Add goinfo builtin for version information

This new builtin identifies the go-script-bash framework, the Bash
version, and the operating system environment. Useful for bug reports.

Author: mbland

libexec/goinfo

@@ -0,0 +1,31 @@
+#! /usr/bin/env bash
+#
+# Prints go-script-bash, Bash, and operating system version information
+#
+# Useful for diagnosing problems and filing bug reports.
+#
+# More information may be gleaned from `uname`, as well as `sw_vers` on macOS,
+# but this includes the most often relevant information.
+
+. "$_GO_USE_MODULES" 'format' 'platform'
+
+_@go.gocore() {
+  local varnames=('_GO_CORE_VERSION'
+    'BASH_VERSION'
+    'OSTYPE'
+    '_GO_PLATFORM_ID'
+    '_GO_PLATFORM_VERSION_ID')
+  local values=()
+  local varname
+  local result=()
+
+  for varname in "${varnames[@]}"; do
+    values+=("${!varname}")
+  done
+
+  @go.pad_items 'varnames' "${varnames[@]/%/:}"
+  @go.zip_items 'varnames' 'values' '  ' result
+  printf '%s\n' "${result[@]}"
+}
+
+_@go.gocore "$@"

tests/goinfo.bats

@@ -0,0 +1,30 @@
+#! /usr/bin/env bats
+
+load environment
+
+setup() {
+  test_filter
+  @go.create_test_go_script '@go "$@"'
+  export __GO_ETC_OS_RELEASE="$BATS_TEST_ROOTDIR/os-release"
+}
+
+teardown() {
+  @go.remove_test_go_rootdir
+}
+
+@test "$SUITE: emit version information about framework, Bash, and OS" {
+  # Use simulated /etc/os-release to prevent computation via uname or sw_vers.
+  mkdir -p "$BATS_TEST_ROOTDIR"
+  printf '%s\n' \
+    'ID=foobar' \
+    'VERSION_ID=666' >"$__GO_ETC_OS_RELEASE"
+
+  run "$TEST_GO_SCRIPT" 'goinfo'
+  assert_success
+  assert_lines_equal \
+    "_GO_CORE_VERSION:         $_GO_CORE_VERSION" \
+    "BASH_VERSION:             $BASH_VERSION" \
+    "OSTYPE:                   $OSTYPE" \
+    '_GO_PLATFORM_ID:          foobar' \
+    '_GO_PLATFORM_VERSION_ID:  666'
+}