Merge "Use python3 specifically for envsetup.sh"
diff --git a/core/dex_preopt_libart.mk b/core/dex_preopt_libart.mk
index 8f0702b..393053d 100644
--- a/core/dex_preopt_libart.mk
+++ b/core/dex_preopt_libart.mk
@@ -68,7 +68,7 @@
   endif
   LOCAL_MODULE_CLASS := ETC
   include $(BUILD_PREBUILT)
-  $(LOCAL_BUILT_MODULE): $(my_unstripped_installed)
+  $(LOCAL_BUILT_MODULE): | $(my_unstripped_installed)
   # Installing boot.art causes all boot image bits to be installed.
   # Keep this old behavior in case anyone still needs it.
   $(LOCAL_INSTALLED_MODULE): $(my_installed)
diff --git a/core/dynamic_binary.mk b/core/dynamic_binary.mk
index 48072b3..5120e7e 100644
--- a/core/dynamic_binary.mk
+++ b/core/dynamic_binary.mk
@@ -87,9 +87,14 @@
 ###########################################################
 ## Strip
 ###########################################################
-strip_input := $(symbolic_output)
+strip_input := $(inject_module)
 strip_output := $(LOCAL_BUILT_MODULE)
 
+# Use an order-only dependency to ensure the unstripped file in the symbols
+# directory is copied when the module is built, but does not force the
+# module to be rebuilt when the symbols directory is cleaned by installclean.
+$(strip_output): | $(symbolic_output)
+
 my_strip_module := $(firstword \
   $(LOCAL_STRIP_MODULE_$($(my_prefix)$(LOCAL_2ND_ARCH_VAR_PREFIX)ARCH)) \
   $(LOCAL_STRIP_MODULE))
diff --git a/core/soong_app_prebuilt.mk b/core/soong_app_prebuilt.mk
index b7c21b8..82fb413 100644
--- a/core/soong_app_prebuilt.mk
+++ b/core/soong_app_prebuilt.mk
@@ -147,7 +147,7 @@
 # install symbol files of JNI libraries
 my_jni_lib_symbols_copy_files := $(foreach f,$(LOCAL_SOONG_JNI_LIBS_SYMBOLS),\
   $(call word-colon,1,$(f)):$(patsubst $(PRODUCT_OUT)/%,$(TARGET_OUT_UNSTRIPPED)/%,$(call word-colon,2,$(f))))
-$(LOCAL_BUILT_MODULE): $(call copy-many-files, $(my_jni_lib_symbols_copy_files))
+$(LOCAL_BUILT_MODULE): | $(call copy-many-files, $(my_jni_lib_symbols_copy_files))
 
 # embedded JNI will already have been handled by soong
 my_embed_jni :=
diff --git a/core/soong_cc_prebuilt.mk b/core/soong_cc_prebuilt.mk
index a12ef66..4d7b614 100644
--- a/core/soong_cc_prebuilt.mk
+++ b/core/soong_cc_prebuilt.mk
@@ -170,7 +170,7 @@
       my_unstripped_path := $(patsubst $(TARGET_OUT_UNSTRIPPED)/root/%,$(TARGET_OUT_UNSTRIPPED)/%, $(my_unstripped_path))
       symbolic_output := $(my_unstripped_path)/$(my_installed_module_stem)
       $(eval $(call copy-one-file,$(LOCAL_SOONG_UNSTRIPPED_BINARY),$(symbolic_output)))
-      $(call add-dependency,$(LOCAL_BUILT_MODULE),$(symbolic_output))
+      $(LOCAL_BUILT_MODULE): | $(symbolic_output)
 
       ifeq ($(BREAKPAD_GENERATE_SYMBOLS),true)
         my_breakpad_path := $(TARGET_OUT_BREAKPAD)/$(patsubst $(PRODUCT_OUT)/%,%,$(my_symbol_path))
diff --git a/core/soong_rust_prebuilt.mk b/core/soong_rust_prebuilt.mk
index c382f6a..26c099b 100644
--- a/core/soong_rust_prebuilt.mk
+++ b/core/soong_rust_prebuilt.mk
@@ -119,7 +119,7 @@
     my_unstripped_path := $(patsubst $(TARGET_OUT_UNSTRIPPED)/root/%,$(TARGET_OUT_UNSTRIPPED)/%, $(my_unstripped_path))
     symbolic_output := $(my_unstripped_path)/$(my_installed_module_stem)
     $(eval $(call copy-one-file,$(LOCAL_SOONG_UNSTRIPPED_BINARY),$(symbolic_output)))
-    $(call add-dependency,$(LOCAL_BUILT_MODULE),$(symbolic_output))
+    $(LOCAL_BUILT_MODULE): | $(symbolic_output)
   endif
 endif
 
diff --git a/tools/releasetools/common.py b/tools/releasetools/common.py
index 83425cc..b397fd0 100644
--- a/tools/releasetools/common.py
+++ b/tools/releasetools/common.py
@@ -138,6 +138,7 @@
 # existing search paths.
 RAMDISK_BUILD_PROP_REL_PATHS = ['system/etc/ramdisk/build.prop']
 
