{"record":{"id":"cf8732afc8ea9db7","repo":"cloudflare/cloudflared","slug":"expected-system-information-to-have-d-fields-got","errorCode":null,"errorMessage":"expected system information to have %d fields got %d: %w","messagePattern":"expected system information to have (.+?) fields got (.+?): %w","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"diagnostic/system_collector_utils.go","lineNumber":142,"sourceCode":"\nfunc ParseUnameOutput(output string, system string) (*OsInfo, error) {\n\tconst (\n\t\tosystemField               = 0\n\t\tnameField                  = 1\n\t\tosVersionField             = 2\n\t\tosReleaseStartField        = 3\n\t\tosInformationFieldsMinimum = 6\n\t\tdarwin                     = \"darwin\"\n\t)\n\n\tarchitectureOffset := 2\n\tif system == darwin {\n\t\tarchitectureOffset = 1\n\t}\n\n\tfields := strings.Fields(output)\n\tif len(fields) < osInformationFieldsMinimum {\n\t\treturn nil, fmt.Errorf(\"expected system information to have %d fields got %d: %w\",\n\t\t\tosInformationFieldsMinimum, len(fields), ErrInsuficientFields,\n\t\t)\n\t}\n\n\tarchitectureField := len(fields) - architectureOffset\n\tosystem := fields[osystemField]\n\tname := fields[nameField]\n\tosVersion := fields[osVersionField]\n\tosRelease := strings.Join(fields[osReleaseStartField:architectureField], \" \")\n\tarchitecture := fields[architectureField]\n\n\treturn &OsInfo{\n\t\tosystem,\n\t\tname,\n\t\tosVersion,\n\t\tosRelease,\n\t\tarchitecture,\n\t}, nil","sourceCodeStart":124,"sourceCodeEnd":160,"githubUrl":"https://github.com/cloudflare/cloudflared/blob/2253eeeb25a44a713a4b60b8ba1e1b3f377d1a0f/diagnostic/system_collector_utils.go#L124-L160","documentation":"ParseUnameOutput parses `uname -a` output and requires at least `osInformationFieldsMinimum` whitespace-separated fields to derive system, hostname, and architecture. If the uname output is too short, it returns ErrInsuficientFields wrapped in this message. On darwin an architectureOffset of 1 shifts the architecture field index because macOS uname output has a different shape.","triggerScenarios":"Calling ParseUnameOutput (directly or via collectOSInformationUnix during Collect) with empty, truncated, or stubbed `uname -a` output — e.g. uname failing partially, a mock/minimal environment printing nothing, or capturing only part of the output.","commonSituations":"Minimal containers with a stub uname, calling uname without the -a flag so output lacks fields, trailing-newline-only output on broken hosts, or feeding output from a different command (e.g. plain `uname`) into the parser.","solutions":["Ensure the collector invokes `uname -a` (all fields) and capture stderr to confirm the command succeeded before parsing.","Verify `uname -a` output manually on the affected host; if it is truncated, fix the host environment or uname binary.","Guard the caller against empty output (skip parsing when strings.TrimSpace(output) is empty).","On darwin hosts confirm the darwin-specific architectureOffset path matches the actual uname format for the OS version."],"exampleFix":"// before\nout, _ := exec.Command(\"uname\").Output()\ninfo, err := diagnostic.ParseUnameOutput(string(out))\n// after\nout, err := exec.Command(\"uname\", \"-a\").Output()\nif err != nil {\n\treturn err\n}\nif len(strings.Fields(string(out))) < 3 {\n\treturn fmt.Errorf(\"uname output too short: %q\", string(out))\n}\ninfo, err := diagnostic.ParseUnameOutput(string(out))","handlingStrategy":"validation","validationCode":"func validateUnameOutput(output string) error {\n\tfields := strings.Fields(output)\n\tif len(fields) < 3 {\n\t\treturn fmt.Errorf(\"uname output too short (%d fields): %q\", len(fields), output)\n\t}\n\treturn nil\n}","typeGuard":null,"tryCatchPattern":"info, err := diagnostic.ParseUnameOutput(unameOut)\nvar target error = diagnostic.ErrInsuficientFields\nif errors.Is(err, target) {\n\tlog.Warn().Str(\"output\", unameOut).Msg(\"uname output malformed; skipping OS info\")\n} else if err != nil {\n\treturn fmt.Errorf(\"uname parse failed: %w\", err)\n}","preventionTips":["Run `uname -a` (not plain `uname`) and check its exit code before parsing.","Reject empty or whitespace-only output before calling the parser.","Account for the darwin-specific field offset when testing on macOS.","Capture stderr from uname to detect partial failures early."],"tags":["parsing","uname","diagnostics","os-information"],"backgroundTag":"unexpected-response-shape","analyzedSha":"2253eeeb25a44a713a4b60b8ba1e1b3f377d1a0f","analyzedAt":"2026-09-06T04:14:33.757Z","contentChangedAt":"2026-09-06T04:14:33.757Z","schemaVersion":2},"datasetVersion":"2026-09-14T00:17:10.932Z"}