From c283467009b14d22fdeb466a160b7d4db7fa0c4d Mon Sep 17 00:00:00 2001
From: claireyywang <clairewang@openrobotics.org>
Date: Tue, 28 Jan 2020 15:10:04 -0800
Subject: [PATCH 1/7] update doctor warn

Signed-off-by: claireyywang <clairewang@openrobotics.org>
---
 ros2doctor/ros2doctor/api/__init__.py | 12 ++++++------
 ros2doctor/ros2doctor/api/platform.py | 10 +++++-----
 ros2doctor/ros2doctor/api/topic.py    |  4 ++--
 3 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/ros2doctor/ros2doctor/api/__init__.py b/ros2doctor/ros2doctor/api/__init__.py
index abb4da992..d5ddab64e 100644
--- a/ros2doctor/ros2doctor/api/__init__.py
+++ b/ros2doctor/ros2doctor/api/__init__.py
@@ -94,11 +94,11 @@ def run_checks(*, include_warnings=False) -> Tuple[Set[str], int, int]:
         try:
             check_class = check_entry_pt.load()
         except (ImportError, UnknownExtra):
-            doctor_warn('Check entry point %s fails to load.' % check_entry_pt.name)
+            doctor_warn(f'Check entry point {check_entry_pt.name} fails to load.')
         try:
             check_instance = check_class()
         except Exception:
-            doctor_warn('Unable to instantiate check object from %s.' % check_entry_pt.name)
+            doctor_warn(f'Unable to instantiate check object from {check_entry_pt.name}.')
         try:
             check_category = check_instance.category()
             result = check_instance.check()
@@ -107,7 +107,7 @@ def run_checks(*, include_warnings=False) -> Tuple[Set[str], int, int]:
                 failed_cats.add(check_category)
             total += 1
         except Exception:
-            doctor_warn('Fail to call %s class functions.' % check_entry_pt.name)
+            doctor_warn(f'Fail to call {check_entry_pt.name} class functions.')
     return failed_cats, fail, total
 
 
@@ -122,11 +122,11 @@ def generate_reports(*, categories=None) -> List[Report]:
         try:
             report_class = report_entry_pt.load()
         except (ImportError, UnknownExtra):
-            doctor_warn('Report entry point %s fails to load.' % report_entry_pt.name)
+            doctor_warn(f'Report entry point {report_entry_pt.name} fails to load.')
         try:
             report_instance = report_class()
         except Exception:
-            doctor_warn('Unable to instantiate report object from %s.' % report_entry_pt.name)
+            doctor_warn(f'Unable to instantiate report object from {report_entry_pt.name}.')
         try:
             report_category = report_instance.category()
             report = report_instance.report()
@@ -136,5 +136,5 @@ def generate_reports(*, categories=None) -> List[Report]:
             else:
                 reports.append(report)
         except Exception:
-            doctor_warn('Fail to call %s class functions.' % report_entry_pt.name)
+            doctor_warn(f'Fail to call {report_entry_pt.name} class functions.')
     return reports
diff --git a/ros2doctor/ros2doctor/api/platform.py b/ros2doctor/ros2doctor/api/platform.py
index cee6ea35c..02d2c3634 100644
--- a/ros2doctor/ros2doctor/api/platform.py
+++ b/ros2doctor/ros2doctor/api/platform.py
@@ -44,7 +44,7 @@ def _check_platform_helper() -> Tuple[str, dict, dict]:
     i = rosdistro.get_index(u)
     distro_info = i.distributions.get(distro_name)
     if not distro_info:
-        doctor_warn("Distribution name '%s' is not found" % distro_name)
+        doctor_warn(f"Distribution name {distro_name} is not found")
         return
     distro_data = rosdistro.get_distribution(i, distro_name).get_data()
     return distro_name, distro_info, distro_data
@@ -67,13 +67,13 @@ def check(self):
 
