librt: Support specifying vec capacity during construction#21304
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librt: Support specifying vec capacity during construction#21304
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mypy_primer failures may be unrelated. |
p-sawicki
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Apr 23, 2026
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| len(expr.args) == 1 | ||
| and expr.arg_kinds == [ARG_POS] | ||
| or len(expr.args) == 2 | ||
| and expr.arg_kinds == [ARG_POS, ARG_NAMED] |
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formatting makes this expression a little confusing. add parenthesis so it's `elif ((... and ...) or (... and ...))?
| PyObject *VecNested_FromIterable(size_t item_type, size_t depth, PyObject *iterable) { | ||
| VecNested v = vec_alloc(0, item_type, depth); | ||
| PyObject *VecNested_FromIterable(size_t item_type, size_t depth, PyObject *iterable, int64_t cap) { | ||
| VecNested v = vec_alloc(cap > 0 ? cap : 0, item_type, depth); |
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could remove the ternary expression here and just pass cap i think since cap < 0 is rejected before FromIterable is called. same in other FromIterable functions.
| old = v | ||
| v = append(v, 'c') | ||
| old = append(old, 'Q') | ||
| assert v[0] == 'a' |
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seems better to check v[2] here since we would expect v to be ['a', 'b', 'c'] and old to be ['a', 'b', 'Q'].
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According to mypy_primer, this change doesn't affect type check results on a corpus of open source code. ✅ |
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Use e.g.
vec[i64](capacity=n)to reserve capacity in the buffer during construction. This can be used to reduce the number of buffer reallocs when appending items. Capacity is the length of buffer, while length is the number of items currently stored in the buffer.I used coding agent assist but did this in multiple smaller increments.