{"record":{"id":"dcb5493bf31176d8","repo":"NationalSecurityAgency/ghidra","slug":"region-is-from-a-forked-snapshot","errorCode":null,"errorMessage":"Region is from a forked snapshot","messagePattern":"Region is from a forked snapshot","errorType":"exception","errorClass":"UnsupportedOperationException","httpStatus":null,"severity":"error","filePath":"Ghidra/Debug/Framework-TraceModeling/src/main/java/ghidra/trace/database/program/DBTraceProgramViewMemoryRegionBlock.java","lineNumber":63,"sourceCode":"\n\t@Override\n\tprotected AddressSpace getAddressSpace() {\n\t\treturn region.getRange(snap).getAddressSpace();\n\t}\n\n\t@Override\n\tpublic AddressRange getAddressRange() {\n\t\treturn region.getRange(snap);\n\t}\n\n\tprotected void checkSnapOnSet() {\n\t\tlong snap = program.getSnap();\n\t\tif (snap != this.snap) {\n\t\t\t/**\n\t\t\t * TODO: Copy the region to here? It would immediately invalidate this block, but I\n\t\t\t * suppose that's okay, as long as the UI updates appropriately.\n\t\t\t */\n\t\t\tthrow new UnsupportedOperationException(\"Region is from a forked snapshot\");\n\t\t}\n\t}\n\n\t@Override\n\tpublic void setPermissions(boolean read, boolean write, boolean execute) {\n\t\tcheckSnapOnSet();\n\t\tregion.setRead(snap, read);\n\t\tregion.setWrite(snap, write);\n\t\tregion.setExecute(snap, execute);\n\t}\n\n\t@Override\n\tpublic int getFlags() {\n\t\tint bits = 0;\n\t\tfor (TraceMemoryFlag flag : region.getFlags(snap)) {\n\t\t\tbits |= flag.getBits();\n\t\t}\n\t\treturn bits;","sourceCodeStart":45,"sourceCodeEnd":81,"githubUrl":"https://github.com/NationalSecurityAgency/ghidra/blob/d5f144c24d6bc53c9cbf4448c6d11143e7696206/Ghidra/Debug/Framework-TraceModeling/src/main/java/ghidra/trace/database/program/DBTraceProgramViewMemoryRegionBlock.java#L45-L81","documentation":"Thrown as UnsupportedOperationException by checkSnapOnSet (used by setPermissions and other mutators) when the program view's current snap differs from the snap at which the region block was created. Region state is snap-specific in traces, so mutating a region block built for snap X while the view sits at snap Y is disallowed to prevent corrupting a different snapshot's view.","triggerScenarios":"Creating a DBTraceProgramViewMemoryRegionBlock at snap A, then calling setPermissions/set on it after the program view has moved to snap B (snap != this.snap).","commonSituations":"Navigating the view to a different snap after binding a region block handle. Forking snapshots and then operating on a block handle captured before the fork. Long-lived block references used across snap switches.","solutions":["Re-acquire the region block at the current snap before mutating: ensure program.getSnap() == block.snap.","Set the view's snap back to the block's snap before calling mutators.","Capture the snap with the block and only mutate within the same snap context; avoid caching block handles across snap changes."],"exampleFix":"// before\nblock.setPermissions(true, false, true); // throws if view moved snaps\n\n// after\nif (program.getSnap() == blockSnap) {\n    block.setPermissions(true, false, true);\n} else {\n    // re-fetch block at current snap, or set view snap\n}","handlingStrategy":"validation","validationCode":"// Only mutate the region block at the snap it was created\nif (program.getSnap() == blockSnap) {\n    block.setPermissions(r, w, x);\n} else {\n    // re-fetch block at current snap or set the view snap\n}","typeGuard":null,"tryCatchPattern":null,"preventionTips":["Capture the snap with the region block and only mutate at that snap.","Do not cache block handles across snap switches.","Re-acquire blocks at the current snap before mutating."],"tags":["trace-modeling","region","snapshot","fork","unsupported-operation","ghidra"],"backgroundTag":null,"analyzedSha":"d5f144c24d6bc53c9cbf4448c6d11143e7696206","analyzedAt":"2026-08-14T01:00:57.564Z","schemaVersion":2},"datasetVersion":"2026-08-14T05:17:29.042Z"}