         # check distro status
         if distro_info.get('distribution_status') == 'prerelease':
-            result.add_warning('Distribution %s is not fully supported or tested. '
+            result.add_warning(f'Distribution {distro_name} is not fully supported or tested. '
                                'To get more consistent features, download a stable version at '
-                               'https://index.ros.org/doc/ros2/Installation/' % distro_name)
+                               'https://index.ros.org/doc/ros2/Installation/')
         elif distro_info.get('distribution_status') == 'end-of-life':
-            result.add_warning('Distribution %s is no longer supported or deprecated. '
+            result.add_warning(f'Distribution {distro_name} is no longer supported or deprecated. '
                                'To get the latest features, download the new versions at '
-                               'https://index.ros.org/doc/ros2/Installation/' % distro_name)
+                               'https://index.ros.org/doc/ros2/Installation/')
         return result
 
 
diff --git a/ros2doctor/ros2doctor/api/topic.py b/ros2doctor/ros2doctor/api/topic.py
index ccc2255d6..bf899e4af 100644
--- a/ros2doctor/ros2doctor/api/topic.py
+++ b/ros2doctor/ros2doctor/api/topic.py
@@ -49,9 +49,9 @@ def check(self):
                 pub_count = node.count_publishers(topic)
                 sub_count = node.count_subscribers(topic)
                 if pub_count > sub_count:
-                    result.add_warning('Publisher without subscriber detected on %s.' % topic)
+                    result.add_warning(f'Publisher without subscriber detected on {topic}.')
                 elif pub_count < sub_count:
-                    result.add_warning('Subscriber without publisher detected on %s.' % topic)
+                    result.add_warning(f'Subscriber without publisher detected on {topic}.')
         return result
 
 

From cfb719719fac368a4bef4c82da23f39cbec17c35 Mon Sep 17 00:00:00 2001
From: claireyywang <clairewang@openrobotics.org>
Date: Wed, 29 Jan 2020 16:32:50 -0800
Subject: [PATCH 2/7] decouple warning/error msg from result to show traceback

Signed-off-by: claireyywang <clairewang@openrobotics.org>
---
 ros2doctor/ros2doctor/api/__init__.py   | 18 ++++---
 ros2doctor/ros2doctor/api/format.py     | 35 ++++----------
 ros2doctor/ros2doctor/api/network.py    | 26 +++++++----
 ros2doctor/ros2doctor/api/package.py    | 62 +++++++++++++++++--------
 ros2doctor/ros2doctor/api/platform.py   | 27 ++++++-----
 ros2doctor/ros2doctor/api/topic.py      |  8 ++--
 ros2doctor/ros2doctor/command/doctor.py | 10 ++--
 7 files changed, 101 insertions(+), 85 deletions(-)

diff --git a/ros2doctor/ros2doctor/api/__init__.py b/ros2doctor/ros2doctor/api/__init__.py
index d5ddab64e..47b07de1d 100644
--- a/ros2doctor/ros2doctor/api/__init__.py
+++ b/ros2doctor/ros2doctor/api/__init__.py
@@ -71,12 +71,10 @@ def __init__(self):
         self.error = 0
         self.warning = 0
 
-    def add_error(self, msg) -> None:
-        doctor_warn(msg)
+    def add_error(self) -> None:
         self.error += 1
 
-    def add_warning(self, msg) -> None:
-        doctor_warn(msg)
+    def add_warning(self) -> None:
         self.warning += 1
 
 
@@ -94,11 +92,11 @@ def run_checks(*, include_warnings=False) -> Tuple[Set[str], int, int]:
         try:
             check_class = check_entry_pt.load()
         except (ImportError, UnknownExtra):
-            doctor_warn(f'Check entry point {check_entry_pt.name} fails to load.')
+            doctor_warn()(f'Check entry point {check_entry_pt.name} fails to load.', RuntimeWarning)
         try:
             check_instance = check_class()
         except Exception:
-            doctor_warn(f'Unable to instantiate check object from {check_entry_pt.name}.')
+            doctor_warn()(f'Unable to instantiate check object from {check_entry_pt.name}.', RuntimeWarning)
         try:
             check_category = check_instance.category()
             result = check_instance.check()
@@ -107,7 +105,7 @@ def run_checks(*, include_warnings=False) -> Tuple[Set[str], int, int]:
                 failed_cats.add(check_category)
             total += 1
         except Exception:
-            doctor_warn(f'Fail to call {check_entry_pt.name} class functions.')
+            doctor_warn()(f'Fail to call {check_entry_pt.name} class functions.', RuntimeWarning)
     return failed_cats, fail, total
 
