Alias chaining does not properly restore old methods #9251
Description
In test_cgi_escape.rb there's a section that attempts to undefine the extension methods to force a test of the pure-Ruby versions. The logic looks like this:
class CGIEscapePureRubyTest < Test::Unit::TestCase
def setup
CGI::EscapeExt.module_eval do
alias _escapeHTML escapeHTML
remove_method :escapeHTML
alias _unescapeHTML unescapeHTML
remove_method :unescapeHTML
end if defined?(CGI::EscapeExt) and CGI::EscapeExt.method_defined?(:escapeHTML)
end
def teardown
CGI::EscapeExt.module_eval do
alias escapeHTML _escapeHTML
remove_method :_escapeHTML
alias unescapeHTML _unescapeHTML
remove_method :_unescapeHTML
end if defined?(CGI::EscapeExt) and CGI::EscapeExt.method_defined?(:_escapeHTML)
end
include CGIEscapeTest::UnescapeHTMLTests
...
Unfortunately there appears to be two problems in JRuby with aliasing and re-aliasing the original method:
- The alias should not continue to re-wrap the old alias. Instead, it should use the original alias's contents as its payload.
- The re-aliasing of the original method does not appear to restore either the name or the class to use for super, leading to one of two errors:
Original name fails to be superable after aliasing:
CGIEscapeTest#test_cgi_escapeHTML:IBM037:
NoMethodError: super: no superclass method 'escapeHTML' for class CGI
org/jruby/ext/cgi/escape/CGIEscape.java:402:in 'escapeHTML'
/Users/headius/work/jruby/test/mri/cgi/test_cgi_escape.rb:208:in 'block in CGIEscapeTest'
Stack overflow due to superclass search not progressing (e.g. alias causes a lower class to be the current class, so super just keeps going back to the same class):
org.jruby.dist/org.jruby.runtime.Helpers.invokeSuper(Helpers.java:955)
org.jruby.dist/org.jruby.ext.cgi.escape.CGIEscape.cgiesc_unescape_html(CGIEscape.java:421)
org.jruby.dist/org.jruby.ext.cgi.escape.CGIEscape$INVOKER$s$1$0$cgiesc_unescape_html.call(CGIEscape$INVOKER$s$1$0$cgiesc_unescape_html.gen)
org.jruby.dist/org.jruby.internal.runtime.methods.JavaMethod$JavaMethodOneOrN.call(JavaMethod.java:966)
org.jruby.dist/org.jruby.internal.runtime.methods.AliasMethod.call(AliasMethod.java:131)
org.jruby.dist/org.jruby.internal.runtime.methods.AliasMethod.call(AliasMethod.java:131)
org.jruby.dist/org.jruby.internal.runtime.methods.AliasMethod.call(AliasMethod.java:131)
org.jruby.dist/org.jruby.internal.runtime.methods.AliasMethod.call(AliasMethod.java:131)
org.jruby.dist/org.jruby.internal.runtime.methods.AliasMethod.call(AliasMethod.java:131)
org.jruby.dist/org.jruby.internal.runtime.methods.AliasMethod.call(AliasMethod.java:131)
org.jruby.dist/org.jruby.internal.runtime.methods.AliasMethod.call(AliasMethod.java:131)
org.jruby.dist/org.jruby.internal.runtime.methods.AliasMethod.call(AliasMethod.java:131)
org.jruby.dist/org.jruby.internal.runtime.methods.AliasMethod.call(AliasMethod.java:131)
org.jruby.dist/org.jruby.internal.runtime.methods.AliasMethod.call(AliasMethod.java:131)
org.jruby.dist/org.jruby.runtime.Helpers.invokeSuper(Helpers.java:955)
org.jruby.dist/org.jruby.ext.cgi.escape.CGIEscape.cgiesc_unescape_html(CGIEscape.java:421)
These issues cause all of the tests to fail if the pure-Ruby tests run first due to the damage it causes to those aliased methods. I am unsure if this is a recent regression, since our older version of CGI::Escape avoided making these super calls.