{"record":{"id":"f955b99cefa99511","repo":"vxcontrol/pentagi","slug":"failed-to-close-tar-writer-w","errorCode":null,"errorMessage":"failed to close tar writer: %w","messagePattern":"failed to close tar writer: %w","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"backend/pkg/tools/terminal.go","lineNumber":484,"sourceCode":"\tfilename := filepath.Base(path)\n\tfileDescriptor := &tar.Header{\n\t\tName: filename,\n\t\tMode: 0600,\n\t\tSize: int64(len(content)),\n\t}\n\terr = archiveWriter.WriteHeader(fileDescriptor)\n\tif err != nil {\n\t\treturn fmt.Errorf(\"tar archive header generation failed: %w\", err)\n\t}\n\n\t_, err = archiveWriter.Write([]byte(content))\n\tif err != nil {\n\t\treturn fmt.Errorf(\"tar archive content serialization failed: %w\", err)\n\t}\n\n\terr = archiveWriter.Close()\n\tif err != nil {\n\t\treturn fmt.Errorf(\"failed to close tar writer: %w\", err)\n\t}\n\n\tdir := filepath.Dir(path)\n\terr = t.dockerClient.CopyToContainer(ctx, containerName, dir, tarBuffer, client.CopyToContainerOptions{\n\t\tAllowOverwriteDirWithFile: true,\n\t})\n\tif err != nil {\n\t\treturn fmt.Errorf(\"container file transfer failed: %w\", err)\n\t}\n\n\treturn nil\n}\n\n// EditFile applies a unified diff to the file at path: it reads the current\n// content, applies the diff to it entirely in memory (see applyUnifiedDiff),\n// and only if every hunk applied cleanly writes the result back - a diff\n// that doesn't fully apply leaves the file untouched.\nfunc (t *terminal) EditFile(ctx context.Context, flowID int64, path, diffText string) (string, error) {","sourceCodeStart":466,"sourceCodeEnd":502,"githubUrl":"https://github.com/vxcontrol/pentagi/blob/ea665308baaff015b226f308438a68d929d0f29b/backend/pkg/tools/terminal.go#L466-L502","documentation":"tar.Writer.Close flushes the two trailing zero blocks of the tar archive. This error wraps that Close failing after the header and content were written. Like the previous cases, the sink is a bytes.Buffer, so failure almost always means an I/O/memory error while finalizing the archive; it is exceptionally rare.","triggerScenarios":"WriteFile or EditFile while the process is under severe memory pressure so that even the archive trailer write/allocation fails.","commonSituations":"OOM-adjacent conditions on small hosts; typically seen alongside the sibling 'content serialization failed' error when writing large payloads.","solutions":["Free memory / restart the backend process if the host is OOM-ing","Retry the write operation once memory pressure subsides","Reduce write payload size (chunk content across multiple files)","Inspect the wrapped cause; a deterministic Close failure on a bytes.Buffer points to a corrupted build or vendored stdlib — rebuild the backend"],"exampleFix":null,"handlingStrategy":"retry","validationCode":null,"typeGuard":null,"tryCatchPattern":"_, err := term.WriteFile(ctx, flowID, content, path)\nif err != nil && strings.Contains(err.Error(), \"failed to close tar writer\") {\n    time.Sleep(time.Second) // transient memory pressure\n    _, err = term.WriteFile(ctx, flowID, content, path)\n}","preventionTips":["Treat this as an OOM signal; alert on memory before it occurs","Avoid concurrent large writes to the same container","Restart the backend if this error appears repeatedly"],"tags":["docker","tar","memory","file-write"],"backgroundTag":"tar-archive-write-failed","analyzedSha":"ea665308baaff015b226f308438a68d929d0f29b","analyzedAt":"2026-09-01T14:16:31.421Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-08T10:18:20.063Z"}