[bugfix] solve crash when using `inspect()` on the "pyparsing" package #2294

olivierphi · 2022-05-25T09:59:53Z

Type of changes

Bug fix - fixes IndexError: list index out of range when using inspect(pyparsing, all=True) #2284
New feature
Documentation / docstrings
Tests
Other

⚠️ This PR introduces a (minor) breaking change, in order to fix a (minor) issued described with the screenshots below. 👇
But we can of course choose to keep the existing behaviour as-is instead 🙂

Checklist

I've run the latest black with default args on new code.
I've updated CHANGELOG.md and CONTRIBUTORS.md where appropriate. (N/A)
I've added tests for new code.
I accept that @willmcgugan may be pedantic in the code review.

Description

As reported there, running this command was making Rich crash:

python3 -c "import pyparsing; from rich import inspect; inspect(pyparsing, methods=True)"

It took me a while to understand what was going wrong, as the code from which the exception pops is in Text.divide(offsets) which is quite a complex part 🤯
But in the end I identified the culprits 🥷 : special ASCII characters! (in docstrings)

We were removing them from the content of the textual content of the Text class, but when caching the length of this content we were using the length of the non-sanitised text - which causes issues in some cases, as the text we're splitting into several lines doesn't actually have the length we think it has.

Should we make control characters contained in docstrings visible in the inspection?

I first solved the bug by just making sure the cached length of the text is the one of the sanitised version of it, but then I noticed that the result was looking a bit odd with docstrings that contains such special characters, such as the WordStart class of this pyparsing package.

When dumped with inspect we were ending up with "To emulate the ```` behavior of regular expressions", with 4 backticks in a row without content:
That's why I opted for another strategy: replacing these control codes with their "readable" equivalents, so \b is displayed as "\b":

However, although it's rather unlikely I appreciate that doing such a change in Rich's behaviour could break people's code if they were using some parsing over the result of rich.inspect for example.
It depends I guess on whether or not we consider the stripping of control codes in docstrings, when inspecting code, as a feature of a bug? 🤔
If it's feature we may rather choose to keep the existing behaviour for the moment, and potentially change it later on with a major version bump, or an opt-in flag somewhere in Rich? 🙂

olivierphi · 2022-05-25T10:01:28Z

pyproject.toml

@@ -61,3 +61,6 @@ enable_error_code = ["ignore-without-code", "redundant-expr", "truthy-bool"]
 [[tool.mypy.overrides]]
 module = ["pygments.*", "IPython.*", "commonmark.*", "ipywidgets.*"]
 ignore_missing_imports = true
+
+[tool.pytest.ini_options]
+testpaths = ["tests"]


while working on this I noticed that creating a Python script with a name starting ending with test_ anywhere in the project's repo was collected by Pytest: I think we'd better tell Pytest to stick with the contents of our tests/ folder - which should also make the tests collection faster as a side effect

olivierphi · 2022-05-25T10:02:52Z

rich/_inspect.py

@@ -19,12 +19,6 @@ def _first_paragraph(doc: str) -> str:
    return paragraph


-def _reformat_doc(doc: str) -> str:
-    """Reformat docstring."""
-    doc = cleandoc(doc).strip()


I noticed that we were ending up calling cleandoc twice on our extracted docstrings - to remedy this I inlined this operation in a single _get_formatted_doc method, later on this same module

olivierphi · 2022-05-25T10:03:57Z

rich/_inspect.py

            if _doc is not None:
-                if not self.help:


The process of calling cleandoc() on the doctring's content and getting only its first paragraph if self.help is not True is now factorised in a single method, rather than done twice in this class

rich/control.py

olivierphi · 2022-05-25T10:07:50Z

rich/text.py

        self.style = style
        self.justify: Optional["JustifyMethod"] = justify
        self.overflow: Optional["OverflowMethod"] = overflow
        self.no_wrap = no_wrap
        self.end = end
        self.tab_size = tab_size
        self._spans: List[Span] = spans or []
-        self._length: int = len(text)
+        self._length: int = len(sanitized_text)


that's the bugfix itself! 🙂 i.e. we should use the length of the sanitised text, rather than the one of the text we received as an argument

olivierphi · 2022-05-25T10:08:01Z

rich/text.py

            old_length = self._length
-            self._length = len(new_text)
+            self._length = len(sanitized_text)


same bug here 🙂

olivierphi · 2022-05-25T10:08:13Z

rich/text.py

                offset = len(self)
-                text_length = len(text)
+                text_length = len(sanitized_text)


...and here

olivierphi · 2022-05-25T10:09:44Z

tests/test_inspect.py

+        expected_replacement
+    )
+
+    assert render(Something, methods=True) == expected


to make sure that we don't have regressions on this bugfix, before trying to solve it I started by writing a test that reproduce the issue : this test was crashing before the fix, and passes now 🎈

willmcgugan

Great. Just a few pendantic requests, and we should be good to merge.

willmcgugan · 2022-05-27T12:23:58Z

rich/control.py


+_CONTROL_MAKE_READABLE_TRANSLATE: Final = {


Can we call this CONTROL_ESCAPE

willmcgugan · 2022-05-27T12:24:50Z

rich/control.py

@@ -182,6 +198,22 @@ def strip_control_codes(
    return text.translate(_translate_table)


+def make_control_codes_readable(


I'd prefer escape_control_code. Would you mind changing the terminology from "make readable" elsewhere?

willmcgugan · 2022-05-27T12:26:36Z

rich/_inspect.py

@@ -220,3 +210,12 @@ def safe_getattr(attr_name: str) -> Tuple[Any, Any]:
                f"[b cyan]{not_shown_count}[/][i] attribute(s) not shown.[/i] "
                f"Run [b][magenta]inspect[/]([not b]inspect[/])[/b] for options."
            )
+
+    def _get_formatted_doc(self, object_: Any) -> Optional[str]:


Would you mind adding a docstring.

