scripts: compliance: Add basic cmake style checks

It is very common to see a comment stating that the
"No Space Before Opening Brackets" style guide is not followed.
To avoid putting this burdon on reviewers, let the compliance
check catch this instead.

Checking for tab indentation was also very simple, so also added
this.

Running this check on all files finds many violations:
 - Space before opening brackets: 141 violations
 - Tab indentation: 420 violations

Fixing these will not be done as part of this PR. Adding the check
will prevent us from adding new violations.

Signed-off-by: Rubin Gerritsen <[email protected]>

Author: rugeGerritsen

scripts/ci/check_compliance.py

@@ -1723,6 +1723,34 @@ def filter_py(root, fnames):
                              mime=True) == "text/x-python")]
 
 
+class CMakeStyle(ComplianceTest):
+    """
+    Checks cmake style added/modified files
+    """
+    name = "CMakeStyle"
+    doc = "See https://docs.zephyrproject.org/latest/contribute/style/cmake.html for more details."
+
+    def run(self):
+        # Loop through added/modified files
+        for fname in get_files(filter="d"):
+            if fname.endswith(".cmake") or fname == "CMakeLists.txt":
+                self.check_style(fname)
+
+    def check_style(self, fname):
+        SPACE_BEFORE_OPEN_BRACKETS_CHECK = re.compile(r"^\s*if\s+\(")
+        TAB_INDENTATION_CHECK = re.compile(r"^\t+")
+
+        with open(fname, encoding="utf-8") as f:
+            for line_num, line in enumerate(f.readlines(), start=1):
+                if TAB_INDENTATION_CHECK.match(line):
+                    self.fmtd_failure("error", "CMakeStyle", fname, line_num,
+                                      "Use spaces instead of tabs for indentation")
+
+                if SPACE_BEFORE_OPEN_BRACKETS_CHECK.match(line):
+                    self.fmtd_failure("error", "CMakeStyle", fname, line_num,
+                                      "Remove space before '(' in if() statements")
+
+
 class Identity(ComplianceTest):
     """
     Checks if Emails of author and signed-off messages are consistent.