file_single_chunk: use URI::RFC2396_PARSER due to suppress obsoleted message

[Watson1978]

Which issue(s) this PR fixes:
Fixes #

What this PR does / why we need it:
Since Ruby 3.4.0, URI::DEFAULT_PARSER causes warning of warning: URI::RFC3986_PARSER.unescape is obsolete. Use URI::RFC2396_PARSER.unescape explicitly..
Ref. ruby/uri@9997c1a

• reproduce

$ bundle exec ruby -v -w -I"lib" test/plugin/test_buffer_file_single_chunk.rb -v
ruby 3.4.1 (2024-12-25 revision 48d4efcb85) +PRISM [x86_64-linux]
/home/watson/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/async-2.21.1/lib/async/task.rb:298: warning: assigned but unused variable - error
/home/watson/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/async-pool-0.10.2/lib/async/pool/controller.rb:332: warning: assigned but unused variable - error
/home/watson/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/traces-0.14.1/lib/traces/config.rb:43: warning: assigned but unused variable - error
/home/watson/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/async-http-0.86.0/lib/async/http/protocol/http1/server.rb:55: warning: assigned but unused variable - error
/home/watson/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/async-http-0.86.0/lib/async/http/protocol/http2/connection.rb:98: warning: assigned but unused variable - ignored_error
/home/watson/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/protocol-http-0.47.1/lib/protocol/http/body/stream.rb:263: warning: assigned but unused variable - buffer
/home/watson/src/fluentd/lib/fluent/plugin_helper.rb:46: warning: method redefined; discarding old inherited
/home/watson/src/fluentd/lib/fluent/plugin_helper.rb:46: warning: previous definition of inherited was here
Loaded suite test/plugin/test_buffer_file_single_chunk
Started
BufferFileSingleChunkTest: 
  chunk with file for enqueued chunk: 
    test: can load as queued chunk (read only) with metadata:																		/home/watson/src/fluentd/lib/fluent/plugin/buffer/file_single_chunk.rb:250: warning: URI::RFC3986_PARSER.unescape is obsolete. Use URI::RFC2396_PARSER.unescape explicitly.
.: (0.001127)
  chunk with file for staged chunk: 
    test: #file_rename can rename chunk files even in windows, and call callback with file size:													/home/watson/src/fluentd/lib/fluent/plugin/buffer/file_single_chunk.rb:250: warning: URI::RFC3986_PARSER.unescape is obsolete. Use URI::RFC2396_PARSER.unescape explicitly.
.: (0.000559)
    test: can be enqueued:																						/home/watson/src/fluentd/lib/fluent/plugin/buffer/file_single_chunk.rb:250: warning: URI::RFC3986_PARSER.unescape is obsolete. Use URI::RFC2396_PARSER.unescape explicitly.
.: (0.000361)
    test: can load as staged chunk from file with metadata:																		/home/watson/src/fluentd/lib/fluent/plugin/buffer/file_single_chunk.rb:250: warning: URI::RFC3986_PARSER.unescape is obsolete. Use URI::RFC2396_PARSER.unescape explicitly.
.: (0.000307)
  chunk with queued chunk file: 
    test: can load as queued chunk:																					/home/watson/src/fluentd/lib/fluent/plugin/buffer/file_single_chunk.rb:250: warning: URI::RFC3986_PARSER.unescape is obsolete. Use URI::RFC2396_PARSER.unescape explicitly.
.: (0.000431)

...(snip)...

This patch will use URI::RFC2396_PARSER instead due to suppress above warning.

• NOTE:
  • URI::RFC2396_PARSER constant was introduced since v0.12.3 which bundled in Ruby 3.2.
  • See Provide URI::RFC2396_PARSER for Ruby 3.3 or older ruby/uri#118

Docs Changes:

Release Note:

[daipom]

Thanks!
I have some concerns that this does not work on some Ruby versions.

In the following issue, URI::RFC2396_PARSER was provided to Ruby 3.2 and 3.3.

• Provide URI::RFC2396_PARSER for Ruby 3.3 or older ruby/uri#118

So, this works well on the latest 3.2.x and 3.3.x.
However, some old patch versions don't have URI::RFC2396_PARSER.
For example, this would not work on Ruby 3.2.0, right?

I would like to hear from other maintainers on this point.

[daipom]

LGTM! Thanks!