fix: preserve custom error handler continuations#366
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hjotha wants to merge 3 commits intomendixlabs:mainfrom
Open
fix: preserve custom error handler continuations#366hjotha wants to merge 3 commits intomendixlabs:mainfrom
hjotha wants to merge 3 commits intomendixlabs:mainfrom
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Symptom: custom error-handler bodies that did not explicitly return were rebuilt as detached terminal paths, while empty custom handlers could either lose their error flow or rejoin into statements that read an output variable that is absent on the error path. Root cause: the microflow builder handled custom error handlers immediately at the source activity. It did not retain pending handler state until the next safe continuation was known, and a later handler could overwrite an earlier pending handler. Fix: queue pending custom handler state, route non-terminal handlers through the next safe continuation via a merge, preserve empty custom-handler flows, and terminate output-producing handlers before output-dependent continuation statements in void microflows. Tests: added synthetic builder regressions for non-terminal handler rejoin, consecutive pending handlers, empty output-handler termination, and empty no-output-handler rejoin. Ran make build, make lint-go, and make test.
This was referenced Apr 27, 2026
Adds an MDL script under mdl-examples/bug-tests/ exercising a non-terminal custom error handler on a microflow call followed by a continuation call. After exec, `mx check` reports 0 errors, confirming the handler tail rejoins the continuation instead of becoming a detached terminal path. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Symptom: a custom error handler for an output-producing action could rejoin before a later DECLARE whose initial value referenced that output variable. Studio Pro then rejected the roundtripped microflow because the output variable is not in scope on the error-handler path. Root cause: skip-variable routing collected references from many statement kinds, but omitted DECLARE initial values. Fix: include DECLARE initial values in statement reference analysis so handlers wait for, or terminate before, output-dependent declarations. Tests: add a graph-level regression that verifies the error-handler path cannot reach an output-dependent DECLARE, plus the existing custom-handler routing tests via make build and make test.
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Closes #349.
Part of #332.
Summary
Validation
make buildmake lint-gomake test