Add test_complete script to compare rg --help output to zsh completion function

ci/test_complete.sh

@@ -0,0 +1,83 @@
+#!/bin/sh
+
+# Compares options in `rg --help` output to options in zsh completion function
+
+set -e
+
+main() {
+    local rg="target/${TARGET}/release/rg"
+    local _rg='complete/_rg'
+    local ret='0'
+    local helpTemp="$( mktemp )"
+    local compTemp="$( mktemp )"
+    local diff
+
+    [ -e "${rg}" ] || rg="target/${TARGET}/debug/rg"
+
+    if [ ! -e "${rg}" ]; then
+        printf 'File not found: %s\n' "${rg}" >&2
+        ret='1'
+    elif [ ! -e "${_rg}" ]; then
+        printf 'File not found: %s\n' "${_rg}" >&2
+        ret='1'
+    else
+        # 'Parse' options out of the `--help` output. To prevent false positives
+        # we only look at lines where the first non-white-space character is `-`
+        "${rg}" --help |
+        "${rg}" -- '^\s*-' |
+        "${rg}" -io -- '[\t ,](-[a-z0-9]|--[a-z0-9-]+)\b' |
+        tr -d '\t ,' |
+        sort -u > "${helpTemp}"
+
+        # 'Parse' options out of the completion-function file. To prevent false
+        # negatives, we:
+        #
+        # * Exclude lines that look like comments
+        # * Exclude lines that don't appear to have a bracketed description
+        #   suitable for `_arguments`
+        # * Exclude those bracketed descriptions so we don't match options
+        #   which might be referenced in them
+        # * Exclude parenthetical lists of exclusive options so we don't match
+        #   those
+        #
+        # This does of course make the following assumptions:
+        #
+        # * Each option definition is on its own (single) line
+        # * Each option definition has a description
+        # * Option names are static — i.e., they aren't constructed from
+        #   variables or command substitutions. Brace expansion is OK as long as
+        #   each component of the expression is a complete option flag — in
+        #   other words, `{--foo,--bar}` is valid, but `--{foo,bar}` is not
+        "${rg}" -v -- '^\s*#' "${_rg}" |
+        "${rg}" --replace '$1' -- '^.*?(?:\(.+?\).*?)?(-.+)\[.+\].*' |
+        tr -d "\t (){}*=+:'\"" |
+        tr ',' '\n' |
+        sort -u > "${compTemp}"
+
+        diff="$(
+            if diff --help 2>&1 | grep -qF -- '--label'; then
+                diff -U2 \
+                    --label '`rg --help`' \
+                    --label "${_rg}" \
+                    "${helpTemp}" "${compTemp}" || true
+            else
+                diff -U2 \
+                    -L '`rg --help`' \
+                    -L "${_rg}" \
+                    "${helpTemp}" "${compTemp}" || true
+            fi
+        )"
+
+        [ -n "${diff}" ] && {
+            printf '%s\n' 'zsh completion options differ from `--help` options:' >&2
+            printf '%s\n' "${diff}" >&2
+            ret='1'
+        }
+    fi
+
+    rm -f "${helpTemp}" "${compTemp}"
+
+    return "${ret}"
+}
+
+main "${@}"