fix(k8s): data race + premature output read in runCommandStreaming#238
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The stdout/stderr scanner goroutines both wrote to one strings.Builder with no synchronization (Builder isn't concurrency-safe), and output was read after cmd.Wait() without joining the goroutines — a data race and a torn/incomplete read. Guard the builder with a mutex and join both scanners via a WaitGroup, draining the pipes before cmd.Wait() per the os/exec contract. Closes #208
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Problem
runCommandStreamingspawns separate stdout and stderr scanner goroutines that both calloutput.WriteStringon a singlestrings.Builderwith no synchronization.strings.Builderis not safe for concurrent use → data race. There's also noWaitGroup, andoutput.String()is read right aftercmd.Wait(), which does not join the scanners — so the read can be torn/incomplete.Where
internal/k8s/plan/exec.go:300-337(runCommandStreaming)Fix
strings.Builderwith async.Mutex.sync.WaitGroupand drain the pipes (wg.Wait()) beforecmd.Wait(), per theos/execdocs ("it is incorrect to call Wait before all reads from the pipe have completed").Testing
go build ./internal/k8s/...,go vet, andgo test -race ./internal/k8s/plan/all pass.Closes #208