Asp Forum - File.basename bug?

Reid Thompson

5/11/2009 3:44:00 PM

How often do people get bitten by this?
When operating on a file in the current directory, './' must be
prepended to a filename for File.basename to work...

or is this unexpected behavior?

$ cat bug.rb
DATAFORMAT_VERSION=1

def processInputFile(inputFpath)
puts "inputFpath #{inputFpath}"
dirpath = File.dirname(inputFpath)

outputfile = File.basename(inputFpath)
outputfile.gsub!("pp_",'')
outputfile = dirpath + '/' + 'SDF_' + "#{DATAFORMAT_VERSION}" + '_' + outputfile
puts "outputfile #{outputfile}"
puts "inputFpath #{inputFpath}"

end

processInputFile("pp_a_test_file_name")
rthompso@raker>/home/rthompso
$ ruby bug.rb
inputFpath pp_a_test_file_name
outputfile ./SDF_1_a_test_file_name
inputFpath a_test_file_name
rthompso@raker>/home/rthompso
$ ruby -v
ruby 1.8.7 (2009-04-08 patchlevel 160) [i686-linux]

rthompso@raker>/home/rthompso
$ vi bug.rb
rthompso@raker>/home/rthompso
$ ruby bug.rb
inputFpath /home/rthompso/pp_a_test_file_name
outputfile /home/rthompso/SDF_1_a_test_file_name
inputFpath /home/rthompso/pp_a_test_file_name

6 Answers

lasitha

5/11/2009 6:11:00 PM

On Mon, May 11, 2009 at 9:14 PM, Reid Thompson <reid.thompson@ateb.com> wro=
te:
> How often do people get bitten by this?
> When operating on a file in the current directory, './' must be
> prepended to a filename for File.basename to work...

Hi, i'm either not understanding your issue or not seeing it on my box:

$: cd /tmp; touch by.touch

$: ruby19 -ve "puts File.basename 'by.touch'"
ruby 1.9.1p0 (2009-01-30) [i386-darwin8.11.1]
by.touch

$: ruby -ve "puts File.basename 'by.touch'"
ruby 1.8.7 (2008-08-11 patchlevel 72) [i686-darwin8]
by.touch

> $ cat bug.rb
> DATAFORMAT_VERSION=3D1
>
> def processInputFile(inputFpath)
> =A0 =A0puts "inputFpath #{inputFpath}"
> =A0 =A0dirpath =3D File.dirname(inputFpath)
>
> =A0 =A0outputfile =3D File.basename(inputFpath)
> =A0 =A0outputfile.gsub!("pp_",'')
> =A0 =A0outputfile =3D dirpath + '/' + 'SDF_' + "#{DATAFORMAT_VERSION}" + =
'_' + outputfile
> =A0 =A0puts "outputfile #{outputfile}"
> =A0 =A0puts "inputFpath #{inputFpath}"
>
> end
>
> processInputFile("pp_a_test_file_name")
> rthompso@raker>/home/rthompso
> $ ruby bug.rb
> inputFpath pp_a_test_file_name
> outputfile ./SDF_1_a_test_file_name
> inputFpath a_test_file_name
> rthompso@raker>/home/rthompso
> $ ruby -v
> ruby 1.8.7 (2009-04-08 patchlevel 160) [i686-linux]
>
> rthompso@raker>/home/rthompso
> $ vi bug.rb
> rthompso@raker>/home/rthompso
> $ ruby bug.rb
> inputFpath /home/rthompso/pp_a_test_file_name
> outputfile /home/rthompso/SDF_1_a_test_file_name
> inputFpath /home/rthompso/pp_a_test_file_name

Scanned over the above but couldn't spot what you might be on about :)
Perhaps you could clarify or wittle the example down a bit further?

