perf(console): read the clock and pad a line through return slots - #1358
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Four spots still captured a value through `$( )` where the return-slot variant was already sitting next door. `rpad` is fork-free inside, so the subshell around it was its entire cost: 0.74ms per test wherever per-test timing is on, which is Bash 5 by default and any shell with --show-execution-time. It gets a `rpad_to_slot`, and `rpad` becomes the thin echo wrapper, the same shape `strip_ansi` has over `strip_ansi_to_slot`. Padding is a slice of a doubled run of spaces rather than a `printf`, because the only fork-free printf into a variable is `printf -v`, which is Bash 3.1 and this project floors at 3.0. The file hooks read the clock four times per file through `$( )`, which on Bash 3.2 wraps a `perl` fork: 5.6ms per file with both hooks, over 115 such files here. `run_test` was converted to `now_to_slot` already; these and `clock::init` were missed. The slot variant must produce exactly what the capture produced, with the trailing newline `$( )` stripped, so the tests compare the two on plain, empty, ANSI-coloured, truncating and over-1024-character input -- the last because that is where strip_ansi_to_slot changes strategy. Closes #1348 Claude-Session: https://claude.ai/code/session_01EXYWTGLjf7qM8Ru3GakDRm
This was referenced Sep 9, 2026
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🤔 Background
Related #1348
Four spots still captured a value through
$( )where the house return-slot variant already existed next door.rpadis fork-free inside, so the subshell around it was its whole cost; the file hooks read the clock four times per file, which on Bash 3.2 wraps aperlfork.💡 Changes
bashunit::str::rpad_to_slotand use it on the per-test line;rpadbecomes the thin echo wrapper, the shapestrip_ansialready has. Saves 0.74ms per test wherever per-test timing is on.printf— the only fork-free printf into a variable isprintf -v, which is Bash 3.1.clock::inittonow_to_slot. A file defining both hooks costs 5.6ms less on Bash 3.2; this repo has 115 of them.strip_ansi_to_slotchanges strategy.https://claude.ai/code/session_01EXYWTGLjf7qM8Ru3GakDRm