Make warnings available in a list

Also make printing of warnings to stderr optional. It's on by default,
since it's almost always what you want.

This makes printing and processing of warnings more flexible, compared
to always printing warnings to stderr as soon as they're generated. It
was inspired by wanting to promote certain warnings to errors in Zephyr,
which previously required capturing stderr.

2 files changed, 65 insertions, 18 deletions

diff --git a/kconfiglib.py b/kconfiglib.py
index 7261890..9a6c9cc 100644
--- a/kconfiglib.py
+++ b/kconfiglib.py
@@ -479,6 +479,19 @@ class Kconfig(object):
       C tools). Can be changed with the 'mainmenu' statement (see
       kconfig-language.txt).
 
+    warnings:
+      A list of strings containing all warnings that have been generated. This
+      allows flexibility in how warnings are printed and processed.
+
+      See the 'warn_to_stderr' parameter to Kconfig.__init__() and the
+      Kconfig.enable/disable_stderr_warnings() functions as well. Note that
+      warnings still get added to Kconfig.warnings when 'warn_to_stderr' is
+      True.
+
+      Just as for warnings printed to stderr, only optional warnings that are
+      enabled will get added to Kconfig.warnings. See the various
+      Kconfig.enable/disable_*_warnings() functions.
+
     srctree:
       The value of the $srctree environment variable when the configuration was
       loaded, or None if $srctree wasn't set. Kconfig and .config files are
@@ -506,6 +519,7 @@ class Kconfig(object):
         "_warn_for_no_prompt",
         "_warn_for_redun_assign",
         "_warn_for_undef_assign",
+        "_warn_to_stderr",
         "_warnings_enabled",
         "config_prefix",
         "const_syms",
@@ -518,6 +532,7 @@ class Kconfig(object):
         "srctree",
         "syms",
         "top_node",
+        "warnings",
         "y",
 
         # Parsing-related
@@ -537,7 +552,7 @@ class Kconfig(object):
     # Public interface
     #
 
-    def __init__(self, filename="Kconfig", warn=True):
+    def __init__(self, filename="Kconfig", warn=True, warn_to_stderr=True):
         """
         Creates a new Kconfig object by parsing Kconfig files. Raises
         KconfigSyntaxError on syntax errors. Note that Kconfig files are not
@@ -557,13 +572,23 @@ class Kconfig(object):
           set. See the class documentation.
 
         warn (default: True):
-          True if warnings related to this configuration should be printed to
-          stderr. This can be changed later with
-          Kconfig.enable/disable_warnings(). It is provided as a constructor
-          argument since warnings might be generated during parsing.
+          True if warnings related to this configuration should be generated.
+          This can be changed later with Kconfig.enable/disable_warnings(). It
+          is provided as a constructor argument since warnings might be
+          generated during parsing.
 
           See the other Kconfig.enable_*_warnings() functions as well, which
           enable or suppress certain warnings when warnings are enabled.
+
+          All generated warnings are added to the Kconfig.warnings list. See
+          the class documentation.
+
+        warn_to_stderr (default: True):
+          True if warnings should be printed to stderr in addition to being
+          added to Kconfig.warnings.
+
+          This can be changed later with
+          Kconfig.enable/disable_stderr_warnings().
         """
         self.srctree = os.environ.get("srctree")
 
@@ -584,10 +609,14 @@ class Kconfig(object):
                        _RE_ASCII).match
 
 
+        self.warnings = []
+
         self._warnings_enabled = warn
+        self._warn_to_stderr = warn_to_stderr
         self._warn_for_undef_assign = False
         self._warn_for_redun_assign = True
 
+
         self.syms = {}
         self.const_syms = {}
         self.defined_syms = []
@@ -1311,11 +1340,23 @@ class Kconfig(object):
         """
         self._warnings_enabled = False
 
+    def enable_stderr_warnings(self):
+        """
+        See Kconfig.__init__().
+        """
+        self._warn_to_stderr = True
+
+    def disable_stderr_warnings(self):
+        """
+        See Kconfig.__init__().
+        """
+        self._warn_to_stderr = False
+
     def enable_undef_warnings(self):
         """
-        Enables warnings for assignments to undefined symbols. Printed to
-        stderr. Disabled by default since they tend to be spammy for Kernel
-        configurations (and mostly suggests cleanups).
+        Enables warnings for assignments to undefined symbols. Disabled by
+        default since they tend to be spammy for Kernel configurations (and
+        mostly suggests cleanups).
         """
         self._warn_for_undef_assign = True
 
