Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Document 'from None' in raise statement doc. #61390

Closed
terryjreedy opened this issue Feb 12, 2013 · 20 comments
Closed

Document 'from None' in raise statement doc. #61390

terryjreedy opened this issue Feb 12, 2013 · 20 comments
Assignees
@terryjreedy
Labels
3.7 (EOL) end of life docs Documentation in the Doc dir easy type-feature A feature request or enhancement

Comments

@terryjreedy
Copy link
Member

BPO 17188
Nosy @terryjreedy, @ncoghlan, @rbtcollins, @benjaminp, @ezio-melotti, @berkerpeksag, @serhiy-storchaka, @Mariatta, @csabella
PRs
  • bpo-17188: DOC: Document 'from None' in raise statement #1671
  • bpo-17188: DOC: Document 'from None' in raise statement #1671
  • [3.6] bpo-17188: DOC: Document 'from None' in raise statement (GH-1671) #1867
  • bpo-17188: add missing periods at the end of sentences #1875
  • [3.6] bpo-17188: add missing periods at the end of sentences (GH-1875) #1876
    		•
    Files
  • patch17188.patch
  • issue17188.patch
  • issue17188_1.patch
  • issue17188_3.4.patch
  • issue17188_3.4.patch
  • issue17188_by_thomir.patch
    		•

    Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.

    Show more details

    GitHub fields:

    assignee = 'https://github.com/terryjreedy'
closed_at = <Date 2017-05-30.20:31:02.679>
created_at = <Date 2013-02-12.01:19:59.419>
labels = ['easy', 'type-feature', '3.7', 'docs']
title = "Document 'from None' in raise statement doc."
updated_at = <Date 2017-05-30.22:38:56.033>
user = 'https://github.com/terryjreedy'

    bugs.python.org fields:

    activity = <Date 2017-05-30.22:38:56.033>
actor = 'Mariatta'
assignee = 'terry.reedy'
closed = True
closed_date = <Date 2017-05-30.20:31:02.679>
closer = 'Mariatta'
components = ['Documentation']
creation = <Date 2013-02-12.01:19:59.419>
creator = 'terry.reedy'
dependencies = []
files = ['29199', '34434', '34527', '44607', '44618', '44967']
hgrepos = []
issue_num = 17188
keywords = ['patch', 'easy']
message_count = 20.0
messages = ['181939', '182213', '182799', '182815', '213640', '214126', '214178', '276132', '276133', '276170', '278110', '293454', '294011', '294013', '294780', '294781', '294786', '294792', '294795', '294796']
nosy_count = 14.0
nosy_names = ['terry.reedy', 'ncoghlan', 'rbcollins', 'benjamin.peterson', 'ezio.melotti', 'Arfrever', 'docs@python', 'berker.peksag', 'serhiy.storchaka', 'me@dennis.is', 'thomir', 'nitika', 'Mariatta', 'cheryl.sabella']
pr_nums = ['1671', '1671', '1867', '1875', '1876']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue17188'
versions = ['Python 3.6', 'Python 3.7']
    @terryjreedy
    Copy link
    Member Author

    Language manual, section 7.8. The raise statement has no mention of the 'from None' option. Indeed it says "if given, the second expression must be another exception class or instance", which would exclude None.

    Library manual, Ch 5. Built-in Exceptions, says
    '''
    When raising a new exception (rather than using a bare raise to re-raise the exception currently being handled), the implicit exception context can be supplemented with an explicit cause by using from with raise:

    raise new_exc from original_exc

    The expression following from must be an exception or None. It will be set as __cause__ on the raised exception. Setting __cause__ also implicitly sets the __suppress_context__ attribute to True, so that using raise new_exc from None effectively replaces the old exception with the new one for display purposes (e.g. converting KeyError to AttributeError, while leaving the old exception available in __context__ for introspection when debugging.
    '''
    I am not sure how much should be copied over, but None should be at least mentioned and perhaps there should be a cross-reference.

    I am also not sure how much applies to 3.2, but there is no version-added or -changed note with the above.