 
@@ -122,11 +120,11 @@ def generate_reports(*, categories=None) -> List[Report]:
         try:
             report_class = report_entry_pt.load()
         except (ImportError, UnknownExtra):
-            doctor_warn(f'Report entry point {report_entry_pt.name} fails to load.')
+            doctor_warn()(f'Report entry point {report_entry_pt.name} fails to load.', RuntimeWarning)
         try:
             report_instance = report_class()
         except Exception:
-            doctor_warn(f'Unable to instantiate report object from {report_entry_pt.name}.')
+            doctor_warn()(f'Unable to instantiate report object from {report_entry_pt.name}.', RuntimeWarning)
         try:
             report_category = report_instance.category()
             report = report_instance.report()
@@ -136,5 +134,5 @@ def generate_reports(*, categories=None) -> List[Report]:
             else:
                 reports.append(report)
         except Exception:
-            doctor_warn(f'Fail to call {report_entry_pt.name} class functions.')
+            doctor_warn()(f'Fail to call {report_entry_pt.name} class functions.', RuntimeWarning)
     return reports
diff --git a/ros2doctor/ros2doctor/api/format.py b/ros2doctor/ros2doctor/api/format.py
index dbf984e65..67abd846c 100644
--- a/ros2doctor/ros2doctor/api/format.py
+++ b/ros2doctor/ros2doctor/api/format.py
@@ -24,7 +24,8 @@ def format_print(report):
     :param report: Report object with name and items list
     """
     print('\n ', report.name)
-    padding_num = compute_padding(report.items)
+    if report.items:
+        padding_num = compute_padding(report.items)
     for item_name, item_content in report.items:
         print('{:{padding}}: {}'.format(item_name, item_content, padding=padding_num))
 
@@ -44,33 +45,13 @@ def compute_padding(report_items: List[Tuple[str, str]]) -> int:
     return padding
 
 
-def custom_warning_format(msg, cat, filename, linenum, file=None, line=None):
-    return '%s: %s: %s: %s\n' % (filename, linenum, cat.__name__, msg)
-
-
-class CustomWarningFormat:
-    """Support custom warning format without modifying default format."""
-
-    def __enter__(self):
-        self._default_format = warnings.formatwarning
-        warnings.formatwarning = custom_warning_format
-
-    def __exit__(self, t, v, trb):
-        """
-        Define exit action for context manager.
-
-        :param t: type
-        :param v: value
-        :param trb: traceback
-        """
-        warnings.formatwarning = self._default_format
-
-
-def doctor_warn(msg: str) -> None:
+def doctor_warn() -> None:
     """
-    Use CustomWarningFormat to print customized warning message.
+    Print customized warning message with package and line info.
 
     :param msg: warning message to be printed
     """
-    with CustomWarningFormat():
-        warnings.warn(msg)
+    def custom_warning_format(message, category, filename, lineno, file=None, line=None):
+        return '%s:%s: %s: %s\n' % (filename, lineno, category.__name__, message)
+    warnings.formatwarning = custom_warning_format
+    return warnings.warn
diff --git a/ros2doctor/ros2doctor/api/network.py b/ros2doctor/ros2doctor/api/network.py
index 8c02d117b..c38a5fe6d 100644
--- a/ros2doctor/ros2doctor/api/network.py
+++ b/ros2doctor/ros2doctor/api/network.py
@@ -14,6 +14,7 @@
 
 import os
 from typing import Tuple
+import warnings
 
 from ros2doctor.api import DoctorCheck
 from ros2doctor.api import DoctorReport
@@ -24,8 +25,8 @@
 try:
     import ifcfg
 except ImportError:  # check import error for windows and osx
-    doctor_warn('Failed to import ifcfg. '
-                'Use `python -m pip install ifcfg` to install needed package.')
+    doctor_warn()('Unable to import ifcfg. '
+        'Use `python -m pip install ifcfg` to install needed package.')
 
