Bizarr problem with rake

I hope that someone here can identify what is going on as I am completely frustrated at the moment.

I am writing a custom rake task for rcov. The intent is top produce three variants of a test, each using slightly different options. This is the basic code:


  # Use single quotes here so that regexp argument is not munged.   R_RCOV_EXCLUDE_DIR = 'lib\/ruby,lib64\/ruby'

  R_RCOV_OUTPUT_DIR = 'test_coverage'

  R_RCOV_AGGREG_OPTS = "--aggregate #{R_RCOV_AGGREG_FILE} " +                         "--text-summary --no-html "

  R_RCOV_BASIC_OPTS = [ " --rails ", " --exclude #{R_RCOV_EXCLUDE_DIR} " ]

  R_RCOV_FINAL_OPTS = " --aggregate #{R_RCOV_AGGREG_FILE} "

  R_RCOV_BROWSER = 'firefox'

  # make the output directory an array.   r_rcov_dir = R_RCOV_OUTPUT_DIR.scan(/\w+/)

  [ 'single', 'aggregate', 'final' ].each do |reptype|

    # Set the rcov options variables according to report type     r_rcov_opta = nil if reptype == 'single'     r_rcov_opta = R_RCOV_AGGREG_OPTS if reptype == 'aggregate'     r_rcov_opta = R_RCOV_FINAL_OPTS if reptype == 'final'

    # builds task int_testunit_X"int_testunit_#{reptype}") do |t|       t.test_files = FileList['test/**/test*.rb']       t.libs << "test"       t.output_dir = r_rcov_dir       t.rcov_opts = R_RCOV_BASIC_OPTS       t.rcov_opts << r_rcov_opta       puts "testunit #{reptype} opts: #{R_RCOV_BASIC_OPTS} size " +             "#{R_RCOV_BASIC_OPTS.size}"       puts " "       puts "testunit #{reptype} opta: #{r_rcov_opta}"       puts " "       puts "testunit #{reptype} options: #{t.rcov_opts}"       puts " "       t.verbose = true     end   end

The problem is this. Somewhere the constant value R_RCOV_BASIC_OPTS is being changed. A rake run using puts and displaying R_RCOV_BASIC_OPTS.size gives this output:

testunit single opts: --rails --exclude lib\/ruby,lib64\/ruby size 5

testunit single opta:

testunit single options: --rails --exclude lib\/ruby,lib64\/ruby

testunit aggregate opts: --rails --exclude lib\/ruby,lib64\/ruby --aggregate --text-summary --no-html --aggregate --text-summary --no-html --aggregate --text-summary --no-html size 8

testunit aggregate opta: --aggregate --text-summary --no-html

testunit aggregate options: --rails --exclude lib\/ruby,lib64\/ruby --aggregate --text-summary --no-html --aggregate --text-summary --no-html --aggregate --text-summary --no-html

testunit final opts: --rails --exclude lib\/ruby,lib64\/ruby --aggregate --text-summary --no-html --aggregate --text-summary --no-html --aggregate --text-summary --no-html --aggregate --aggregate --aggregate size 11

testunit final opta: --aggregate

testunit final options: --rails --exclude lib\/ruby,lib64\/ruby --aggregate --text-summary --no-html --aggregate --text-summary --no-html --aggregate --text-summary --no-html --aggregate --aggregate --aggregate

Checking my rake task lists only these places where R-RCOV_BASIC_OPTS is referenced:

  22 R_RCOV_BASIC_OPTS = [ " --rails ", " --exclude #{R_RCOV_EXCLUDE_DIR} " ]   57 t.rcov_opts = R_RCOV_BASIC_OPTS   68 t.rcov_opts = R_RCOV_BASIC_OPTS   77 t.rcov_opts = R_RCOV_BASIC_OPTS   79 puts "testunit #{reptype} opts: #{R_RCOV_BASIC_OPTS} size " +   80 "#{R_RCOV_BASIC_OPTS.size}"

How is constant getting its value changed?