Return completions lazily for massive savings #2217
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This is the second completions performance issue (after #2215) uncovered by upgrading Sigma IDE from HLS 1.2 to 1.4.
The problem is that
getCompletionsreturns the completions strictly, only to have them cropped tomaxCompletionsin hls-plugin-api. This is bad because there is an O(nlogn)nubOrdByin the result thunk, and it can take a second or more to nub >100k results.Thankfully
nubOrdByis lazy in the result so the fix is simple. By restoring result laziness ingetCompletions, only up tomaxCompletionsresults are processed bynubOrdBy.