+
 class ErrorCode(object):
   """Define error_codes for failures that happen during the actual
   update package installation.
@@ -226,6 +227,7 @@
 def SetHostToolLocation(tool_name, location):
   OPTIONS.host_tools[tool_name] = location
 
+
 def FindHostToolPath(tool_name):
   """Finds the path to the host tool.
 
@@ -246,6 +248,7 @@
 
   return tool_name
 
+
 def Run(args, verbose=None, **kwargs):
   """Creates and returns a subprocess.Popen object.
 
@@ -434,6 +437,13 @@
     return self._fingerprint
 
   @property
+  def is_vabc(self):
+    vendor_prop = self.info_dict.get("vendor.build.prop")
+    vabc_enabled = vendor_prop and \
+        vendor_prop.GetProp("ro.virtual_ab.compression.enabled") == "true"
+    return vabc_enabled
+
+  @property
   def oem_props(self):
     return self._oem_props
 
@@ -461,7 +471,7 @@
     """Returns the inquired build property for the provided partition."""
 
     # Boot image uses ro.[product.]bootimage instead of boot.
-    prop_partition =  "bootimage" if partition == "boot" else partition
+    prop_partition = "bootimage" if partition == "boot" else partition
 
     # If provided a partition for this property, only look within that
     # partition's build.prop.
@@ -652,10 +662,12 @@
       raise KeyError(fn)
     return file
 
+
 class RamdiskFormat(object):
   LZ4 = 1
   GZ = 2
 
+
 def _GetRamdiskFormat(info_dict):
   if info_dict.get('lz4_ramdisks') == 'true':
     ramdisk_format = RamdiskFormat.LZ4
@@ -663,6 +675,7 @@
     ramdisk_format = RamdiskFormat.GZ
   return ramdisk_format
 
+
 def LoadInfoDict(input_file, repacking=False):
   """Loads the key/value pairs from the given input target_files.
 
@@ -781,7 +794,8 @@
     for partition in PARTITIONS_WITH_BUILD_PROP:
       fingerprint = build_info.GetPartitionFingerprint(partition)
       if fingerprint:
-        d["avb_{}_salt".format(partition)] = sha256(fingerprint.encode()).hexdigest()
+        d["avb_{}_salt".format(partition)] = sha256(
+            fingerprint.encode()).hexdigest()
   try:
     d["ab_partitions"] = read_helper("META/ab_partitions.txt").split("\n")
   except KeyError:
@@ -789,7 +803,6 @@
   return d
 
 
-
 def LoadListFromFile(file_path):
   with open(file_path) as f:
     return f.read().splitlines()
@@ -859,7 +872,8 @@
     """Loads the build.prop file and builds the attributes."""
 
     if name == "boot":
-      data = PartitionBuildProps._ReadBootPropFile(input_file, ramdisk_format=ramdisk_format)
+      data = PartitionBuildProps._ReadBootPropFile(
+          input_file, ramdisk_format=ramdisk_format)
     else:
       data = PartitionBuildProps._ReadPartitionPropFile(input_file, name)
 
@@ -1106,7 +1120,7 @@
     return " ".join(sorted(combined))
 
   if (framework_dict.get("use_dynamic_partitions") !=
-      "true") or (vendor_dict.get("use_dynamic_partitions") != "true"):
+          "true") or (vendor_dict.get("use_dynamic_partitions") != "true"):
     raise ValueError("Both dictionaries must have use_dynamic_partitions=true")
 
   merged_dict = {"use_dynamic_partitions": "true"}
@@ -1371,7 +1385,8 @@
 
   # Checks key_path exists, before appending --gki_signing_* args.
   if not os.path.exists(key_path):
-    raise ExternalError('gki_signing_key_path: "{}" not found'.format(key_path))
+    raise ExternalError(
+        'gki_signing_key_path: "{}" not found'.format(key_path))
 
