Appendix C. Error Catalog

Purpose

Map core error conditions to statuses, markers, and exits.

Contract/gating/internal categories

Category	Marker	Exit
Contract error	CONTRACT ERROR:	2
Gating failure	GATING FAILURE:	3
Internal error	INTERNAL ERROR:	5

Refs:

• codeclone/ui_messages.py:MARKER_CONTRACT_ERROR
• codeclone/contracts.py:ExitCode

Baseline contract errors

Condition	Baseline status	CLI behavior
Missing baseline	missing	normal: empty diff; gating: exit 2
Schema mismatch	mismatch_schema_version	normal: ignore baseline; gating: exit 2
Fingerprint mismatch	mismatch_fingerprint_version	normal: ignore baseline; gating: exit 2
Python tag mismatch	mismatch_python_version	normal: ignore baseline; gating: exit 2
Integrity mismatch	integrity_failed	normal: ignore baseline; gating: exit 2

Refs:

• codeclone/cli.py:_main_impl
• codeclone/baseline.py:BaselineStatus

Cache degradation cases

Condition	Cache status	Behavior
Missing cache file	missing	proceed without cache
Version mismatch	version_mismatch	ignore cache + warning
Analysis profile mismatch (min_loc/min_stmt)	analysis_profile_mismatch	ignore cache + warning
Invalid JSON/type	invalid_json / invalid_type	ignore cache + warning
Signature mismatch	integrity_failed	ignore cache + warning
Oversized cache	too_large	ignore cache + warning

Refs:

• codeclone/cache.py:CacheStatus
• codeclone/cache.py:Cache._ignore_cache

Source IO and gating

Condition	Behavior
Source read/decode failure in normal mode	file skipped; warning; continue
Source read/decode failure in gating mode	contract error exit 2

Refs:

• codeclone/cli.py:process_file
• codeclone/cli.py:_main_impl

Report write errors

Condition	Behavior
Baseline write OSError	contract error exit 2
HTML/JSON/Markdown/SARIF/TXT write OSError	contract error exit 2

Refs:

• codeclone/cli.py:_main_impl

MCP interface errors

Condition	Behavior
Optional mcp extra missing	codeclone-mcp prints install hint and exits 2
Invalid root path / invalid numeric config	MCP service contract error
Missing run or finding id	MCP service request error
Unsupported MCP resource URI / report section	MCP service contract error

Refs:

• codeclone/mcp_server.py:main
• codeclone/mcp_service.py

Locked by tests

• tests/test_cli_inprocess.py::test_cli_report_write_error_is_contract_error
• tests/test_cli_inprocess.py::test_cli_update_baseline_write_error_is_contract_error
• tests/test_cli_inprocess.py::test_cli_unreadable_source_fails_in_ci_with_contract_error
• tests/test_cli_unit.py::test_cli_internal_error_marker
• tests/test_mcp_server.py::test_mcp_server_main_reports_missing_optional_dependency