[davesnx]

Every query-json invocation, even --version, paid about 3 ms and 8 MB of module initialisation for the REPL's terminal UI stack: mosaic.ui depends on cmarkit, whose Cmarkit_data builds its Unicode and HTML-entity tables eagerly at startup. On the small benchmark files that made jq 1.7 and jaq three to four times faster than query-json, purely on process startup.

This moves the REPL into its own executable, query-json-repl, and keeps query-json --repl working by launching the sibling binary (next to the executable first, then on PATH; a missing binary prints a hint and exits 127). The JSON-loading cases for file, inline and stdin input move unchanged into cli/repl.ml; the TUI module becomes Repl_ui.mlx so the entry point can own the Repl module name. Release zips, scripts/install.sh and the npm postinstall ship both binaries.

Startup, hyperfine -N --warmup 5 --min-runs 40, release builds, Linux x86-64, OCaml 5.5.0~beta1, base 0f5ca93 vs head dbbafcb:

Command	mean ± σ
query-json -n 1 at 0f5ca93	4.4 ± 0.5 ms
query-json -n 1 at dbbafcb	1.6 ± 0.3 ms
jq -n 1 (1.7)	1.8 ± 0.3 ms
jaq -n 1 (3.1.1)	1.8 ± 0.2 ms

Allocation at exit (OCAMLRUNPARAM=v=0x400) drops from 1,063,863 to 20,074 words; cli.exe shrinks from 14.2 MB to 8.1 MB and nm finds no camlMosaic* or camlCmarkit* symbols in it. A hello world linked with cmarkit alone starts in 3.1 ms, which isolates the cost.

Checks at dbbafcb: dune build @runtest @fmt (797 runtime, 77 reader, CLI Cram incl. a new --repl case that runs through the shim) exit 0; release @all exit 0; git diff --check clean.

Review note: the two-binary release path (.github/workflows/ci.yml, scripts/install.sh, scripts/make-npm-release.js, scripts/release-postinstall.js) only runs on a tagged build and is not exercised locally.

Risk: two-way door. A merge revert restores the single-binary CLI and packaging; nothing outside the repository changes.

[davesnx]

Independent review of dbbafcb against main (0f5ca93). Built with dune build -p query-json @install, ran @runtest @fmt (exit 0, 797 tests), exercised both binaries directly, and re-measured startup with hyperfine -N (20 runs: about 2x faster at -n 1, same direction and magnitude as the table above).

Findings (inline): three should-fix, one nit. None blocks the split itself; the sibling lookup and the install.sh -r <old-tag> regression are the two worth fixing before merge.

Checked and clean

• cli/repl.ml matches the four positional cases of the old cli.ml arm by arm, including <inline>/<stdin> labels, error printing, exit codes, and the parse-then-reconnect TTY order.
• Piped stdin reaches the REPL through the sh -c hop; Filename.quote_command handles inline JSON with spaces and commas.
• dune: no module overlap between the two executables, Repl_ui.mlx builds under the mlx dialect, cli/test/dune depends on both binaries.
• nm finds no camlMosaic*/camlCmarkit* symbols in cli.exe; size 14 MB to 8.1 MB as stated.
• Pre-existing, not introduced here: the CI "Upload artifacts" step runs only on ubuntu-latest while the release step later expects macOS and Windows artifacts; Windows zips drop the .exe extension. Both are byte-identical on main.

[davesnx]

should-fix. Sys.executable_name resolves through symlinks (/proc/self/exe on Linux), so for any symlink-based install the sibling check looks in the wrong directory and only the PATH fallback saves it. Reproduced with dune's own install tree:

$ readlink -f _build/install/default/bin/query-json
.../_build/default/cli/cli.exe          # directory holds repl.exe, not query-json-repl
$ _build/install/default/bin/query-json --repl . cli/test/mock.json </dev/null
sh: 1: query-json-repl: not found
query-json-repl was not found. Install it next to query-json or on PATH.
exit 127

The shipped zip, install.sh and the npm postinstall place real files side by side, so they are fine; stow/nix/asdf-style layouts are not. Suggest also trying Filename.dirname Sys.argv.(0) (the path as invoked) before falling back to PATH.

[davesnx]

Fixed in 34c0986: the shim now resolves the binary itself, trying the directory of argv.(0) (when it has one), the directory of Sys.executable_name, then each PATH entry, and only then calls Sys.command with the absolute path. Verified: dune symlinked install tree with PATH= empty launches the REPL; a stray ./query-json-repl in the current directory is not picked up when query-json is found via PATH.

[davesnx]

should-fix. Sys.command goes through cmd.exe on Windows, where a missing program exits with 9009, not 127, so the hint is never printed on the Windows build that CI ships. Check code = 127 || code = 9009, or branch on Sys.win32.

nit. On Unix the shell prints its own sh: 1: query-json-repl: not found before the friendly hint. Checking Sys.file_exists on the resolved candidate (or searching PATH yourself) before calling Sys.command would avoid the double message.

[davesnx]

Fixed in 34c0986: no shell is involved in the lookup any more, so the 127-vs-9009 difference and the extra sh: not found line are both gone. A missing binary prints only the hint and exits 127 on every platform; the extension is .exe only when Sys.win32.

[davesnx]

should-fix. The script runs under set -e (line 3). Pinning an older release with -r <tag> downloads a single-binary zip, so this mv fails after query-json was already moved and before the chmod runs, leaving a half-installed, non-executable binary:

mv: cannot stat '.../query-json-repl': No such file or directory

Guard with [ -f "$DOWNLOAD_DIR/query-json-repl" ] && mv ..., or state in the script that -r only supports releases from this change onward.

[davesnx]

Fixed in 34c0986: query-json is moved and made executable first; query-json-repl is moved only if the zip contained it. Re-ran the sequence against a single-binary directory: exit 0, query-json installed and executable.