   algorithm = OPTIONS.info_dict.get("gki_signing_algorithm")
   if key_path and algorithm:
@@ -1588,7 +1603,7 @@
   RunAndCheckOutput(cmd)
 
   if (info_dict.get("boot_signer") == "true" and
-      info_dict.get("verity_key")):
+          info_dict.get("verity_key")):
     # Hard-code the path as "/boot" for two-step special recovery image (which
     # will be loaded into /boot during the two-step OTA).
     if two_step_image:
@@ -1753,14 +1768,17 @@
   if os.access(fn, os.F_OK):
     ramdisk_fragments = shlex.split(open(fn).read().rstrip("\n"))
     for ramdisk_fragment in ramdisk_fragments:
-      fn = os.path.join(sourcedir, "RAMDISK_FRAGMENTS", ramdisk_fragment, "mkbootimg_args")
+      fn = os.path.join(sourcedir, "RAMDISK_FRAGMENTS",
+                        ramdisk_fragment, "mkbootimg_args")
       cmd.extend(shlex.split(open(fn).read().rstrip("\n")))
-      fn = os.path.join(sourcedir, "RAMDISK_FRAGMENTS", ramdisk_fragment, "prebuilt_ramdisk")
+      fn = os.path.join(sourcedir, "RAMDISK_FRAGMENTS",
+                        ramdisk_fragment, "prebuilt_ramdisk")
       # Use prebuilt image if found, else create ramdisk from supplied files.
       if os.access(fn, os.F_OK):
         ramdisk_fragment_pathname = fn
       else:
-        ramdisk_fragment_root = os.path.join(sourcedir, "RAMDISK_FRAGMENTS", ramdisk_fragment)
+        ramdisk_fragment_root = os.path.join(
+            sourcedir, "RAMDISK_FRAGMENTS", ramdisk_fragment)
         ramdisk_fragment_img = _MakeRamdisk(ramdisk_fragment_root,
                                             ramdisk_format=ramdisk_format)
         ramdisk_fragment_imgs.append(ramdisk_fragment_img)
@@ -3533,7 +3551,7 @@
 
     for g in tgt_groups:
       for p in shlex.split(info_dict.get(
-          "super_%s_partition_list" % g, "").strip()):
+              "super_%s_partition_list" % g, "").strip()):
         assert p in self._partition_updates, \
             "{} is in target super_{}_partition_list but no BlockDifference " \
             "object is provided.".format(p, g)
@@ -3541,7 +3559,7 @@
 
     for g in src_groups:
       for p in shlex.split(source_info_dict.get(
-          "super_%s_partition_list" % g, "").strip()):
+              "super_%s_partition_list" % g, "").strip()):
         assert p in self._partition_updates, \
             "{} is in source super_{}_partition_list but no BlockDifference " \
             "object is provided.".format(p, g)
@@ -3650,7 +3668,7 @@
       if u.src_size is not None and u.tgt_size is None:
         append('remove_group %s' % g)
       if (u.src_size is not None and u.tgt_size is not None and
-          u.src_size > u.tgt_size):
+              u.src_size > u.tgt_size):
         comment('Shrink group %s from %d to %d' % (g, u.src_size, u.tgt_size))
         append('resize_group %s %d' % (g, u.tgt_size))
 
@@ -3659,7 +3677,7 @@
         comment('Add group %s with maximum size %d' % (g, u.tgt_size))
         append('add_group %s %d' % (g, u.tgt_size))
       if (u.src_size is not None and u.tgt_size is not None and
-          u.src_size < u.tgt_size):
+              u.src_size < u.tgt_size):
         comment('Grow group %s from %d to %d' % (g, u.src_size, u.tgt_size))
         append('resize_group %s %d' % (g, u.tgt_size))
 
@@ -3693,7 +3711,8 @@
   """
   tmp_dir = MakeTempDir('boot_', suffix='.img')
   try:
-    RunAndCheckOutput(['unpack_bootimg', '--boot_img', boot_img, '--out', tmp_dir])
+    RunAndCheckOutput(['unpack_bootimg', '--boot_img',
+                      boot_img, '--out', tmp_dir])
     ramdisk = os.path.join(tmp_dir, 'ramdisk')
     if not os.path.isfile(ramdisk):
       logger.warning('Unable to get boot image timestamp: no ramdisk in boot')
@@ -3704,7 +3723,8 @@
     elif ramdisk_format == RamdiskFormat.GZ:
       with open(ramdisk, 'rb') as input_stream:
         with open(uncompressed_ramdisk, 'wb') as output_stream:
-          p2 = Run(['minigzip', '-d'], stdin=input_stream.fileno(), stdout=output_stream.fileno())
+          p2 = Run(['minigzip', '-d'], stdin=input_stream.fileno(),
+                   stdout=output_stream.fileno())
           p2.wait()
     else:
       logger.error('Only support lz4 or minigzip ramdisk format.')
@@ -3715,13 +3735,14 @@
     # Use "toybox cpio" instead of "cpio" because the latter invokes cpio from
     # the host environment.
     RunAndCheckOutput(['toybox', 'cpio', '-F', abs_uncompressed_ramdisk, '-i'],
-               cwd=extracted_ramdisk)
+                      cwd=extracted_ramdisk)
 
