chore(tidy3d): FXC-4466-standardize-chained-exception-messages-enforce-via-ci

[marcorudolphflex]

Ensures that we don't do blind chaining when raising exceptions to have expressive errors logs in the GUI.
Same question as in #3093 :

• do we want to do that in the pre-commit-hook? Or only CI?

Greptile Overview

Greptile Summary

This PR standardizes exception chaining across the codebase by ensuring that when exceptions are re-raised using raise NewError(...) from e, the original exception context is included in the error message using {e!s} formatting. This prevents "blind chaining" where the original error details are lost to the user.

Key changes:

• New static analysis script (scripts/check_blind_chaining.py) using AST to detect blind exception chaining patterns
• Integrated check into both pre-commit hooks and CI pipeline to enforce this pattern going forward
• Updated 20+ exception handlers across components, plugins, and web API to include original error context
• All error messages now follow pattern: "Description of new error: {original_exception!s}"

Impact:

• Significantly improves debugging experience by preserving full error context
• Automated enforcement prevents regression
• Consistent error reporting across the entire codebase

Confidence Score: 4/5

• This PR is safe to merge with minor formatting issues
• The changes are mechanical and improve error handling without altering logic. The static analyzer is well-designed with appropriate safeguards. One minor formatting issue in sim_data.py with awkward spacing, and one potentially incorrect comment about pre-commit configuration that may confuse future maintainers
• Pay attention to tidy3d/components/data/sim_data.py for the formatting issue with space before colon

Important Files Changed

File Analysis

Filename	Score	Overview
scripts/check_blind_chaining.py	5/5	New AST-based static analyzer that detects blind exception chaining patterns where original error context is lost
.github/workflows/tidy3d-python-client-tests.yml	5/5	Added CI step to run blind chaining check as part of code quality checks
.pre-commit-config.yaml	5/5	Added pre-commit hook for blind chaining check to catch issues early in development
tidy3d/components/base.py	5/5	Updated exception messages to include original error context using {exc!s} format
tidy3d/web/api/webapi.py	5/5	Standardized exception chaining in web API error handling to preserve original error details
tidy3d/components/data/sim_data.py	4/5	Added exception context to savemat error message; minor formatting issue with space before colon

Sequence Diagram

sequenceDiagram
    participant Dev as Developer
    participant PreCommit as Pre-commit Hook
    participant CI as CI Pipeline
    participant Script as check_blind_chaining.py
    participant Code as Codebase

    Dev->>Dev: Write code with raise...from
    Dev->>PreCommit: git commit
    PreCommit->>Script: Run blind chaining check
    Script->>Code: Parse Python files with AST
    Code-->>Script: Return AST nodes
    Script->>Script: Find raise...from patterns
    Script->>Script: Check if cause variable in message
    alt Blind chaining detected
        Script-->>PreCommit: Exit 1 (fail)
        PreCommit-->>Dev: Commit blocked
        Dev->>Dev: Add {e!s} to error message
    else No issues
        Script-->>PreCommit: Exit 0 (pass)
        PreCommit-->>Dev: Commit succeeds
    end
    
    Dev->>CI: Push to remote
    CI->>Script: Run blind chaining check
    Script->>Code: Parse Python files with AST
    Code-->>Script: Return AST nodes
    Script->>Script: Validate all raise...from patterns
    alt All patterns valid
        Script-->>CI: Exit 0 (pass)
        CI-->>Dev: Build passes
    else Invalid patterns found
        Script-->>CI: Exit 1 (fail)
        CI-->>Dev: Build fails
    end

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[marcorudolphflex]

@greptile

[greptile-apps]

_{23 files reviewed, 2 comments}

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[github-actions]

Diff Coverage

Diff: origin/develop...HEAD, staged and unstaged changes

• tidy3d/components/base.py (0.0%): Missing lines 211,221
• tidy3d/plugins/autograd/functions.py (50.0%): Missing lines 54
• tidy3d/plugins/dispersion/fit.py (50.0%): Missing lines 668
• tidy3d/plugins/dispersion/web.py (0.0%): Missing lines 256,295
• tidy3d/plugins/klayout/drc/drc.py (100%)
• tidy3d/plugins/klayout/drc/results.py (100%)
• tidy3d/web/api/webapi.py (0.0%): Missing lines 124,1674