cheers,
lasitha

Reid Thompson

5/11/2009 6:22:00 PM

On Tue, 2009-05-12 at 03:10 +0900, lasitha wrote:
> On Mon, May 11, 2009 at 9:14 PM, Reid Thompson <reid.thompson@ateb.com> wrote:
> > How often do people get bitten by this?
> > When operating on a file in the current directory, './' must be
> > prepended to a filename for File.basename to work...
>
> Hi, i'm either not understanding your issue or not seeing it on my box:
>
> $: cd /tmp; touch by.touch
>
> $: ruby19 -ve "puts File.basename 'by.touch'"
> ruby 1.9.1p0 (2009-01-30) [i386-darwin8.11.1]
> by.touch
>
> $: ruby -ve "puts File.basename 'by.touch'"
> ruby 1.8.7 (2008-08-11 patchlevel 72) [i686-darwin8]
> by.touch
>
> > $ cat bug.rb
> > DATAFORMAT_VERSION=1
> >
> > def processInputFile(inputFpath)
> > puts "inputFpath #{inputFpath}"
> > dirpath = File.dirname(inputFpath)
> >
> > outputfile = File.basename(inputFpath)
> > outputfile.gsub!("pp_",'')
> > outputfile = dirpath + '/' + 'SDF_' + "#{DATAFORMAT_VERSION}" + '_' + outputfile
> > puts "outputfile #{outputfile}"
> > puts "inputFpath #{inputFpath}"
> >
> > end
> >
> > processInputFile("pp_a_test_file_name")
> > rthompso@raker>/home/rthompso
> > $ ruby bug.rb
> > inputFpath pp_a_test_file_name
> > outputfile ./SDF_1_a_test_file_name
> > inputFpath a_test_file_name
> > rthompso@raker>/home/rthompso
> > $ ruby -v
> > ruby 1.8.7 (2009-04-08 patchlevel 160) [i686-linux]
> >
> > rthompso@raker>/home/rthompso
> > $ vi bug.rb
> > rthompso@raker>/home/rthompso
> > $ ruby bug.rb
> > inputFpath /home/rthompso/pp_a_test_file_name
> > outputfile /home/rthompso/SDF_1_a_test_file_name
> > inputFpath /home/rthompso/pp_a_test_file_name
>
> Scanned over the above but couldn't spot what you might be on about :)
> Perhaps you could clarify or wittle the example down a bit further?
>
> cheers,
> lasitha
>

example 1 -> processInputFile("pp_a_test_file_name")
"pp_a_test_file_name" is a string object
File.basename sets outputfile to the same object as
"pp_a_test_file_name".
as a result the gsub! action on outputfile acts on the
"pp_a_test_file_name" object.

example 2 -> processInputFile("./pp_a_test_file_name")
"./pp_a_test_file_name" is a string object
File.basename sets outputfile to a new object as "pp_a_test_file_name".
as a result the gsub! action on outputfile acts on the new object,
without modifying the original "./pp_a_test_file_name"

Robert Klemme

5/11/2009 6:27:00 PM

On 11.05.2009 20:10, lasitha wrote:
> On Mon, May 11, 2009 at 9:14 PM, Reid Thompson <reid.thompson@ateb.com> wrote:
>> How often do people get bitten by this?
>> When operating on a file in the current directory, './' must be
>> prepended to a filename for File.basename to work...
>
> Hi, i'm either not understanding your issue or not seeing it on my box:
>
> $: cd /tmp; touch by.touch
>
> $: ruby19 -ve "puts File.basename 'by.touch'"
> ruby 1.9.1p0 (2009-01-30) [i386-darwin8.11.1]
> by.touch
>
> $: ruby -ve "puts File.basename 'by.touch'"
> ruby 1.8.7 (2008-08-11 patchlevel 72) [i686-darwin8]
> by.touch
>
>> $ cat bug.rb
>> DATAFORMAT_VERSION=1
>>
>> def processInputFile(inputFpath)
>> puts "inputFpath #{inputFpath}"
>> dirpath = File.dirname(inputFpath)
>>
>> outputfile = File.basename(inputFpath)

This can be combined as

dir, out = File.split input_path

>> outputfile.gsub!("pp_",'')
>> outputfile = dirpath + '/' + 'SDF_' + "#{DATAFORMAT_VERSION}" + '_' + outputfile
>> puts "outputfile #{outputfile}"
>> puts "inputFpath #{inputFpath}"
>>
>> end
>>
>> processInputFile("pp_a_test_file_name")
>> rthompso@raker>/home/rthompso
>> $ ruby bug.rb
>> inputFpath pp_a_test_file_name
>> outputfile ./SDF_1_a_test_file_name
>> inputFpath a_test_file_name

This output cannot come from the code above as "inputFpath" does not
change in the method.

>> rthompso@raker>/home/rthompso
>> $ ruby -v
>> ruby 1.8.7 (2009-04-08 patchlevel 160) [i686-linux]
>>
>> rthompso@raker>/home/rthompso
>> $ vi bug.rb
>> rthompso@raker>/home/rthompso
>> $ ruby bug.rb
>> inputFpath /home/rthompso/pp_a_test_file_name
>> outputfile /home/rthompso/SDF_1_a_test_file_name
>> inputFpath /home/rthompso/pp_a_test_file_name
>
> Scanned over the above but couldn't spot what you might be on about :)
> Perhaps you could clarify or wittle the example down a bit further?