     for search_path in RAMDISK_BUILD_PROP_REL_PATHS:
       prop_file = os.path.join(extracted_ramdisk, search_path)
       if os.path.isfile(prop_file):
         return prop_file
-      logger.warning('Unable to get boot image timestamp: no %s in ramdisk', search_path)
+      logger.warning(
+          'Unable to get boot image timestamp: no %s in ramdisk', search_path)
 
     return None
 
@@ -3754,7 +3775,8 @@
     timestamp = props.GetProp('ro.bootimage.build.date.utc')
     if timestamp:
       return int(timestamp)
-    logger.warning('Unable to get boot image timestamp: ro.bootimage.build.date.utc is undefined')
+    logger.warning(
+        'Unable to get boot image timestamp: ro.bootimage.build.date.utc is undefined')
     return None
 
   except ExternalError as e:
diff --git a/tools/releasetools/ota_from_target_files.py b/tools/releasetools/ota_from_target_files.py
index 02b2b4d..abbcfa0 100755
--- a/tools/releasetools/ota_from_target_files.py
+++ b/tools/releasetools/ota_from_target_files.py
@@ -1051,15 +1051,18 @@
         "META/ab_partitions.txt is required for ab_update."
     target_info = common.BuildInfo(OPTIONS.target_info_dict, OPTIONS.oem_dicts)
     source_info = common.BuildInfo(OPTIONS.source_info_dict, OPTIONS.oem_dicts)
-    vendor_prop = source_info.info_dict.get("vendor.build.prop")
-    vabc_used = vendor_prop and \
-        vendor_prop.GetProp("ro.virtual_ab.compression.enabled") == "true" and \
-        not OPTIONS.disable_vabc
-    if vabc_used:
+    # If source supports VABC, delta_generator/update_engine will attempt to
+    # use VABC. This dangerous, as the target build won't have snapuserd to
+    # serve I/O request when device boots. Therefore, disable VABC if source
+    # build doesn't supports it.
+    if not source_info.is_vabc or not target_info.is_vabc:
+      OPTIONS.disable_vabc = True
+    if not OPTIONS.disable_vabc:
       # TODO(zhangkelvin) Remove this once FEC on VABC is supported
       logger.info("Virtual AB Compression enabled, disabling FEC")
       OPTIONS.disable_fec_computation = True
       OPTIONS.disable_verity_computation = True
+
   else:
     assert "ab_partitions" in OPTIONS.info_dict, \
         "META/ab_partitions.txt is required for ab_update."
diff --git a/tools/warn.py b/tools/warn.py
index 5f796f5..97f54f9 100755
--- a/tools/warn.py
+++ b/tools/warn.py
@@ -27,6 +27,7 @@
 
 
 def main():
+  """Old main() calls warn.warn."""
   os.environ['PYTHONPATH'] = os.path.dirname(os.path.abspath(__file__))
   subprocess.check_call(['/usr/bin/python3', '-m', 'warn.warn'] + sys.argv[1:])
 
diff --git a/tools/warn/android_project_list.py b/tools/warn/android_project_list.py
index 82c0fbd..8383dc0 100644
--- a/tools/warn/android_project_list.py
+++ b/tools/warn/android_project_list.py
@@ -17,6 +17,7 @@
 
 
 def create_pattern(name, pattern=None):
+  """Return a tuple of name and warn patten."""
   if pattern is not None:
     return [name, '(^|.*/)' + pattern + '/.*: warning:']
   return [name, '(^|.*/)' + name + '/.*: warning:']
diff --git a/tools/warn/chrome_project_list.py b/tools/warn/chrome_project_list.py
index 6096522..d8b2179 100644
--- a/tools/warn/chrome_project_list.py
+++ b/tools/warn/chrome_project_list.py
@@ -8,6 +8,7 @@
 
 
 def create_pattern(pattern):
+  """Return a tuple of name and warn patten."""
   return [pattern, '(^|.*/)' + pattern + '/.*: warning:']
 
 
diff --git a/tools/warn/cpp_warn_patterns.py b/tools/warn/cpp_warn_patterns.py
index e8783bc..2fa9916 100644
--- a/tools/warn/cpp_warn_patterns.py
+++ b/tools/warn/cpp_warn_patterns.py
@@ -15,10 +15,12 @@
 
 """Warning patterns for C/C++ compiler, but not clang-tidy."""
 
