Fix infinite loop and force-unwrap panic in scheduler cancel/remove logic#586
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joshuahannan wants to merge 1 commit intomasterfrom
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Fix infinite loop and force-unwrap panic in scheduler cancel/remove logic#586joshuahannan wants to merge 1 commit intomasterfrom
joshuahannan wants to merge 1 commit intomasterfrom
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…ogic FlowTransactionScheduler.cdc: The binary search in cancelTransaction had no break when a duplicate ID was detected, leaving low/high unchanged and creating an infinite loop that exhausted all execution effort. FlowTransactionSchedulerUtils.cdc: removeID force-unwrapped the result of firstIndex(of:) without a nil check. If the ID was absent from the ids array due to any state inconsistency, the transaction would panic. Changed to a safe if-let guard. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
joshuahannan
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janezpodhostnik
approved these changes
Mar 19, 2026
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| if midCanceledID == id { | ||
| emit CriticalIssue(message: "Invalid ID: \(id) transaction already in canceled transactions array") | ||
| break |
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should we just exit the function here?
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Summary
Two bugs found during a security audit of the scheduler contracts:
FlowTransactionScheduler.cdc—cancelTransactionuses a binary search to maintain a sortedcanceledTransactionsarray. When a duplicate ID is detected, aCriticalIssueevent was emitted but neitherlownorhighwas updated, making thewhile low < highloop infinite and exhausting all execution effort. Added abreakafter the event emit.FlowTransactionSchedulerUtils.cdc—removeIDcalledids.remove(at: index!)whereindexis the result offirstIndex(of:), which returnsnilif the element is not found. Any state inconsistency betweenidsByTimestampand the tracked transactions would cause a panic. Changed to a safeif letguard.Test plan
make test)make -C lib/go test)check-tidypasses (Go assets regenerated viamake generate)🤖 Generated with Claude Code