I am assuming that not all tests were done with the same version of the
code and this might have led to confusion. :-)

Kind regards

robert

Robert Klemme

5/11/2009 6:45:00 PM

On 11.05.2009 20:21, Reid Thompson wrote:
> On Tue, 2009-05-12 at 03:10 +0900, lasitha wrote:
>> On Mon, May 11, 2009 at 9:14 PM, Reid Thompson <reid.thompson@ateb.com> wrote:
>>> How often do people get bitten by this?
>>> When operating on a file in the current directory, './' must be
>>> prepended to a filename for File.basename to work...
>> Hi, i'm either not understanding your issue or not seeing it on my box:
>>
>> $: cd /tmp; touch by.touch
>>
>> $: ruby19 -ve "puts File.basename 'by.touch'"
>> ruby 1.9.1p0 (2009-01-30) [i386-darwin8.11.1]
>> by.touch
>>
>> $: ruby -ve "puts File.basename 'by.touch'"
>> ruby 1.8.7 (2008-08-11 patchlevel 72) [i686-darwin8]
>> by.touch
>>
>>> $ cat bug.rb
>>> DATAFORMAT_VERSION=1
>>>
>>> def processInputFile(inputFpath)
>>> puts "inputFpath #{inputFpath}"
>>> dirpath = File.dirname(inputFpath)
>>>
>>> outputfile = File.basename(inputFpath)
>>> outputfile.gsub!("pp_",'')
>>> outputfile = dirpath + '/' + 'SDF_' + "#{DATAFORMAT_VERSION}" + '_' + outputfile
>>> puts "outputfile #{outputfile}"
>>> puts "inputFpath #{inputFpath}"
>>>
>>> end
>>>
>>> processInputFile("pp_a_test_file_name")
>>> rthompso@raker>/home/rthompso
>>> $ ruby bug.rb
>>> inputFpath pp_a_test_file_name
>>> outputfile ./SDF_1_a_test_file_name
>>> inputFpath a_test_file_name
>>> rthompso@raker>/home/rthompso
>>> $ ruby -v
>>> ruby 1.8.7 (2009-04-08 patchlevel 160) [i686-linux]
>>>
>>> rthompso@raker>/home/rthompso
>>> $ vi bug.rb
>>> rthompso@raker>/home/rthompso
>>> $ ruby bug.rb
>>> inputFpath /home/rthompso/pp_a_test_file_name
>>> outputfile /home/rthompso/SDF_1_a_test_file_name
>>> inputFpath /home/rthompso/pp_a_test_file_name
>> Scanned over the above but couldn't spot what you might be on about :)
>> Perhaps you could clarify or wittle the example down a bit further?
>>
>> cheers,
>> lasitha
>>
>
> example 1 -> processInputFile("pp_a_test_file_name")
> "pp_a_test_file_name" is a string object
> File.basename sets outputfile to the same object as
> "pp_a_test_file_name".
> as a result the gsub! action on outputfile acts on the
> "pp_a_test_file_name" object.
>
> example 2 -> processInputFile("./pp_a_test_file_name")
> "./pp_a_test_file_name" is a string object
> File.basename sets outputfile to a new object as "pp_a_test_file_name".
> as a result the gsub! action on outputfile acts on the new object,
> without modifying the original "./pp_a_test_file_name"

Heureka! It's an aliasing problem which is not there in 1.9:

$ irb19
irb(main):001:0> s = 'foo.txt'
=> "foo.txt"
irb(main):002:0> x = File.basename s
=> "foo.txt"
irb(main):003:0> s.equal? x
=> false
irb(main):004:0> s.object_id
=> 134667930
irb(main):005:0> x.object_id
=> 134637100
irb(main):006:0>

$ irb
irb(main):001:0> s = 'foo'
=> "foo"
irb(main):002:0> x = File.basename s
=> "foo"
irb(main):003:0> s.equal? x
=> true
irb(main):004:0> s.object_id
=> 1073538940
irb(main):005:0> x.object_id
=> 1073538940
irb(main):006:0>

Whether you consider this actually a bug of File.basename - I don't
know. It is at least a documentation bug because the docs do not
mention that fact.

Kind regards

robert

--
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestprac...