+# No need of doc strings for trivial small functions.
+# pylint:disable=missing-function-docstring
+
 import re
 
 # pylint:disable=relative-beyond-top-level
-# pylint:disable=g-importing-member
 from .severity import Severity
 
 
@@ -56,7 +58,8 @@
 
 
 warn_patterns = [
-    # pylint:disable=line-too-long,g-inconsistent-quotes
+    # pylint does not recognize g-inconsistent-quotes
+    # pylint:disable=line-too-long,bad-option-value,g-inconsistent-quotes
     medium('Implicit function declaration',
            [r".*: warning: implicit declaration of function .+",
             r".*: warning: implicitly declaring library function"]),
@@ -300,7 +303,7 @@
     medium('Missing noreturn',
            [r".*: warning: function '.*' could be declared with attribute 'noreturn'"]),
     medium('User warning',
-           [r".*: warning: #warning "".+"""]),
+           [r".*: warning: #warning \".+\""]),
     medium('Vexing parsing problem',
            [r".*: warning: empty parentheses interpreted as a function declaration"]),
     medium('Dereferencing void*',
diff --git a/tools/warn/html_writer.py b/tools/warn/html_writer.py
index be71b55..bed25ed 100644
--- a/tools/warn/html_writer.py
+++ b/tools/warn/html_writer.py
@@ -15,6 +15,9 @@
 
 """Emit warning messages to html or csv files."""
 
+# Many functions in this module have too many arguments to be refactored.
+# pylint:disable=too-many-arguments,missing-function-docstring
+
 # To emit html page of warning messages:
 #   flags: --byproject, --url, --separator
 # Old stuff for static html components:
@@ -57,11 +60,10 @@
 import sys
 
 # pylint:disable=relative-beyond-top-level
-# pylint:disable=g-importing-member
 from .severity import Severity
 
 
-html_head_scripts = """\
+HTML_HEAD_SCRIPTS = """\
   <script type="text/javascript">
   function expand(id) {
     var e = document.getElementById(id);
@@ -113,7 +115,7 @@
 def dump_html_prologue(title, writer, warn_patterns, project_names):
   writer('<html>\n<head>')
   writer('<title>' + title + '</title>')
-  writer(html_head_scripts)
+  writer(HTML_HEAD_SCRIPTS)
   emit_stats_by_project(writer, warn_patterns, project_names)
   writer('</head>\n<body>')
   writer(html_big(title))
@@ -142,7 +144,7 @@
     2D warnings array where warnings[p][s] is # of warnings in project name p of
     severity level s
   """
-  # pylint:disable=g-complex-comprehension
+  # pylint:disable=invalid-name
   warnings = {p: {s.value: 0 for s in Severity.levels} for p in project_names}
   for i in warn_patterns:
     s = i['severity'].value
@@ -153,7 +155,6 @@
 
 def get_total_by_project(warnings, project_names):
   """Returns dict, project as key and # warnings for that project as value."""
-  # pylint:disable=g-complex-comprehension
   return {
       p: sum(warnings[p][s.value] for s in Severity.levels)
       for p in project_names
@@ -162,7 +163,6 @@
 
 def get_total_by_severity(warnings, project_names):
   """Returns dict, severity as key and # warnings of that severity as value."""
-  # pylint:disable=g-complex-comprehension
   return {
       s.value: sum(warnings[p][s.value] for p in project_names)
       for s in Severity.levels
@@ -235,7 +235,7 @@
   writer('<script>')
   emit_const_string_array('StatsHeader', stats_header, writer)
   emit_const_object_array('StatsRows', stats_rows, writer)
-  writer(draw_table_javascript)
+  writer(DRAW_TABLE_JAVASCRIPT)
   writer('</script>')
 