 
 def _is_unix_like_platform() -> bool:
@@ -62,22 +63,29 @@ def check(self):
         try:
             ifcfg_ifaces = ifcfg.interfaces()
         except NameError:
-            result.add_error('ERROR: ifcfg is not imported. Unable to run network check.')
+            doctor_warn()('ERROR: `ifcfg` module is not imported. '
+                'Unable to run network check.')
+            result.add_error()
             return result
 
         has_loopback, has_non_loopback, has_multicast = _check_network_config_helper(ifcfg_ifaces)
         if not _is_unix_like_platform():
             if not has_loopback and not has_non_loopback:
                 # no flags found, otherwise one of them should be True.
-                print('No flags found. \
-                    Run `ipconfig` on cmd to check network interfaces.')
+                doctor_warn()('ERROR: No flags found. '
+                    'Run `ipconfig` on Windows or '
+                    'install `ifconfig` on Unix to check network interfaces.')
+                result.add_error()
                 return result
         if not has_loopback:
-            result.add_error('ERROR: No loopback IP address is found.')
+            doctor_warn()('ERROR: No loopback IP address is found.')
+            result.add_error()
         if not has_non_loopback:
-            result.add_warning('Only loopback IP address is found.')
+            doctor_warn()('Only loopback IP address is found.')
+            result.add_warning()
         if not has_multicast:
-            result.add_warning('No multicast IP address is found.')
+            doctor_warn()('No multicast IP address is found.')
+            result.add_warning()
         return result
 
 
@@ -93,7 +101,7 @@ def report(self):
         try:
             ifcfg_ifaces = ifcfg.interfaces()
         except NameError:
-            doctor_warn('ifcfg is not imported. Unable to generate network report.')
+            doctor_warn()('ERROR: ifcfg is not imported. Unable to generate network report.')
             return Report('')
 
         network_report = Report('NETWORK CONFIGURATION')
diff --git a/ros2doctor/ros2doctor/api/package.py b/ros2doctor/ros2doctor/api/package.py
index c0c5641dc..a48a29a17 100644
--- a/ros2doctor/ros2doctor/api/package.py
+++ b/ros2doctor/ros2doctor/api/package.py
@@ -14,6 +14,7 @@
 
 import os
 from typing import List
+import textwrap
 from urllib.error import URLError
 
 from ament_index_python import get_packages_with_prefixes
@@ -24,6 +25,7 @@
 from ros2doctor.api import DoctorReport
 from ros2doctor.api import Report
 from ros2doctor.api import Result
+from ros2doctor.api.format import doctor_warn
 
 import rosdistro
 
@@ -35,11 +37,25 @@ def get_distro_package_versions() -> dict:
     :return: dictionary of rosdistro package name and version
     """
     distro_name = os.environ.get('ROS_DISTRO')
+    if not distro_name:
+        doctor_warn()('ERROR: ROS_DISTRO is not set.')
+        return
     distro_name = distro_name.lower()
     url = rosdistro.get_index_url()
+    if not url:
+        doctor_warn()('ERROR: Unable to access ROSDISTRO_INDEX_URL or DEFAULT_INDEX_URL. '
+            'Check network setting to make sure machine is connected to internet.')
+        return
     i = rosdistro.get_index(url)
-    distro_data = rosdistro.get_distribution(i, distro_name).get_data()
+    distro_info = rosdistro.get_distribution(i, distro_name)
+    if not distro_info:
+        doctor_warn()(f'Distribution name {distro_name} is not found')
+        return
+    distro_data = distro_info.get_data()
     repos_info = distro_data.get('repositories')
+    if not repos_info:
+        doctor_warn()('No repository information found.')
+        return
     distro_package_vers = {}
     for _, info in repos_info.items():
         try:
@@ -69,7 +85,7 @@ def get_local_package_versions() -> dict:
     return local_packages
 
 
-def compare_versions(local_packages: dict, distro_packages: dict) -> List:
+def compare_versions(result: Result, local_packages: dict, distro_packages: dict):
     """
     Return warning messages for PackageCheck, and info for PackageReport.
 