…eadable version in docstrings With this we allow the following: - Such characters will be displayed in the data returned by "rich.inspect" - We fix the crash that can happen in some circumstances in the `Text.divide()` method when some docstrings have such special characters

…eadable version With this we allow the following: - Such characters will be displayed in the data returned by "rich.inspect" when they are used in docstrings - We fix the crash that can happen in some circumstances in the `Text.divide()` method when some docstrings have such special characters

…t with their escaped version

olivierphi · 2022-05-27T13:58:24Z

@willmcgugan "escape control codes" is a better terminology indeed! 🙂
Hopefully this commit addresses your comments: 25d0c0e

codecov-commenter · 2022-05-27T13:59:32Z

Codecov Report

Merging #2294 (25d0c0e) into master (14d47c9) will decrease coverage by 0.12%.
The diff coverage is 95.42%.

@@            Coverage Diff             @@
##           master    #2294      +/-   ##
==========================================
- Coverage   98.88%   98.76%   -0.13%     
==========================================
  Files          73       73              
  Lines        7629     7684      +55     
==========================================
+ Hits         7544     7589      +45     
- Misses         85       95      +10

Flag	Coverage Δ
unittests	`98.76% <95.42%> (-0.13%)`	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
rich/_export_format.py	`100.00% <ø> (ø)`
rich/live.py	`97.90% <40.00%> (-2.10%)`	⬇️
rich/console.py	`98.29% <96.03%> (-0.49%)`	⬇️
rich/_inspect.py	`100.00% <100.00%> (ø)`
rich/control.py	`100.00% <100.00%> (ø)`
rich/syntax.py	`99.30% <100.00%> (+0.02%)`	⬆️
rich/terminal_theme.py	`100.00% <100.00%> (ø)`
rich/text.py	`100.00% <100.00%> (ø)`
rich/traceback.py	`98.68% <0.00%> (-0.88%)`	⬇️

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 5ccf4ed...25d0c0e. Read the comment docs.

willmcgugan · 2022-05-27T14:15:16Z

👍

olivierphi commented May 25, 2022

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olivierphi force-pushed the bugfix-inspect-with-pyparsing branch from 4b1893a to 49e2b1d Compare May 25, 2022 10:32

olivierphi marked this pull request as ready for review May 25, 2022 10:45

olivierphi force-pushed the bugfix-inspect-with-pyparsing branch 2 times, most recently from 2320989 to 74d7807 Compare May 27, 2022 08:24

olivierphi mentioned this pull request May 27, 2022

IndexError: list index out of range when using inspect(pyparsing, all=True) #2284

Closed

willmcgugan requested changes May 27, 2022

View reviewed changes

Olivier Philippon added 3 commits May 27, 2022 14:56

[inspect] Address PR feedback on ASCII special characters' replacemen…

25d0c0e

…t with their escaped version

olivierphi force-pushed the bugfix-inspect-with-pyparsing branch from ce0b2ff to 25d0c0e Compare May 27, 2022 13:57

olivierphi requested a review from willmcgugan May 27, 2022 13:58

willmcgugan approved these changes May 27, 2022

View reviewed changes

willmcgugan merged commit c187270 into master May 27, 2022

willmcgugan deleted the bugfix-inspect-with-pyparsing branch May 27, 2022 14:15

iloveitaly mentioned this pull request Jul 23, 2022

Bump rich from 12.3.0 to 12.5.1 iloveitaly/crypto-index-fund-bot#135

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renovate bot mentioned this pull request Sep 29, 2022

Update all dependencies DiamondLightSource/python-murfey#65

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[bugfix] solve crash when using `inspect()` on the "pyparsing" package #2294

[bugfix] solve crash when using `inspect()` on the "pyparsing" package #2294

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willmcgugan commented May 27, 2022

		@@ -182,6 +198,22 @@ def strip_control_codes(
		return text.translate(_translate_table)


		def make_control_codes_readable(


		_CONTROL_MAKE_READABLE_TRANSLATE: Final = {

[bugfix] solve crash when using inspect() on the "pyparsing" package #2294

[bugfix] solve crash when using inspect() on the "pyparsing" package #2294

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olivierphi commented May 25, 2022 • edited Loading

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Description

Should we make control characters contained in docstrings visible in the inspection?

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olivierphi commented May 27, 2022

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willmcgugan commented May 27, 2022

[bugfix] solve crash when using `inspect()` on the "pyparsing" package #2294

[bugfix] solve crash when using `inspect()` on the "pyparsing" package #2294

olivierphi commented May 25, 2022 •

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