feat: graceful CLI error handling for YAML and Python-block errors - #10
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Author mistakes no longer crash the CLI with a raw traceback. YAML syntax errors and exceptions raised inside `_py` blocks are now caught and presented as friendly, actionable reports that make clear the problem is in the authored document, not an ymprint bug. - Add YmprintAuthoringError hierarchy (YamlSyntaxError, PythonBlockError) - Raise these at the parse (yaml_loader) and exec (python_block) sites - error_display: compact top-and-bottom traceback truncation; maps `<string>` exec frames back to the author's block source and highlights the failing line - convert: wrap render, show a red error panel and exit 1 on authoring errors - live: redesigned two-part rich Panel (watch list + throbber over a status area) with a state-coloured border; reload failures show the error in-place instead of killing the session, cleared on the next save - throbber: red error-explosion burst on failed reload - Fix latent live bugs: undefined CONFIG_FILENAMES and locate_config_file now returns the nearest config as a full path - Remove a stray debug print that corrupted the live display - Tests for YAML/Python-block errors, convert exit code, and truncation Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
A SyntaxError fails at compile time, so exec() produces no `<string>` traceback frame — the previous formatter could only show the internal exec frame with no author context. Handle SyntaxError specially: - Use the exception's own .lineno/.text to show the offending code line - Detect the common cause of a `_py` block collapsing to a single line (writing `source:` instead of `source: |`, which folds the code) and emit an actionable hint to use a YAML block scalar - Clean up the final message (drop the redundant "(<string>, line N)") Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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Summary
Author mistakes no longer crash the CLI with a raw Python traceback. YAML syntax errors and exceptions raised inside
_pyblocks are caught and presented as friendly, compact, actionable reports that make clear the problem is in the authored document, not an ymprint bug. Genuine internal errors still propagate as normal tracebacks.What's included
Error model — new
YmprintAuthoringErrorhierarchy (errors.py):YamlSyntaxError— wrapsruamelerrors with file/line/columnPythonBlockError— wraps_pyblock exceptions, keeping the author's source + tracebackRaised at the two failure points:
yaml_loader.load_yaml()(parse) andblocks/python_block.py(exec).convert— catches authoring errors, prints a red panel titled "error in your document" and exits 1.live— redesigned as a two-regionrich.Panel:👁 YMPrint liveheader, the watched-file list, and the throbber✓ Reloaded … at <timestamp>/⟳ reloading…/ the compact errorCompact tracebacks (
error_display.py) — keep the top 2 + bottom 3 frames with a… N hidden …marker; map the<string>exec frame back to the author's block source and highlight the failing line.SyntaxErrorhandling — a compile-time error has no<string>frame, so it uses the exception's own.lineno/.text, and detects the commonsource:vssource: |folding mistake with an actionable block-scalar hint.Fixes — two latent
livebugs (undefinedCONFIG_FILENAMES;locate_config_filereturning a bare filename from the wrong ancestor) and a stray debug print that corrupted the live display.Tests
New
tests/test_cli_errors.py: YAML errors,convertexit code, Python-block runtime errors, top/bottom truncation, and both SyntaxError variants (folded vs genuine multi-line). Full suite: 66 passing.🤖 Generated with Claude Code