refactor: convert json_encode_item() from recursive to iterative#19839
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mattn wants to merge 2 commits intovim:masterfrom
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refactor: convert json_encode_item() from recursive to iterative#19839mattn wants to merge 2 commits intovim:masterfrom
mattn wants to merge 2 commits intovim:masterfrom
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Replace recursive json_encode_item() with an explicit stack-based iterative implementation. This prevents stack overflow on deeply nested JSON structures and improves safety for LSP, ch_listen(), and other external data sources. The explicit stack (json_enc_frame_T) tracks list/tuple/dict iterator state. On error, all pending copyIDs are properly cleaned up, which the recursive version did not do.
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Replace encode_value/item_done goto labels with for(;;) loops. The outer loop replaces goto encode_value (via continue), and the inner loop replaces goto item_done (via an advance flag to break back to the outer loop when the next value is ready).
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Convert
json_encode_item()from a recursive implementation to an iterative one using an explicit stack (garray_Tofjson_enc_frame_Tframes).The recursive version uses C call stack proportional to nesting depth, which can cause a stack overflow (segfault) on deeply nested structures even when
maxfuncdepthis set high enough to allow it. The iterative version uses heap-allocated frames, so nesting depth is limited only by available memory.Benchmark comparison (average of 3 runs, ops/sec):
No performance regression. Complex structures (mixed, dict_100) show improvement.