Merge pull request #873 from akinomyoga/check-bash-version

Check Bash version

README.md

@@ -8,8 +8,9 @@
 
 [![Join the chat in bats-core/bats-core on gitter](https://badges.gitter.im/bats-core/bats-core.svg)][gitter]
 
-Bats is a [TAP](https://testanything.org/)-compliant testing framework for Bash.  It provides a simple
-way to verify that the UNIX programs you write behave as expected.
+Bats is a [TAP](https://testanything.org/)-compliant testing framework for Bash
+3.2 or above.  It provides a simple way to verify that the UNIX programs you
+write behave as expected.
 
 A Bats test file is a Bash script with special syntax for defining test cases.
 Under the hood, each test case is just a function with a description.

bin/bats

@@ -2,6 +2,19 @@
 
 set -euo pipefail
 
+# Note: We first need to use POSIX's `[ ... ]' instead of Bash's `[[ ... ]]'
+# because this is the check for Bash, where the shell may not be Bash.  Once we
+# confirm that we are in Bash, we can use [[ ... ]] and (( ... )).  Note that
+# these [[ ... ]] and (( ... )) do not cause syntax errors in POSIX shells,
+# though they can be parsed differently.
+if [ -z "${BASH_VERSION-}" ] ||
+    [[ -z "${BASH_VERSINFO-}" ]] ||
+    ((BASH_VERSINFO[0] < 3 || (BASH_VERSINFO[0] == 3 && BASH_VERSINFO[1] < 2)))
+then
+  printf 'bats: this program needs to be run by Bash >= 3.2\n' >&2
+  exit 1
+fi
+
 if command -v greadlink >/dev/null; then
   bats_readlinkf() {
     greadlink -f "$1"

docs/CHANGELOG.md

@@ -17,6 +17,7 @@ The format is based on [Keep a Changelog][kac] and this project adheres to
 * add security.md (#762)
 * add codespell CI checks (#720)
 * dynamic test registration via `bats_test_function` (#349)
+* add check that Bats is executed with Bash >= 3.2 (#873)
 
 ### Fixed