internal.cli.base_command\nPYTHONIOENCODING=utf-8"
+env = """
+PYTHONWARNINGS=ignore:DEPRECATION::pip._internal.cli.base_command
+PYTHONIOENCODING=utf-8"""

tests/examples/zipp/pyproject.toml

@@ -25,9 +25,9 @@ testing = [
     "pytest >= 6",
     "pytest-checkdocs >= 2.4",
     "pytest-flake8",
-    "pytest-black >= 0.3.7; python_implementation != \"PyPy\"", # workaround for jaraco/skeleton#22
+    'pytest-black >= 0.3.7; python_implementation != "PyPy"', # workaround for jaraco/skeleton#22
     "pytest-cov",
-    "pytest-mypy; python_implementation != \"PyPy\"", # workaround for jaraco/skeleton#22
+    'pytest-mypy; python_implementation != "PyPy"', # workaround for jaraco/skeleton#22
     "pytest-enabler >= 1.0.1",
     # local
     "jaraco.itertools",

tests/plugins/test_setuptools_pep621.py

@@ -130,7 +130,7 @@ def test_convert_directives(plugin, parse, convert):
 zip-safe = false # comment
 package-dir = {"" = "src"}
 install-requires = [
-    "importlib-metadata; python_version<\\"3.8\\"",
+    'importlib-metadata; python_version<"3.8"',
     "configupdater>=3,<=4",
 ]