 
@@ -246,8 +246,8 @@
   total_by_project = get_total_by_project(warnings, project_names)
   total_by_severity = get_total_by_severity(warnings, project_names)
   stats_header = emit_table_header(total_by_severity)
-  total_all_projects, stats_rows = \
-    emit_row_counts_per_project(warnings, total_by_project, total_by_severity, project_names)
+  total_all_projects, stats_rows = emit_row_counts_per_project(
+      warnings, total_by_project, total_by_severity, project_names)
   emit_row_counts_per_severity(total_by_severity, stats_header, stats_rows,
                                total_all_projects, writer)
 
@@ -287,6 +287,7 @@
 #     id for each warning pattern
 #     sort by project, severity, warn_id, warning_message
 def emit_buttons(writer):
+  """Write the button elements in HTML."""
   writer('<button class="button" onclick="expandCollapse(1);">'
          'Expand all warnings</button>\n'
          '<button class="button" onclick="expandCollapse(0);">'
@@ -412,7 +413,7 @@
   writer('];')
 
 
-scripts_for_warning_groups = """
+SCRIPTS_FOR_WARNING_GROUPS = """
   function compareMessages(x1, x2) { // of the same warning type
     return (WarningMessages[x1[2]] <= WarningMessages[x2[2]]) ? -1 : 1;
   }
@@ -620,7 +621,7 @@
     emit_const_html_string_array('WarningLinks', warning_links, writer)
 
 
-draw_table_javascript = """
+DRAW_TABLE_JAVASCRIPT = """
 google.charts.load('current', {'packages':['table']});
 google.charts.setOnLoadCallback(drawTable);
 function drawTable() {
@@ -653,7 +654,7 @@
   writer('\n<script>')
   emit_js_data(writer, flags, warning_messages, warning_links, warning_records,
                warn_patterns, project_names)
-  writer(scripts_for_warning_groups)
+  writer(SCRIPTS_FOR_WARNING_GROUPS)
   writer('</script>')
   emit_buttons(writer)
   # Warning messages are grouped by severities or project names.
diff --git a/tools/warn/java_warn_patterns.py b/tools/warn/java_warn_patterns.py
index ac1ed5d..534f48d 100644
--- a/tools/warn/java_warn_patterns.py
+++ b/tools/warn/java_warn_patterns.py
@@ -15,8 +15,10 @@
 
 """Warning patterns for Java compiler tools."""
 
+# No need of doc strings for trivial small functions.
+# pylint:disable=missing-function-docstring
+
 # pylint:disable=relative-beyond-top-level
-# pylint:disable=g-importing-member
 from .cpp_warn_patterns import compile_patterns
 from .severity import Severity
 
@@ -59,7 +61,8 @@
 
 
 warn_patterns = [
-    # pylint:disable=line-too-long,g-inconsistent-quotes
+    # pylint does not recognize g-inconsistent-quotes
+    # pylint:disable=line-too-long,bad-option-value,g-inconsistent-quotes
     # Warnings from Javac
     java_medium('Use of deprecated',
                 [r'.*: warning: \[deprecation\] .+',
diff --git a/tools/warn/make_warn_patterns.py b/tools/warn/make_warn_patterns.py
index 4b20493..a54c502 100644
--- a/tools/warn/make_warn_patterns.py
+++ b/tools/warn/make_warn_patterns.py
@@ -16,12 +16,12 @@
 """Warning patterns for build make tools."""
 
 # pylint:disable=relative-beyond-top-level
-# pylint:disable=g-importing-member
 from .cpp_warn_patterns import compile_patterns
 from .severity import Severity
 
 warn_patterns = [
-    # pylint:disable=line-too-long,g-inconsistent-quotes
+    # pylint does not recognize g-inconsistent-quotes
+    # pylint:disable=line-too-long,bad-option-value,g-inconsistent-quotes
     {'category': 'make', 'severity': Severity.MEDIUM,
      'description': 'make: overriding commands/ignoring old commands',
      'patterns': [r".*: warning: overriding commands for target .+",
diff --git a/tools/warn/other_warn_patterns.py b/tools/warn/other_warn_patterns.py
index 8df5b87..d05c8e9 100644
--- a/tools/warn/other_warn_patterns.py
+++ b/tools/warn/other_warn_patterns.py
@@ -15,8 +15,10 @@
 
 """Warning patterns from other tools."""
 
