Sample

Autoload constants with Zeitwerk and work out why a correctly written class raises Zeitwerk::NameError, what the error does and does not tell you, and what eager loading really catches

sha256:fe3c29ae9cd4ff1fa9203d040133804b1057836934a88d30aab4c109c86f7647

Case

Goal

Autoload constants with Zeitwerk and work out why a correctly written class raises Zeitwerk::NameError, what the error does and does not tell you, and what eager loading really catches HOW

Packages

zeitwerk 2.8.3

Environment

ruby 3

Created

2026-08-14T20:49:04Z

Contract

• assert a conventionally named file installs a pending autoload at setup and runs its body only on the first reference, and that const_defined? cannot tell the two states apart while autoload? can
• assert Zeitwerk::Inflector#camelize is plain underscore camelization, so http_client.rb owes HttpClient and not HTTPClient, with no special case for acronyms
• assert a file that defines the acronym spelling instead raises Zeitwerk::NameError whose message is exactly the file plus the constant Zeitwerk expected, whose name is that expected constant, and which never mentions the constant the file actually defined
• assert the failed autoload still leaves the wrongly named constant loaded and the file in $LOADED_FEATURES, removes the autoload, and degrades the second reference to a plain uninitialized-constant NameError
• assert plain Object.autoload ends in the same state as Zeitwerk for a file that defines the wrong constant, and only keeps the constant pending when the require raises, which is the shape Zeitwerk removes the autoload for
• assert an inflector override replaces the derived name outright so APIGateway autoloads, ApiGateway is never registered, and eager_load then passes
• assert a file that defines no constant at all fails with the same Zeitwerk::NameError after its body has already run
• assert eager_load aborts on the first mismatch in sorted order rather than reporting every mismatch, leaving the later broken file unopened, and that a second run reports the next one
• assert all_expected_cpaths returns the whole path to expected constant map for the tree in one call without loading anything
• assert a directory can be managed by only one loader, and that the second push_dir raises Zeitwerk::Error naming the directory before setup is ever called
• assert zeitwerk 2.8.3 ships no C extension and no runtime dependency, which is why the newest release installs on an image with no compiler

Files

• Gemfile
• Gemfile.lock
• csx.json
• src/autoloading.rb
• src/trees/aftermath/soap_client.rb
• src/trees/audit/oauth_token.rb
• src/trees/audit/sql_builder.rb
• src/trees/audit/user_record.rb
• src/trees/claimed/widget.rb
• src/trees/conventional/json_parser.rb
• src/trees/eager/csv_writer.rb
• src/trees/eager/plain_report.rb
• src/trees/eager/xml_writer.rb
• src/trees/inflected/api_gateway.rb
• src/trees/mismatch/http_client.rb
• src/trees/plain_ruby/legacy_uri.rb
• src/trees/plain_ruby/raises_on_load.rb
• src/trees/silent/audit_log.rb
• test/contract.rb

Download the verified artifact (tar.gz) — the exact bytes the contract ran against

Origin Seeder

anonymous

Verification receipts

• ruby 3 · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · gem@1 · 2026-08-14 · ed25519:a2ec939a4c60e243