More robust check of bash version

CHANGES.rst

@@ -31,7 +31,8 @@ Unreleased
 -   When generating a command's name from a decorated function's name, the
     suffixes ``_command``, ``_cmd``, ``_group``, and ``_grp`` are removed.
     :issue:`2322`
-
+-   More robust bash version check, fixing problem on Windows with git-bash.
+    :issue:`2638`
 
 Version 8.1.7
 -------------

src/click/shell_completion.py

@@ -304,11 +304,18 @@ class BashComplete(ShellComplete):
     @staticmethod
     def _check_version() -> None:
         import subprocess
+        import shutil
 
-        output = subprocess.run(
-            ["bash", "-c", 'echo "${BASH_VERSION}"'], stdout=subprocess.PIPE
-        )
-        match = re.search(r"^(\d+)\.(\d+)\.\d+", output.stdout.decode())
+        bash_exe = shutil.which("bash")
+
+        if bash_exe is None:
+            match = None
+        else:
+            output = subprocess.run(
+                [bash_exe, "--norc", "-c", 'echo "${BASH_VERSION}"'],
+                stdout=subprocess.PIPE,
+            )
+            match = re.search(r"^(\d+)\.(\d+)\.\d+", output.stdout.decode())
 
         if match is not None:
             major, minor = match.groups()