+# No need of doc strings for trivial small functions.
+# pylint:disable=missing-function-docstring
+
 # pylint:disable=relative-beyond-top-level
-# pylint:disable=g-importing-member
 from .cpp_warn_patterns import compile_patterns
 from .severity import Severity
 
@@ -57,7 +59,8 @@
 
 
 warn_patterns = [
-    # pylint:disable=line-too-long,g-inconsistent-quotes
+    # pylint does not recognize g-inconsistent-quotes
+    # pylint:disable=line-too-long,bad-option-value,g-inconsistent-quotes
     # aapt warnings
     aapt('No comment for public symbol',
          [r".*: warning: No comment for public symbol .+"]),
diff --git a/tools/warn/severity.py b/tools/warn/severity.py
index b4c03c9..20064c3 100644
--- a/tools/warn/severity.py
+++ b/tools/warn/severity.py
@@ -19,8 +19,9 @@
 """
 
 
-# pylint:disable=old-style-class
+# pylint:disable=too-few-public-methods
 class SeverityInfo:
+  """Class of Severity Info, part of a Severity object."""
 
   def __init__(self, value, color, column_header, header):
     self.value = value
@@ -29,7 +30,7 @@
     self.header = header
 
 
-# pylint:disable=old-style-class
+# pylint:disable=too-few-public-methods
 class Severity:
   """Class of Severity levels where each level is a SeverityInfo."""
 
diff --git a/tools/warn/tidy_warn_patterns.py b/tools/warn/tidy_warn_patterns.py
index 5416cb2..7018d10 100644
--- a/tools/warn/tidy_warn_patterns.py
+++ b/tools/warn/tidy_warn_patterns.py
@@ -15,8 +15,10 @@
 
 """Warning patterns for clang-tidy."""
 
+# No need of doc strings for trivial small functions.
+# pylint:disable=missing-function-docstring
+
 # pylint:disable=relative-beyond-top-level
-# pylint:disable=g-importing-member
 from .cpp_warn_patterns import compile_patterns
 from .severity import Severity
 
@@ -39,7 +41,6 @@
 
 
 def analyzer_high(description, patterns):
-  # Important clang analyzer warnings to be fixed ASAP.
   return {
       'category': 'C/C++',
       'severity': Severity.HIGH,
@@ -74,7 +75,8 @@
 
 
 warn_patterns = [
-    # pylint:disable=line-too-long,g-inconsistent-quotes
+    # pylint does not recognize g-inconsistent-quotes
+    # pylint:disable=line-too-long,bad-option-value,g-inconsistent-quotes
     group_tidy_warn_pattern('android'),
     simple_tidy_warn_pattern('abseil-string-find-startswith'),
     simple_tidy_warn_pattern('bugprone-argument-comment'),
diff --git a/tools/warn/warn.py b/tools/warn/warn.py
index cb5daec..acfbb55 100755
--- a/tools/warn/warn.py
+++ b/tools/warn/warn.py
@@ -20,7 +20,8 @@
 import signal
 import sys
 
-# pylint:disable=relative-beyond-top-level
+# pylint:disable=relative-beyond-top-level,no-name-in-module
+# suppress false positive of no-name-in-module warnings
 from . import warn_common as common
 
 
@@ -50,6 +51,7 @@
 
 def create_and_launch_subprocesses(num_cpu, classify_warnings_fn, arg_groups,
                                    group_results):
+  """Fork num_cpu processes to classify warnings."""
   pool = multiprocessing.Pool(num_cpu)
   for cpu in range(num_cpu):
     proc_result = pool.map(classify_warnings_fn, arg_groups[cpu])
@@ -59,6 +61,7 @@
 
 
 def main():
+  """Old main() calls new common_main."""
   use_google3 = False
   common.common_main(use_google3, create_and_launch_subprocesses,
                      classify_warnings)
diff --git a/tools/warn/warn_common.py b/tools/warn/warn_common.py
index b2dd8ab..d69050f 100755
--- a/tools/warn/warn_common.py
+++ b/tools/warn/warn_common.py
@@ -52,8 +52,8 @@
 import re
 import sys
 
-# pylint:disable=relative-beyond-top-level
-# pylint:disable=g-importing-member
+# pylint:disable=relative-beyond-top-level,no-name-in-module
+# suppress false positive of no-name-in-module warnings
 from . import android_project_list
 from . import chrome_project_list
 from . import cpp_warn_patterns as cpp_patterns
@@ -115,6 +115,8 @@
 
 
 def find_project_index(line, project_patterns):
+  """Return the index to the project pattern array."""
+  # pylint:disable=invalid-name
   for i, p in enumerate(project_patterns):
     if p.match(line):
       return i
@@ -124,30 +126,30 @@
 def classify_one_warning(warning, link, results, project_patterns,
                          warn_patterns):
   """Classify one warning line."""
+  # pylint:disable=invalid-name
   for i, w in enumerate(warn_patterns):
     for cpat in w['compiled_patterns']:
       if cpat.match(warning):
         p = find_project_index(warning, project_patterns)
         results.append([warning, link, i, p])
         return
-      else:
-        # If we end up here, there was a problem parsing the log
-        # probably caused by 'make -j' mixing the output from
-        # 2 or more concurrent compiles
-        pass
+  # If we end up here, there was a problem parsing the log
+  # probably caused by 'make -j' mixing the output from
+  # 2 or more concurrent compiles
 