Reid Thompson

5/11/2009 7:34:00 PM

On Tue, 2009-05-12 at 03:30 +0900, Robert Klemme wrote:
> On 11.05.2009 20:10, lasitha wrote:
> > On Mon, May 11, 2009 at 9:14 PM, Reid Thompson <reid.thompson@ateb.com> wrote:
> >> How often do people get bitten by this?
> >> When operating on a file in the current directory, './' must be
> >> prepended to a filename for File.basename to work...
> >
> > Hi, i'm either not understanding your issue or not seeing it on my box:
> >
> > $: cd /tmp; touch by.touch
> >
> > $: ruby19 -ve "puts File.basename 'by.touch'"
> > ruby 1.9.1p0 (2009-01-30) [i386-darwin8.11.1]
> > by.touch
> >
> > $: ruby -ve "puts File.basename 'by.touch'"
> > ruby 1.8.7 (2008-08-11 patchlevel 72) [i686-darwin8]
> > by.touch
> >
> >> $ cat bug.rb
> >> DATAFORMAT_VERSION=1
> >>
> >> def processInputFile(inputFpath)
> >> puts "inputFpath #{inputFpath}"
> >> dirpath = File.dirname(inputFpath)
> >>
> >> outputfile = File.basename(inputFpath)
>
> This can be combined as
>
> dir, out = File.split input_path
>
> >> outputfile.gsub!("pp_",'')
> >> outputfile = dirpath + '/' + 'SDF_' + "#{DATAFORMAT_VERSION}" + '_' + outputfile
> >> puts "outputfile #{outputfile}"
> >> puts "inputFpath #{inputFpath}"
> >>
> >> end
> >>
> >> processInputFile("pp_a_test_file_name")
> >> rthompso@raker>/home/rthompso
> >> $ ruby bug.rb
> >> inputFpath pp_a_test_file_name
> >> outputfile ./SDF_1_a_test_file_name
> >> inputFpath a_test_file_name
>
> This output cannot come from the code above as "inputFpath" does not
> change in the method.
Not sure what you mean -- this output did come from the above code.
inputFpath is modified by the gsub! call on outputfile

rthompso@raker>/home/rthompso
$ irb
irb(main):001:0> DATAFORMAT_VERSION=1
=> 1
irb(main):002:0>
irb(main):003:0* def processInputFile(inputFpath)
irb(main):004:1> puts "inputFpath #{inputFpath}"
irb(main):005:1> dirpath = File.dirname(inputFpath)
irb(main):006:1>
irb(main):007:1* outputfile = File.basename(inputFpath)
irb(main):008:1> outputfile.gsub!("pp_",'')
irb(main):009:1> outputfile = dirpath + '/' + 'SDF_' + "#{DATAFORMAT_VERSION}" + '_' + outputfile
irb(main):010:1> puts "outputfile #{outputfile}"
irb(main):011:1> puts "inputFpath #{inputFpath}"
irb(main):012:1>
irb(main):013:1* end
=> nil
irb(main):014:0>
irb(main):015:0* processInputFile("pp_a_test_file_name")
inputFpath pp_a_test_file_name
outputfile ./SDF_1_a_test_file_name
inputFpath a_test_file_name
=> nil

>
> >> rthompso@raker>/home/rthompso
> >> $ ruby -v
> >> ruby 1.8.7 (2009-04-08 patchlevel 160) [i686-linux]
> >>
> >> rthompso@raker>/home/rthompso
> >> $ vi bug.rb
> >> rthompso@raker>/home/rthompso
> >> $ ruby bug.rb
> >> inputFpath /home/rthompso/pp_a_test_file_name
> >> outputfile /home/rthompso/SDF_1_a_test_file_name
> >> inputFpath /home/rthompso/pp_a_test_file_name
> >
> > Scanned over the above but couldn't spot what you might be on about :)
> > Perhaps you could clarify or wittle the example down a bit further?
>
> I am assuming that not all tests were done with the same version of the
> code and this might have led to confusion. :-)
>
> Kind regards
>
> robert
>

Robert Klemme

5/11/2009 8:30:00 PM

On 11.05.2009 21:33, Reid Thompson wrote:
> On Tue, 2009-05-12 at 03:30 +0900, Robert Klemme wrote:

>> This output cannot come from the code above as "inputFpath" does not
>> change in the method.
> Not sure what you mean -- this output did come from the above code.
> inputFpath is modified by the gsub! call on outputfile

You are right. It's an aliasing problem not present in 1.9.1 which I am
using. See my other posting.

Kind regards

robert

comp.lang.ruby

File.basename bug?

Reid Thompson

lasitha

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Robert Klemme

Robert Klemme

Reid Thompson

Robert Klemme

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