fix: correct qcow2 streaming conversion to device#3
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The previous change introduced two critical bugs: 1. Used a local `qemuCmd` variable instead of assigning to `cmd`, leaving `cmd` nil and causing a nil-pointer dereference at the logging and execution lines below the switch. 2. Even with the variable name corrected, `cmd.CombinedOutput()` overrides any prior `cmd.Stdout` assignment, so the device file redirect was silently discarded and no data would reach the volume. Fix by: - Assigning directly to `cmd` in the qcow2 case. - Detecting whether stdout has been redirected after the switch and using `cmd.Run()` + a separate stderr buffer in that path, leaving `cmd.CombinedOutput()` for the raw/dd path. - Using a checked defer for `deviceFile.Close()`. - Adding the required `//nolint:gosec,noctx` annotation.
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Summary
qcow2case assigned to a localqemuCmdvariable instead ofcmd, leavingcmdnil. The logging (cmd.Args) and execution (cmd.CombinedOutput()) lines below the switch would panic at runtime.cmd.CombinedOutput()unconditionally sets bothStdoutandStderr, silently overriding thecmd.Stdout = deviceFileredirect — no data would reach the LVM volume.noctx: Missing//nolint:gosec,noctxon the newexec.Commandcall.errcheck:defer deviceFile.Close()did not check the error return.Fix
cmdin theqcow2case (not a local variable).cmd.Stdout != nilto choose the execution path:cmd.Run()with a separatebytes.Bufferoncmd.Stderrso stdout continues flowing to the device file and stderr is still captured for error reporting.cmd.CombinedOutput().deferclosure fordeviceFile.Close().//nolint:gosec,noctxannotation.Test plan
go build ./...passesgo test ./...passes (all packages)golangci-lint run ./internal/lvm/...reports 0 issues