xen/misra: xen-analysis.py: Improve the cppcheck version check

Use tuple comparison to check the cppcheck version.

Take the occasion to harden the regex, escaping the dots so that we
check for them instead of generic characters.

Suggested-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Luca Fancellu <luca.fancellu@arm.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>

xen/scripts/xen_analysis/cppcheck_analysis.py

@@ -157,7 +157,7 @@ def generate_cppcheck_deps():
             "Error occured retrieving cppcheck version:\n{}\n\n{}"
         )
 
-    version_regex = re.search('^Cppcheck (\d+).(\d+)(?:.\d+)?$',
+    version_regex = re.search('^Cppcheck (\d+)\.(\d+)(?:\.\d+)?$',
                               invoke_cppcheck, flags=re.M)
     # Currently, only cppcheck version >= 2.7 is supported, but version 2.8 is
     # known to be broken, please refer to docs/misra/cppcheck.txt
@@ -166,15 +166,10 @@ def generate_cppcheck_deps():
             "Can't find cppcheck version or version not identified: "
             "{}".format(invoke_cppcheck)
         )
-    major = int(version_regex.group(1))
-    minor = int(version_regex.group(2))
-    if major < 2 or (major == 2 and minor < 7):
+    version = (int(version_regex.group(1)), int(version_regex.group(2)))
+    if version < (2, 7) or version == (2, 8):
         raise CppcheckDepsPhaseError(
-            "Cppcheck version < 2.7 is not supported"
-        )
-    if major == 2 and minor == 8:
-        raise CppcheckDepsPhaseError(
-            "Cppcheck version 2.8 is known to be broken, see the documentation"
+            "Cppcheck version < 2.7 or 2.8 are not supported"
         )
 
     # If misra option is selected, append misra addon and generate cppcheck