@@ -1352,7 +1393,10 @@ class Kconfig(object):
             "srctree not set" if self.srctree is None else
                 'srctree "{}"'.format(self.srctree),
             'config symbol prefix "{}"'.format(self.config_prefix),
-            "warnings " + ("enabled" if self._warnings_enabled else "disabled"),
+            "warnings " +
+                ("enabled" if self._warnings_enabled else "disabled"),
+            "printing of warnings to stderr " +
+                ("enabled" if self._warn_to_stderr else "disabled"),
             "undef. symbol assignment warnings " +
                 ("enabled" if self._warn_for_undef_assign else "disabled"),
             "redundant symbol assignment warnings " +
@@ -2536,7 +2580,13 @@ class Kconfig(object):
         # For printing general warnings
 
         if self._warnings_enabled:
-            _stderr_msg("warning: " + msg, filename, linenr)
+            msg = "warning: " + msg
+            if filename is not None:
+                msg = "{}:{}: {}".format(filename, linenr, msg)
+
+            self.warnings.append(msg)
+            if self._warn_to_stderr:
+                sys.stderr.write(msg + "\n")
 
     def _warn_undef_assign(self, msg, filename=None, linenr=None):
         # See the class documentation
@@ -4340,12 +4390,6 @@ def _sym_to_num(sym):
     return sym.tri_value if sym.orig_type in (BOOL, TRISTATE) else \
            int(sym.str_value, _TYPE_TO_BASE[sym.orig_type])
 
-def _stderr_msg(msg, filename, linenr):
-    if filename is not None:
-        msg = "{}:{}: {}".format(filename, linenr, msg)
-
-    sys.stderr.write(msg + "\n")
-
 def _internal_error(msg):
     raise InternalError(
         msg +
diff --git a/testsuite.py b/testsuite.py
index 9a2f1fc..fbc511b 100644
--- a/testsuite.py
+++ b/testsuite.py
@@ -728,7 +728,7 @@ choice
     print("Testing Kconfig.__repr__()")
 
     verify_repr(c, """
-<configuration with 15 symbols, main menu prompt "Linux Kernel Configuration", srctree not set, config symbol prefix "CONFIG_", warnings disabled, undef. symbol assignment warnings disabled, redundant symbol assignment warnings enabled>
+<configuration with 15 symbols, main menu prompt "Linux Kernel Configuration", srctree not set, config symbol prefix "CONFIG_", warnings disabled, printing of warnings to stderr enabled, undef. symbol assignment warnings disabled, redundant symbol assignment warnings enabled>
 """)
 
     os.environ["srctree"] = "srctree value"
@@ -736,11 +736,12 @@ choice
 
     c = Kconfig("Kconfiglib/tests/Krepr", warn=False)
     c.enable_warnings()
+    c.disable_stderr_warnings()
     c.disable_redun_warnings()
     c.enable_undef_warnings()
 
     verify_repr(c, """
-<configuration with 15 symbols, main menu prompt "Linux Kernel Configuration", srctree "srctree value", config symbol prefix "CONFIG_ value", warnings enabled, undef. symbol assignment warnings enabled, redundant symbol assignment warnings disabled>
+<configuration with 15 symbols, main menu prompt "Linux Kernel Configuration", srctree "srctree value", config symbol prefix "CONFIG_ value", warnings enabled, printing of warnings to stderr disabled, undef. symbol assignment warnings enabled, redundant symbol assignment warnings disabled>
 """)
 
     os.environ.pop("srctree", None)
@@ -1908,6 +1909,8 @@ def test_sanity(conf, arch, srcarch):
     conf.disable_undef_warnings()
     conf.enable_warnings()
     conf.disable_warnings()
+    conf.enable_stderr_warnings()
+    conf.disable_stderr_warnings()
     conf.mainmenu_text
     conf.unset_values()