@@ -78,7 +94,6 @@ def compare_versions(local_packages: dict, distro_packages: dict) -> List:
     :param: boolean value determines which output to populate, msgs or report
     :return: list of warning messages
     """
-    warning_msgs = []
     missing_req = ''
     missing_local = ''
     for name, local_ver_str in local_packages.items():
@@ -91,14 +106,26 @@ def compare_versions(local_packages: dict, distro_packages: dict) -> List:
         local_ver = version.parse(local_ver_str).base_version
         required_ver = version.parse(required_ver_str).base_version
         if local_ver < required_ver:
-            warning_msgs.append(f'{name} has been updated to a new version.'
-                                f' local: {local_ver} <'
-                                f' required: {required_ver}')
+            doctor_warn()(f'{name} has been updated to a new version.'
+                f' local: {local_ver} <'
+                f' required: {required_ver}')
+            result.add_warning()
     if missing_req:
-        warning_msgs.append('Cannot find required versions of packages:' + missing_req)
+        if len(missing_req) > 100:
+            doctor_warn()('Cannot find required versions of packages: ' +
+                textwrap.shorten(missing_req, width=100) +
+                ' Use `ros2 doctor --report` to see full list.')
+        else:
+            doctor_warn()('Cannot find required versions of packages: ' +
+                missing_req)
     if missing_local:
-        warning_msgs.append('Cannot find local versions of packages:' + missing_local)
-    return warning_msgs
+        if len(missing_local) > 100:
+            doctor_warn()('Cannot find local versions of packages: ' +
+                textwrap.shorten(missing_local, width=100) +
+                ' Use `ros2 doctor --report` to see full list.')
+        else:
+            doctor_warn()('Cannot find local versions of packages: ' +
+                missing_local)
 
 
 class PackageCheck(DoctorCheck):
@@ -110,21 +137,18 @@ def category(self):
     def check(self):
         """Check packages within the directory where command is called."""
         result = Result()
-        try:
-            distro_package_vers = get_distro_package_versions()
-            if not distro_package_vers:
-                result.add_error('ERROR: distro packages info is not found.')
-        except (AttributeError, RuntimeError, URLError):
-            result.add_error('ERROR: Unable to fetch package information from rosdistro.')
+        distro_package_vers = get_distro_package_versions()
+        if not distro_package_vers:
+            doctor_warn()('ERROR: distro packages info is not found.')
+            result.add_error()
         local_package_vers = get_local_package_versions()
         if not local_package_vers:
-            result.add_error('ERROR: local package info is not found.')
+            doctor_warn()('ERROR: local package info is not found.')
+            result.add_error()
         if result.error != 0:
             return result
 
-        warning_msgs = compare_versions(local_package_vers, distro_package_vers)
-        for msg in warning_msgs:
-            result.add_warning(msg)
+        compare_versions(result, local_package_vers, distro_package_vers)
         return result
 
 
diff --git a/ros2doctor/ros2doctor/api/platform.py b/ros2doctor/ros2doctor/api/platform.py
index 02d2c3634..4d50828c1 100644
--- a/ros2doctor/ros2doctor/api/platform.py
+++ b/ros2doctor/ros2doctor/api/platform.py
@@ -33,18 +33,18 @@ def _check_platform_helper() -> Tuple[str, dict, dict]:
     """
     distro_name = os.environ.get('ROS_DISTRO')
     if not distro_name:
-        doctor_warn('ROS_DISTRO is not set.')
+        doctor_warn()('ERROR: ROS_DISTRO is not set.')
         return
-    else:
-        distro_name = distro_name.lower()
+    distro_name = distro_name.lower()
     u = rosdistro.get_index_url()
     if not u:
-        doctor_warn('Unable to access ROSDISTRO_INDEX_URL or DEFAULT_INDEX_URL.')
+        doctor_warn()('ERROR: Unable to access ROSDISTRO_INDEX_URL or DEFAULT_INDEX_URL. '
+            'Check network setting to make sure machine is connected to internet.')
         return
     i = rosdistro.get_index(u)
     distro_info = i.distributions.get(distro_name)
     if not distro_info:
-        doctor_warn(f"Distribution name {distro_name} is not found")
+        doctor_warn()(f'Distribution name {distro_name} is not found')
         return
     distro_data = rosdistro.get_distribution(i, distro_name).get_data()
     return distro_name, distro_info, distro_data
@@ -61,19 +61,22 @@ def check(self):
         result = Result()
         distros = _check_platform_helper()
         if not distros:
-            result.add_error('ERROR: Missing rosdistro info. Unable to check platform.')
+            doctor_warn()('ERROR: Missing rosdistro info. Unable to check platform.')
+            result.add_error()
             return result
         distro_name, distro_info, _ = distros
 
