{"record":{"id":"c39c9225b498aeba","repo":"go-delve/delve","slug":"could-not-load-swiss-table-index-field-v","errorCode":null,"errorMessage":"could not load swiss table index field: %v","messagePattern":"could not load swiss table index field: (.+?)","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"warning","filePath":"pkg/proc/mapiter.go","lineNumber":613,"sourceCode":"\tit.groupIdx++\n\tit.group = nil\n}\n\n// loadCurrentTable loads the table at index it.dirIdx into it.tab\nfunc (it *mapIteratorSwiss) loadCurrentTable() {\n\ttab, err := it.dirPtr.sliceAccess(int(it.dirIdx))\n\tif err != nil || tab == nil || tab.Unreadable != nil {\n\t\tit.v.Unreadable = errSwissTableCouldNotLoad\n\t\treturn\n\t}\n\n\ttab = tab.maybeDereference()\n\n\tr := &swissTable{}\n\n\tfield, err2 := tab.toField(it.tableFieldIndex)\n\tif err2 != nil {\n\t\tit.v.Unreadable = fmt.Errorf(\"could not load swiss table index field: %v\", err2)\n\t\treturn\n\t}\n\tr.index, err = field.asInt()\n\tif err != nil {\n\t\tit.v.Unreadable = fmt.Errorf(\"could not load swiss table index: %v\", err)\n\t\treturn\n\t}\n\n\tgroups, err2 := tab.toField(it.tableFieldGroups)\n\tif err2 != nil {\n\t\tit.v.Unreadable = fmt.Errorf(\"could not load swiss table groups field: %v\", err2)\n\t\treturn\n\t}\n\tr.groups, err2 = groups.toField(it.groupsFieldData)\n\tif err2 != nil {\n\t\tit.v.Unreadable = fmt.Errorf(\"could not load swiss table groups data: %v\", err2)\n\t\treturn\n\t}","sourceCodeStart":595,"sourceCodeEnd":631,"githubUrl":"https://github.com/go-delve/delve/blob/a23773e6c31361e43246bc43a424ee009679b174/pkg/proc/mapiter.go#L595-L631","documentation":"When loading a table of a swiss map, the iterator dereferences the table pointer and extracts its index field. If reading that field from memory fails, the Variable is marked Unreadable with this error before iteration can continue.","triggerScenarios":"Evaluating a swiss map whose directory table pointer or index field lives in unreadable memory — corrupted directory entries, stale iterators after resize, or missing pages in core dumps.","commonSituations":"Debugging Go 1.24+ swiss maps with mismatched delve versions; inspecting maps from incomplete core files; examining heap-corrupted programs.","solutions":["Use a delve build matching the target Go runtime version","Re-evaluate the map variable at the current stop point","Validate memory/core completeness; check for heap corruption in the target"],"exampleFix":"// before\ndlv attach <pid> # dlv built for older Go, target uses swiss maps\n// after\ngo install github.com/go-delve/delve/cmd/dlv@latest && dlv attach <pid>","handlingStrategy":"fallback","validationCode":"if v.Unreadable != nil {\n    return fmt.Errorf(\"map not readable: %v\", v.Unreadable)\n}","typeGuard":"func isReadable(v *proc.Variable) bool {\n    return v.Unreadable == nil\n}","tryCatchPattern":"if err := loadCurrentTable(it); err != nil || it.v.Unreadable != nil {\n    if it.v.Unreadable != nil && strings.Contains(it.v.Unreadable.Error(), \"could not load swiss table\") {\n        return reEvaluateAndIterate(mapExpr)\n    }\n    return it.v.Unreadable\n}","preventionTips":["Use a delve build matching the target Go version","Re-evaluate maps after program stops and resizes","Validate core dump completeness before debugging map-heavy programs"],"tags":["go","maps","swissmap","variables"],"backgroundTag":"variable-unreadable-memory","analyzedSha":"a23773e6c31361e43246bc43a424ee009679b174","analyzedAt":"2026-08-31T15:12:45.221Z","schemaVersion":2},"datasetVersion":"2026-08-31T19:17:28.585Z"}