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Diffstat (limited to 'Doc/whatsnew')
| -rw-r--r-- | Doc/whatsnew/3.7.rst | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/Doc/whatsnew/3.7.rst b/Doc/whatsnew/3.7.rst index 9785d59..992d9ba 100644 --- a/Doc/whatsnew/3.7.rst +++ b/Doc/whatsnew/3.7.rst @@ -70,6 +70,7 @@ Summary -- Release highlights New Features ============ + .. _whatsnew37-pep538: PEP 538: Legacy C Locale Coercion @@ -107,6 +108,7 @@ locale remains active when the core interpreter is initialized. :pep:`538` -- Coercing the legacy C locale to a UTF-8 based locale PEP written and implemented by Nick Coghlan. + .. _whatsnew37-pep553: PEP 553: Built-in breakpoint() @@ -203,6 +205,44 @@ resolution on Linux and Windows. PEP written and implemented by Victor Stinner +.. _whatsnew37-pep565: + +PEP 565: Show DeprecationWarning in ``__main__`` +------------------------------------------------ + +The default handling of :exc:`DeprecationWarning` has been changed such that +these warnings are once more shown by default, but only when the code +triggering them is running directly in the ``__main__`` module. As a result, +developers of single file scripts and those using Python interactively should +once again start seeing deprecation warnings for the APIs they use, but +deprecation warnings triggered by imported application, library and framework +modules will continue to be hidden by default. + +As a result of this change, the standard library now allows developers to choose +between three different deprecation warning behaviours: + +* :exc:`FutureWarning`: always displayed by default, recommended for warnings + intended to be seen by application end users (e.g. for deprecated application + configuration settings). +* :exc:`DeprecationWarning`: displayed by default only in ``__main__`` and when + running tests, recommended for warnings intended to be seen by other Python + developers where a version upgrade may result in changed behaviour or an + error. +* :exc:`PendingDeprecationWarning`: displayed by default only when running + tests, intended for cases where a future version upgrade will change the + warning category to :exc:`DeprecationWarning` or :exc:`FutureWarning`. + +Previously both :exc:`DeprecationWarning` and :exc:`PendingDeprecationWarning` +were only visible when running tests, which meant that developers primarily +writing single file scripts or using Python interactively could be surprised +by breaking changes in the APIs they used. + +.. seealso:: + + :pep:`565` -- Show DeprecationWarning in ``__main__`` + PEP written and implemented by Nick Coghlan + + PEP 540: Add a new UTF-8 mode ----------------------------- |