         # check distro status
         if distro_info.get('distribution_status') == 'prerelease':
-            result.add_warning(f'Distribution {distro_name} is not fully supported or tested. '
-                               'To get more consistent features, download a stable version at '
-                               'https://index.ros.org/doc/ros2/Installation/')
+            doctor_warn()(f'Distribution {distro_name} is not fully supported or tested. '
+                'To get more consistent features, download a stable version at '
+                'https://index.ros.org/doc/ros2/Installation/')
+            result.add_warning()
         elif distro_info.get('distribution_status') == 'end-of-life':
-            result.add_warning(f'Distribution {distro_name} is no longer supported or deprecated. '
-                               'To get the latest features, download the new versions at '
-                               'https://index.ros.org/doc/ros2/Installation/')
+            doctor_warn()(f'Distribution {distro_name} is no longer supported or deprecated. '
+                'To get the latest features, download the new versions at '
+                'https://index.ros.org/doc/ros2/Installation/')
+            result.add_warning()
         return result
 
 
diff --git a/ros2doctor/ros2doctor/api/topic.py b/ros2doctor/ros2doctor/api/topic.py
index bf899e4af..c0de9ce83 100644
--- a/ros2doctor/ros2doctor/api/topic.py
+++ b/ros2doctor/ros2doctor/api/topic.py
@@ -20,7 +20,7 @@
 from ros2doctor.api import DoctorReport
 from ros2doctor.api import Report
 from ros2doctor.api import Result
-
+from ros2doctor.api.format import doctor_warn
 
 def _get_topic_names() -> List:
     """Get all topic names using rclpy API."""
@@ -49,9 +49,11 @@ def check(self):
                 pub_count = node.count_publishers(topic)
                 sub_count = node.count_subscribers(topic)
                 if pub_count > sub_count:
-                    result.add_warning(f'Publisher without subscriber detected on {topic}.')
+                    doctor_warn()(f'Publisher without subscriber detected on {topic}.')
+                    result.add_warning()
                 elif pub_count < sub_count:
-                    result.add_warning(f'Subscriber without publisher detected on {topic}.')
+                    doctor_warn()(f'Subscriber without publisher detected on {topic}.')
+                    result.add_warning()
         return result
 
 
diff --git a/ros2doctor/ros2doctor/command/doctor.py b/ros2doctor/ros2doctor/command/doctor.py
index 6d8df274b..6a4c7a396 100644
--- a/ros2doctor/ros2doctor/command/doctor.py
+++ b/ros2doctor/ros2doctor/command/doctor.py
@@ -46,16 +46,16 @@ def main(self, *, parser, args):
             return
 
         # `ros2 doctor
-        failed_cats, fail, total = run_checks(include_warnings=args.include_warnings)
+        fail_category, fail, total = run_checks(include_warnings=args.include_warnings)
         if fail:
-            print('\n%d/%d checks failed\n' % (fail, total))
-            print('Failed modules:', *failed_cats)
+            print(f'\n{fail}/{total} check(s) failed\n')
+            print('Failed modules:', *fail_category)
         else:
-            print('\nAll %d checks passed\n' % total)
+            print(f'\nAll {total} checks passed\n')
 
         # `ros2 doctor -rf`
         if args.report_failed and fail != 0:
-            fail_reports = generate_reports(categories=failed_cats)
+            fail_reports = generate_reports(categories=fail_category)
             for report_obj in fail_reports:
                 format_print(report_obj)
 

