Throw for bad param in GetParameterValue#465
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Previous behavior here was to segfault! An exception is much more user-friendly. Add the SWIG machinery for catching thrown exceptions in the SML binding libraries, too. We wrap every SML function with a try/catch. I don't know if this is actually heavy or not, but at least one implementation out there thought it was and went an alternative route where each method has to be explicitly marked to catch exceptions: https://github.com/KiCad/kicad-source-mirror/blob/47e4ebb32a1366d60649879381eac819f7c7131d/common/swig/ki_exception.i#L41 Add tests for TCL, Python and Java that demonstrate the exceptions being translated for each host language. We don't have C# tests yet T_T. Notice we did have to add the `atexit` handler back to prevent a segfault when the exception is not caught correctly; I don't know exactly why. Filed #464. Fixes #451.
| SWIG_exception(SWIG_RuntimeError, e.what()); | ||
| } | ||
| catch(...) { | ||
| SWIG_exception(SWIG_RuntimeError, "Unknown exception"); |
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We should still maybe append the exception type / value / string to give at least some information to the developer, imo.
| class StringElement ; | ||
| class WorkingMemory ; | ||
| class Identifier ; | ||
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A lot of these whitespace changes btw
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…#465) Cherry-pick of garfieldnate's PR #465. Changes GetParameterValue to throw std::invalid_argument instead of returning NULL (which caused segfaults). Adds SWIG %exception block to translate C++ exceptions to language-native exceptions (ValueError in Python, IllegalArgumentException in Java, etc.). Includes tests for Python, Java, and Tcl. Fixes #451. Co-authored-by: garfieldnate <garfieldnate@gmail.com>
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Apr 21, 2026
Follow-up to the revert of PR #465 (commit 828c80c). Re-lands the diagnostic improvement requested in issue #451 -- tell the user which parent+attribute was missing -- but uses std::cerr + NULL return instead of throwing std::invalid_argument. This matches moschmdt's own alternate suggestion in #451 ('replace the throw with a print command, e.g. cout, and do not throw an error to remain API compatible') and garfieldnate's acknowledgement that 'returning null and printing to cerr would be very easy; we already print to cerr throughout Soar'. Avoids breaking existing callers (and SWIG/Java consumers where the thrown exception was getting silently swallowed by SML event-handler frames). Also keeps the trailing-whitespace cleanup from the reverted commit. Refs #451, #465.
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Previous behavior here was to segfault! An exception is much more user-friendly.
Add the SWIG machinery for catching thrown exceptions in the SML binding libraries, too. We wrap every SML function with a try/catch. I don't know if this is actually heavy or not, but at least one implementation out there thought it was and went an alternative route where each method has to be explicitly marked to catch exceptions:
https://github.com/KiCad/kicad-source-mirror/blob/47e4ebb32a1366d60649879381eac819f7c7131d/common/swig/ki_exception.i#L41
Add tests for TCL, Python and Java that demonstrate the exceptions being translated for each host language. We don't have C# tests yet T_T.
Notice we did have to add the
atexithandler back to prevent a segfault when the exception is not caught correctly; I don't know exactly why. Filed #464.Fixes #451.