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IDProjectCategoryView StatusDate SubmittedLast Update
00001551003.1(2008)/Issue 7Shell and Utilitiespublic2009-09-22 11:242013-04-16 13:06
Reportergeoffclare Assigned Toajosey  
PrioritynormalSeverityObjectionTypeError
Status ClosedResolutionAccepted 
NameGeoff Clare
OrganizationThe Open Group
User Reference
Section2.14 set
Page Number2359
Line Number74590
Interp StatusApproved
Final Accepted Text0000155:0000290
Summary0000155: set -u should require an error when $1 etc. are unset
DescriptionA discussion on the austin-group-l mailing list in May 2009
identified a problem with the description of set -u. Since it
uses the word "variable" instead of "parameter", the shell is not
required to report an error if the positional parameters $1, $2,
etc. are used when unset. This does not match existing practice.

The question then arose of how to correct the problem, particularly
the detail of whether set -u should apply to $@ and $*. It was
felt that it should not apply to these, even though some shells do
currently report an error for them, since it is normal and common
for $@ and $* to be used in shell scripts regardless of whether they
were passed any arguments.
Desired ActionChange:

    "The shell shall write a message to standard error when it tries
    to expand a variable that is not set and immediately exit."

to:

    "The shell shall write a message to standard error and immediately
    exit when it tries to expand an unset parameter other than the '@'
    and '*' special parameters."

Add to RATIONALE for set after line 74714:

    "Historically some shells applied the -u option to all parameters
    including $@ and $*. The standard developers felt that this was
    a misfeature since it is normal and common for $@ and $* to be
    used in shell scripts regardless of whether they were passed any
    arguments. Treating these uses as an error when no arguments are
    passed reduces the value of -u for its intended purpose of
    finding spelling mistakes in variable names and uses of unset
    positional parameters."
Tagstc1-2008

Relationships

related to 0000457 Closedajosey omitted word in parameter expansions 
related to 0000559 Closedajosey arithmetic expansion should honor 'set -u' 
related to 0000280 Closedajosey description is not clear enought on what happens if the shell immediately exits 

Activities

msbrown

2009-09-24 15:57

manager   bugnote:0000240

"The standard states
"The shell shall write a message to standard error when it tries
    to expand a variable that is not set and immediately exit."

and conforming implementations must conform to this. However, concerns have been raised about this which are being referred to the sponsor."

ajosey

2009-11-07 07:27

manager   bugnote:0000290

Last edited: 2009-11-07 07:28

 Interpretation response
------------------------
The standard states "The shell shall write a message to standard error when it tries to expand a variable that is not set and immediately exit." and conforming implementations must conform to this. However, concerns have been raised about this which are being referred to the sponsor."

Rationale:
-------------
None.

Notes to the Editor (not part of this interpretation):
-------------------------------------------------------
Make the change suggested by the submitter

Issue History

Date Modified Username Field Change
2009-09-22 11:24 geoffclare New Issue
2009-09-22 11:24 geoffclare Status New => Under Review
2009-09-22 11:24 geoffclare Assigned To => ajosey
2009-09-22 11:24 geoffclare Name => Geoff Clare
2009-09-22 11:24 geoffclare Organization => The Open Group
2009-09-22 11:24 geoffclare Section => 2.14 set
2009-09-22 11:24 geoffclare Page Number => 2359
2009-09-22 11:24 geoffclare Line Number => 74590
2009-09-22 11:24 geoffclare Interp Status => ---
2009-09-24 15:57 msbrown Interp Status --- => Pending
2009-09-24 15:57 msbrown Note Added: 0000240
2009-09-24 15:57 msbrown Status Under Review => Interpretation Required
2009-09-24 15:57 msbrown Resolution Open => Accepted
2009-11-07 07:27 ajosey Note Added: 0000290
2009-11-07 07:28 ajosey Interp Status Pending => Proposed
2009-11-07 07:28 ajosey Final Accepted Text => 0000155:0000290
2009-11-07 07:28 ajosey Note Edited: 0000290
2009-11-07 07:28 ajosey Note Edited: 0000290
2009-12-07 16:55 ajosey Interp Status Proposed => Approved
2010-09-21 11:19 geoffclare Tag Attached: tc1-2008
2011-06-03 18:24 eblake Relationship added related to 0000457
2012-04-26 17:18 eblake Relationship added related to 0000559
2012-05-11 08:08 geoffclare Relationship added related to 0000280
2013-04-16 13:06 ajosey Status Interpretation Required => Closed