Summary

• Total: 13 lines
• Missing: 8 lines
• Coverage: 38%

tidy3d/components/base.py

Lines 207-215

  207             raise TypeError("Input must be a dict")
  208         try:
  209             type_value = obj[TYPE_TAG_STR]
  210         except KeyError as exc:
! 211             raise ValueError(f'Missing "{TYPE_TAG_STR}" in data: {exc!s}') from exc
  212         if not isinstance(type_value, str) or not type_value:
  213             raise ValueError(f'Invalid "{TYPE_TAG_STR}" value: {type_value!r}')
  214         return type_value

---

Lines 217-225

  217     def _get_registered_class(cls, type_value: str) -> type[Tidy3dBaseModel]:
  218         try:
  219             return TYPE_TO_CLASS_MAP[type_value]
  220         except KeyError as exc:
! 221             raise ValueError(f"Unknown type: {type_value}: {exc!s}") from exc
  222 
  223     @classmethod
  224     def _should_dispatch_to(cls, target_cls: type[Tidy3dBaseModel]) -> bool:
  225         """Return True if ``cls`` allows auto-dispatch to ``target_cls``."""

---

tidy3d/plugins/autograd/functions.py

Lines 50-58

  50         if not isinstance(ax, int):
  51             try:
  52                 ax = int(ax)
  53             except Exception as e:
! 54                 raise TypeError(f"Axis {ax!r} could not be converted to an integer: {e!s}") from e
  55 
  56         if not -ndim <= ax < ndim:
  57             raise ValueError(f"Invalid axis {ax} for {kind} with ndim {ndim}.")
  58         return ax + ndim if ax < 0 else ax

---

tidy3d/plugins/dispersion/fit.py

Lines 664-672

  664 
  665         try:
  666             resp.raise_for_status()
  667         except Exception as e:
! 668             raise WebError(
  669                 f"Connection to the website failed. Please provide a valid URL: {e!s}"
  670             ) from e
  671 
  672         data_url = list(

---

tidy3d/plugins/dispersion/web.py

Lines 252-260

  252             ssl_verify = False
  253             resp = requests.get(f"{url_server}/health", verify=ssl_verify)
  254             resp.raise_for_status()
  255         except Exception as e:
! 256             raise WebError(f"Connection to the server failed. Please try again: {e!s}") from e
  257 
  258         return get_headers(), ssl_verify
  259 
  260     def run(self) -> tuple[PoleResidue, float]:

---

Lines 291-299

  291                         "Fitter failed due to timeout. Try to decrease the number of tries or "
  292                         "inner iterations, or to relax the RMS tolerance."
  293                     )
  294                 )
! 295                 raise Tidy3dError(f"{msg}: {e!s}") from e
  296 
  297             raise WebError(
  298                 f"Fitter failed. Try again, tune the parameters, or contact us for more help: {e!s}"
  299             ) from e

---

tidy3d/web/api/webapi.py

Lines 120-128

  120         batch_detail = batch.detail()
  121         status = batch_detail.status.lower()
  122     except Exception as e:
  123         log.error(f"Could not retrieve batch details for '{resource_id}': {e}")
! 124         raise WebError(f"Failed to retrieve status for batch '{resource_id}': {e!s}") from e
  125 
  126     if status not in ERROR_STATES:
  127         return

---

Lines 1670-1678

  1670         console = get_logging_console()
  1671         console.log("Authentication configured successfully!")
  1672     except (WebError, HTTPError) as e:
  1673         url = "https://docs.flexcompute.com/projects/tidy3d/en/latest/index.html"
! 1674         raise WebError(
  1675             f"{e!s}\n\n"
  1676             "It looks like the Tidy3D Python interface is not configured with your "
  1677             "unique API key. "
  1678             "To get your API key, sign into 'https://tidy3d.simulation.cloud' and copy it "

---