Add Ruby 2.3 stdlib appraisal files

Author: pboling

CHANGELOG.md

@@ -31,6 +31,7 @@ Please file a bug if you notice a violation of semantic versioning.
 - Updated CI workflow maintenance: QLTY uploads now use OIDC, harden-runner is pinned to v2.19.4, and Caboose dependency installation logs are visible on failure.
 - Restored Ruby 2.3 Caboose CI bundle resolution by using the last compatible kettle development/test toolchain on that EOL runtime.
 - Kept Ruby 2.3 Caboose CI on the last compatible `gitmoji-regex` release.
+- Added the missing Ruby 2.3 modular stdlib gemfiles required by generated Caboose appraisals.
 - Replaced stale platform CI `rake magic` commands with portable spec commands.
 - Pinned `multi_xml` below 0.9 for TruffleRuby compatibility.
 - Marked EOL TruffleRuby 22.3, 23.0, and 23.1 CI as experimental because they can crash inside the interpreter during Bundler setup.

docs/file.CHANGELOG.html

@@ -86,6 +86,7 @@ <h3 id="fixed">Fixed</h3>
   <li>Updated CI workflow maintenance: QLTY uploads now use OIDC, harden-runner is pinned to v2.19.4, and Caboose dependency installation logs are visible on failure.</li>
   <li>Restored Ruby 2.3 Caboose CI bundle resolution by using the last compatible kettle development/test toolchain on that EOL runtime.</li>
   <li>Kept Ruby 2.3 Caboose CI on the last compatible <code>gitmoji-regex</code> release.</li>
+  <li>Added the missing Ruby 2.3 modular stdlib gemfiles required by generated Caboose appraisals.</li>
   <li>Replaced stale platform CI <code>rake magic</code> commands with portable spec commands.</li>
   <li>Pinned <code>multi_xml</code> below 0.9 for TruffleRuby compatibility.</li>
   <li>Marked EOL TruffleRuby 22.3, 23.0, and 23.1 CI as experimental because they can crash inside the interpreter during Bundler setup.</li>
@@ -1407,7 +1408,7 @@ <h2 id="001---2010-04-22">
 </div></div>
 
       <div id="footer">
-  Generated on Wed Jun  3 19:15:43 2026 by
+  Generated on Wed Jun  3 19:19:00 2026 by
   <a href="https://yardoc.org" title="Yay! A Ruby Documentation Tool" target="_parent">yard</a>
   0.9.44 (ruby-4.0.4).
 </div>

gemfiles/modular/erb/r2.3/default.gemfile

@@ -0,0 +1,6 @@
+# The cake is a lie.
+# erb v2.2, the oldest release, was never compatible with Ruby 2.3.
+# In addition, erb does not follow SemVer, and old rubies get dropped in a patch.
+# This means we have no choice but to use the erb that shipped with Ruby 2.3
+# /opt/hostedtoolcache/Ruby/2.3.8/x64/lib/ruby/gems/2.3.0/gems/erb-2.2.2/lib/erb.rb:670:in `prepare_trim_mode': undefined method `match?' for "-":String (NoMethodError)
+# gem "erb", ">= 2.2"   # ruby >= 2.3.0

gemfiles/modular/x_std_libs/r2.3/libs.gemfile

@@ -0,0 +1,3 @@
+eval_gemfile "../../erb/r2.3/default.gemfile"
+eval_gemfile "../../mutex_m/r2.4/v0.1.gemfile"
+eval_gemfile "../../stringio/r2.4/v0.0.2.gemfile"