    @terryjreedy terryjreedy added the docs Documentation in the Doc dir label Feb 12, 2013
    @ezio-melotti ezio-melotti added easy type-feature A feature request or enhancement labels Feb 15, 2013
    @ncoghlan
    Copy link
    Contributor

    As Terry notes, the various pieces of "from None" documentation should also have a nearby directive like:

    .. versionchanged: 3.3

    :const:`None` permitted as ``Y`` in ``raise X from Y``

    .. versionadded: 3.3

    The __suppress_context__ attribute to suppress automatic display of the exception context

    @medennisis
    Copy link
    Mannequin

    medennisis mannequin commented Feb 23, 2013

    We have added the from None to the documentation with a explanation and some example code.

    @akheron
    Copy link
    Member

    akheron commented Feb 23, 2013

    The patch should add something to the "The from clause is used for exception..." paragraph, to state that None is also allowed.

    It also adds things in a confusing order. I think the new example should go below other examples, and the changedversion and addedversion directives should be the last thing in the section.

    @nitika
    Copy link
    Mannequin

    nitika mannequin commented Mar 15, 2014

    Hi,
    As suggested by Petri,I have made some changes.
    Please review the attached patch.Any comments and feedback are welcome.

    @nitika
    Copy link
    Mannequin

    nitika mannequin commented Mar 19, 2014

    Patch with some corrections.
    Please review the patch attached.

    @akheron
    Copy link
    Member

    akheron commented Mar 20, 2014

    The patch doesn't apply cleanly on 3.4 or default.

    @thomir
    Copy link
    Mannequin

    thomir mannequin commented Sep 12, 2016

    I have attached a patch for 3.4, based on the patch submitted by Nitika Agarwal. The main difference is that I think it's better to be explicit and show a separate example of raise X from None.

    I will submit a patch for later versions as well.

    @thomir
    Copy link
    Mannequin

    thomir mannequin commented Sep 12, 2016

    OK, it seems that patch applies cleanly to 3.5 and 3.6.

    @thomir
    Copy link
    Mannequin

    thomir mannequin commented Sep 13, 2016

    Re-uploaded the patch without the typo.

    @Mariatta
    Copy link
    Member

    Mariatta commented Oct 5, 2016

    reuploaded thomir's patch issue17188_3.4.patch as is.
    I take no credit for this.

    @csabella
    Copy link
    Contributor

    Would any of the original authors be able to prepare a PR for this? Thanks.

    @terryjreedy
    Copy link
    Member Author

    New changeset 763557e by terryjreedy (csabella) in branch 'master':
    bpo-17188: DOC: Document 'from None' in raise statement (bpo-1671)
    763557e

    @terryjreedy
    Copy link
    Member Author

    The double listing seems to be a glitch.

    Either someone else does backport or online doc change waits until I can do it.

    @terryjreedy terryjreedy added the 3.7 (EOL) end of life label May 20, 2017
    @Mariatta
    Copy link
    Member

    New changeset 00b381b by Mariatta (csabella) in branch '3.6':
    bpo-17188: DOC: Document 'from None' in raise statement (GH-1671) (GH-1867)
    00b381b

    @Mariatta
    Copy link
    Member

    Patch has been applied to 3.7 and 3.6.
    Thanks everyone :)

    @serhiy-storchaka
    Copy link
    Member

    Seems periods at the ends of sentences are missed.

    @Mariatta
    Copy link
    Member

    New changeset 9efad1e by Mariatta in branch 'master':
    bpo-17188: add missing periods at the end of sentences (GH-1875)
    9efad1e

    @Mariatta
    Copy link
    Member

    New changeset 60b257b by Mariatta in branch '3.6':
    bpo-17188: add missing periods at the end of sentences (GH-1875) (GH-1876)
    60b257b

    @Mariatta
    Copy link
    Member

    Thanks Serhiy.
    I added the missing periods.

    @ezio-melotti ezio-melotti transferred this issue from another repository Apr 10, 2022
    Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
    Assignees

    @terryjreedy terryjreedy

    Labels
    3.7 (EOL) end of life docs Documentation in the Doc dir easy type-feature A feature request or enhancement
    Projects
    None yet
    Milestone
    No milestone
    Development

    No branches or pull requests
    7 participants
    @akheron @ncoghlan @serhiy-storchaka @Mariatta @terryjreedy @csabella @ezio-melotti