View Issue Details [ Jump to Notes ]

[ Print ]

Project

Category

View Status

Date Submitted

Last Update

0006852

CMake

public

2008-04-19 14:41

2008-04-21 17:51

Reporter

irwin

Assigned To

Priority

normal

Severity

minor

Reproducibility

always

Status

closed

Resolution

fixed

Platform

OS Version

Product Version

CMake-2-6

Target Version

Fixed in Version

Summary

0006852: LIST does not handle empty elements consistently or correctly

Description

The attached CMakeLists.txt file demonstrates a number of issues with the CMake LIST command with either CMake 2.4.8 or 2.6.0 RC-8 if the list contains empty elements. Results for LENGTH, GET, REMOVE_AT, REMOVE_ITEM, SORT,
REVERSE, and INSERT are consistent with the mental model that no indices are
assigned to empty elements of a CMake list, and the result has the empty
elements dropped (which by accident gives the correct result for REMOVE_ITEM
when an empty element is dropped). However, from the above results APPEND
keeps those empty elements in the result, as does FIND, (but FIND cannot
find those empty elements).

I am not aware of any other language that ignores empty elements or drops
them from the results for certain operations so I believe the above results
are symptoms of a language bug that needs to be addressed. I don't know
CMake well enough to give you a patch, but I assume it is a fairly trivial
fix.

The attached CMakeLists.txt also shows that any attempt to INSERT items exactly after the last element of the list fails with an out of range error. The INSERT should do the same thing as an APPEND in this case. Formally, this is a separate wish-list bug, but I am reporting it here since the fix is best done at the same time as the fix for the empty item problems.

Tags

No tags attached.

Attached Files

CMakeLists.txt [^] (2,006 bytes) 2008-04-19 14:41 [Show Content] [Hide Content]

set(list_example "1;;;2;3;4")
message("input list_example = ${list_example}")
list(APPEND list_example "5")
message("appended list_example = ${list_example}")
message("")

list(LENGTH list_example list_example_length)
message("list_example_length = ${list_example_length}")
message("")

list(GET list_example 1 list_example1)
message("element 1 from list_example = ${list_example1}")
message("")

list(GET list_example 5 list_example5)
message("element 5 from list_example = ${list_example5}")
message("")

set(list_example "1;;;2;3;4;5")
message("input list_example = ${list_example}")
list(SORT list_example)
message("sorted list_example = ${list_example}")
message("")

set(list_example "1;;;2;3;4;5")
message("input list_example = ${list_example}")
list(REVERSE list_example)
message("reversed list_example = ${list_example}")
message("")

set(list_example "1;;;2;3;4;5")
message("input list_example = ${list_example}")
list(FIND list_example "1" one_index)
message("list_example after find = ${list_example}")
message("one_index = ${one_index}")
message("")

set(list_example "1;;;2;3;4;5")
message("input list_example = ${list_example}")
list(FIND list_example "" null_index)
message("list_example after find = ${list_example}")
message("null_index = ${null_index}")
message("")

set(list_example "1;;;2;3;4;5")
message("input list_example = ${list_example}")
list(REMOVE_ITEM list_example "1")
message("remove 1 list_example = ${list_example}")
message("")

set(list_example "1;;;2;3;4;5")
message("input list_example = ${list_example}")
list(REMOVE_ITEM list_example "")
message("remove empty list_example = ${list_example}")
message("")

set(list_example "1;;;2;3;4;5")
message("input list_example = ${list_example}")
list(INSERT list_example 4 6 7)
message("insert 4 6 7 list_example = ${list_example}")
message("")

set(list_example "1;;;2;3;4;5")
message("input list_example = ${list_example}")
list(INSERT list_example 5 6 7)
message("insert 5 6 7 list_example = ${list_example}")
message("")

rc8_cmake.out [^] (1,359 bytes) 2008-04-19 14:43

Relationships

Notes
(0011440) irwin (reporter) 2008-04-19 14:45	Attached rc8.cmake.out is cmake output for attached CMakeLists.txt.

(0011464) Bill Hoffman (manager) 2008-04-21 17:51	To avoid breaking backwards compatibility I have created a new policy for this: CMP0007 If you set the policy to NEW, then empty elements are not skipped: cmake_policy(SET CMP0007 NEW) The default will be to warn when empty elements are found in a list given to the list command. $ cvs commit -m "ENH: fix list command with empty elements" cmListCommand.cxx c mPolicies.h cmPolicies.cxx /cvsroot/CMake/CMake/Source/cmListCommand.cxx,v <-- cmListCommand.cxx new revision: 1.20; previous revision: 1.19 /cvsroot/CMake/CMake/Source/cmPolicies.h,v <-- cmPolicies.h new revision: 1.15; previous revision: 1.14 /cvsroot/CMake/CMake/Source/cmPolicies.cxx,v <-- cmPolicies.cxx new revision: 1.30; previous revision: 1.29

Issue History
Date Modified	Username	Field	Change
2008-04-19 14:41	irwin	New Issue
2008-04-19 14:41	irwin	File Added: CMakeLists.txt
2008-04-19 14:43	irwin	File Added: rc8_cmake.out
2008-04-19 14:45	irwin	Note Added: 0011440
2008-04-21 17:51	Bill Hoffman	Status	new => closed
2008-04-21 17:51	Bill Hoffman	Note Added: 0011464
2008-04-21 17:51	Bill Hoffman	Resolution	open => fixed