check_compliance.py: Simplify Kconfig tests with git() helper

Use the git() helper instead instead of subprocess.Popen to get rid of
some code duplication.

Also add some more comments to the Kconfig tests.

Signed-off-by: Ulf Magnusson <[email protected]>

Author: ulfalizer

scripts/check_compliance.py

@@ -29,17 +29,18 @@
 logger = None
 
 
-def git(*args):
+def git(*args, cwd=None):
     # Helper for running a Git command. Returns the rstrip()ed stdout output.
     # Called like git("diff"). Exits with SystemError (raised by sys.exit()) on
-    # errors.
+    # errors. 'cwd' is the working directory to use (default: current
+    # directory).
 
     git_cmd = ("git",) + args
     git_cmd_s = " ".join(shlex.quote(word) for word in git_cmd)  # For errors
 
     try:
         git_process = subprocess.Popen(
-            git_cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+            git_cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, cwd=cwd)
     except OSError as e:
         err("failed to run '{}': {}".format(git_cmd_s, e))
 
@@ -365,35 +366,22 @@ def check_no_undef_outside_kconfig(self, kconf):
         #  - {, e.g. for Python scripts ("CONFIG_FOO_{}_BAR".format(...)")
         #
         #  - *, meant for comments like '#endif /* CONFIG_FOO_* */
-        #
-        # We skip doc/releases, which often references removed symbols.
-
-        # Warning: Needs to work with both --perl-regexp and the 're' module
-        regex = r"\bCONFIG_[A-Z0-9_]+\b(?!\s*##|[$@{*])"
 
-        grep_cmd = ["git", "grep", "--line-number", "-I", "--null",
-                    "--perl-regexp", regex,
-                    "--", ":!doc/releases"]
+        defined_syms = get_defined_syms(kconf)
 
-        grep_process = subprocess.Popen(grep_cmd,
-                                        stdout=subprocess.PIPE,
-                                        stderr=subprocess.PIPE,
-                                        cwd=ZEPHYR_BASE)
+        # Maps each undefined symbol to a list <filename>:<linenr> strings
+        undef_to_locs = collections.defaultdict(list)
 
-        grep_stdout, grep_stderr = grep_process.communicate()
-        # Fail if there's anything on stderr too, so that it doesn't get missed
-        if grep_process.returncode or grep_stderr:
-            self.error("'{}' failed with exit code {} (while searching for "
-                       "Kconfig symbol references)\n\nstdout:\n{}\n\n"
-                       "stderr:\n{}"
-                       .format(" ".join(grep_cmd), grep_process.returncode,
-                               grep_stdout, grep_stderr))
+        # Warning: Needs to work with both --perl-regexp and the 're' module
+        regex = r"\bCONFIG_[A-Z0-9_]+\b(?!\s*##|[$@{*])"
 
-        defined_syms = get_defined_syms(kconf)
-        undef_to_locs = collections.defaultdict(list)
+        # Skip doc/releases, which often references removed symbols
+        grep_stdout = git("grep", "--line-number", "-I", "--null",
+                          "--perl-regexp", regex, "--", ":!/doc/releases",
+                          cwd=ZEPHYR_BASE)
 
         # splitlines() supports various line terminators
-        for grep_line in grep_stdout.decode("utf-8").splitlines():
+        for grep_line in grep_stdout.splitlines():
             path, lineno, line = grep_line.split("\0")
 
             # Extract symbol references (might be more than one) within the
@@ -433,37 +421,24 @@ def check_no_undef_outside_kconfig(self, kconf):
 
 
 def get_defined_syms(kconf):
-    # Returns all defined Kconfig symbols. This is complicated by samples and
-    # tests defining their own Kconfig trees. For those, just grep for
-    # 'config FOO' to find definitions. Doing it "properly" with Kconfiglib is
-    # still useful for the main tree, because some symbols are defined using
-    # preprocessor macros.
+    # Returns a set() with the names of all defined Kconfig symbols (with no
+    # 'CONFIG_' prefix). This is complicated by samples and tests defining
+    # their own Kconfig trees. For those, just grep for 'config FOO' to find
+    # definitions. Doing it "properly" with Kconfiglib is still useful for the
+    # main tree, because some symbols are defined using preprocessor macros.
 
     # Warning: Needs to work with both --extended-regexp and the 're' module
-    regex = "^\s*(menu)?config\s*([A-Z0-9_]+)\s*(#|$)"
-
-    grep_cmd = ["git", "grep", "-I", "-h", "--extended-regexp", regex,
-                "--", ":samples", ":tests"]
+    regex = r"^\s*(menu)?config\s*([A-Z0-9_]+)\s*(#|$)"
 
-    grep_process = subprocess.Popen(grep_cmd,
-                                    stdout=subprocess.PIPE,
-                                    stderr=subprocess.PIPE,
-                                    cwd=ZEPHYR_BASE)
-
-    grep_stdout, grep_stderr = grep_process.communicate()
-    # Fail if there's anything on stderr too, so that it doesn't get missed
-    if grep_process.returncode or grep_stderr:
-        self.error("'{}' failed with exit code {} (while searching for "
-                   "Kconfig symbol definitions)\n\nstdout:\n{}\n\n"
-                   "stderr:\n{}"
-                   .format(" ".join(grep_cmd), grep_process.returncode,
-                           grep_stdout, grep_stderr))
+    # Grep samples/ and tests/ for symbol definitions
+    grep_stdout = git("grep", "-I", "-h", "--extended-regexp", regex, "--",
+                      ":samples", ":tests")
 
+    # Start with the symbols from the main Kconfig tree in 'res'
     res = set(sym.name for sym in kconf.unique_defined_syms)
-
-    for def_line in grep_stdout.decode("utf-8").splitlines():
+    # Add the grepped definitions from samples and tests
+    for def_line in grep_stdout.splitlines():
         res.add(re.match(regex, def_line).group(2))
-
     return res