 
-def remove_prefix(s, sub):
-  """Remove everything before last occurrence of substring sub in string s."""
-  if sub in s:
-    inc_sub = s.rfind(sub)
-    return s[inc_sub:]
-  return s
+def remove_prefix(src, sub):
+  """Remove everything before last occurrence of substring sub in string src."""
+  if sub in src:
+    inc_sub = src.rfind(sub)
+    return src[inc_sub:]
+  return src
 
 
 # TODO(emmavukelj): Don't have any generate_*_cs_link functions call
 # normalize_path a second time (the first time being in parse_input_file)
 def generate_cs_link(warning_line, flags, android_root=None):
+  """Try to add code search HTTP URL prefix."""
   if flags.platform == 'chrome':
     return generate_chrome_cs_link(warning_line, flags)
   if flags.platform == 'android':
@@ -279,8 +281,7 @@
   if idx >= 0:
     # remove chrome_root/, we want path relative to that
     return path[idx + len('chrome_root/'):]
-  else:
-    return path
+  return path
 
 
 def normalize_warning_line(line, flags, android_root=None):
@@ -309,6 +310,7 @@
   # Remove the duplicated warnings save ~8% of time when parsing
   # one typical build log than before
   unique_warnings = dict()
+  # pylint:disable=invalid-name
   for line in infile:
     if warning_pattern.match(line):
       normalized_line = normalize_warning_line(line, flags)
@@ -344,6 +346,7 @@
 
 def parse_input_file_android(infile, flags):
   """Parse Android input file, collect parameters and warning lines."""
+  # pylint:disable=too-many-locals,too-many-branches
   platform_version = 'unknown'
   target_product = 'unknown'
   target_variant = 'unknown'
@@ -393,6 +396,7 @@
             line, flags, android_root, unique_warnings)
       continue
 
+    # pylint:disable=invalid-name
     if line_counter < 100:
       # save a little bit of time by only doing this for the first few lines
       line_counter += 1
@@ -424,6 +428,7 @@
 
 
 def parse_input_file(infile, flags):
+  """Parse one input file for chrome or android."""
   if flags.platform == 'chrome':
     return parse_input_file_chrome(infile, flags)
   if flags.platform == 'android':
@@ -448,9 +453,12 @@
   if platform == 'chrome':
     warn_patterns = cpp_patterns.warn_patterns
   elif platform == 'android':
-    warn_patterns = make_patterns.warn_patterns + cpp_patterns.warn_patterns + java_patterns.warn_patterns + tidy_patterns.warn_patterns + other_patterns.warn_patterns
+    warn_patterns = (make_patterns.warn_patterns + cpp_patterns.warn_patterns +
+                     java_patterns.warn_patterns + tidy_patterns.warn_patterns +
+                     other_patterns.warn_patterns)
   else:
     raise Exception('platform name %s is not valid' % platform)
+  # pylint:disable=invalid-name
   for w in warn_patterns:
     w['members'] = []
     # Each warning pattern has a 'projects' dictionary, that
@@ -473,6 +481,7 @@
                                use_google3, create_launch_subprocs_fn,
                                classify_warnings_fn):
   """Classify all warning lines with num_cpu parallel processes."""
+  # pylint:disable=too-many-arguments,too-many-locals
   num_cpu = args.processes
   group_results = []
 
@@ -531,8 +540,10 @@
 def process_log(logfile, flags, project_names, project_patterns, warn_patterns,
                 html_path, use_google3, create_launch_subprocs_fn,
                 classify_warnings_fn, logfile_object):
-  # pylint: disable=g-doc-args
-  # pylint: disable=g-doc-return-or-yield
+  # pylint does not recognize g-doc-*
+  # pylint: disable=bad-option-value,g-doc-args
+  # pylint: disable=bad-option-value,g-doc-return-or-yield
+  # pylint: disable=too-many-arguments,too-many-locals
   """Function that handles processing of a log.
 
   This is isolated into its own function (rather than just taking place in main)