From 3f090084fef0ad51ccdc757b1bba2b1b5d97e0a8 Mon Sep 17 00:00:00 2001
From: claireyywang <clairewang@openrobotics.org>
Date: Wed, 29 Jan 2020 16:56:26 -0800
Subject: [PATCH 3/7] update print statements

Signed-off-by: claireyywang <clairewang@openrobotics.org>
---
 ros2doctor/ros2doctor/api/__init__.py | 18 +++++++++---------
 ros2doctor/ros2doctor/api/format.py   |  4 ++--
 ros2doctor/ros2doctor/api/network.py  |  3 +--
 ros2doctor/ros2doctor/api/package.py  | 11 ++++-------
 4 files changed, 16 insertions(+), 20 deletions(-)

diff --git a/ros2doctor/ros2doctor/api/__init__.py b/ros2doctor/ros2doctor/api/__init__.py
index 47b07de1d..3c7e5e0ea 100644
--- a/ros2doctor/ros2doctor/api/__init__.py
+++ b/ros2doctor/ros2doctor/api/__init__.py
@@ -85,28 +85,28 @@ def run_checks(*, include_warnings=False) -> Tuple[Set[str], int, int]:
     :return: 3-tuple (categories of failed checks, number of failed checks,
              total number of checks)
     """
-    failed_cats = set()  # remove repeating elements
+    fail_categories = set()  # remove repeating elements
     fail = 0
     total = 0
     for check_entry_pt in iter_entry_points('ros2doctor.checks'):
         try:
             check_class = check_entry_pt.load()
         except (ImportError, UnknownExtra):
-            doctor_warn()(f'Check entry point {check_entry_pt.name} fails to load.', RuntimeWarning)
+            doctor_warn()(f'Check entry point {check_entry_pt.name} fails to load.')
         try:
             check_instance = check_class()
         except Exception:
-            doctor_warn()(f'Unable to instantiate check object from {check_entry_pt.name}.', RuntimeWarning)
+            doctor_warn()(f'Unable to instantiate check object from {check_entry_pt.name}.')
         try:
             check_category = check_instance.category()
             result = check_instance.check()
             if result.error or (include_warnings and result.warning):
                 fail += 1
-                failed_cats.add(check_category)
+                fail_categories.add(check_category)
             total += 1
         except Exception:
-            doctor_warn()(f'Fail to call {check_entry_pt.name} class functions.', RuntimeWarning)
-    return failed_cats, fail, total
+            doctor_warn()(f'Fail to call {check_entry_pt.name} class functions.')
+    return fail_categories, fail, total
 
 
 def generate_reports(*, categories=None) -> List[Report]:
@@ -120,11 +120,11 @@ def generate_reports(*, categories=None) -> List[Report]:
         try:
             report_class = report_entry_pt.load()
         except (ImportError, UnknownExtra):
-            doctor_warn()(f'Report entry point {report_entry_pt.name} fails to load.', RuntimeWarning)
+            doctor_warn()(f'Report entry point {report_entry_pt.name} fails to load.')
         try:
             report_instance = report_class()
         except Exception:
-            doctor_warn()(f'Unable to instantiate report object from {report_entry_pt.name}.', RuntimeWarning)
+            doctor_warn()(f'Unable to instantiate report object from {report_entry_pt.name}.')
         try:
             report_category = report_instance.category()
             report = report_instance.report()
@@ -134,5 +134,5 @@ def generate_reports(*, categories=None) -> List[Report]:
             else:
                 reports.append(report)
         except Exception:
-            doctor_warn()(f'Fail to call {report_entry_pt.name} class functions.', RuntimeWarning)
+            doctor_warn()(f'Fail to call {report_entry_pt.name} class functions.')
     return reports
diff --git a/ros2doctor/ros2doctor/api/format.py b/ros2doctor/ros2doctor/api/format.py
index 67abd846c..b33a07606 100644
--- a/ros2doctor/ros2doctor/api/format.py
+++ b/ros2doctor/ros2doctor/api/format.py
@@ -23,7 +23,7 @@ def format_print(report):
 
     :param report: Report object with name and items list
     """
-    print('\n ', report.name)
+    print('\n  ', report.name)
     if report.items:
         padding_num = compute_padding(report.items)
     for item_name, item_content in report.items:
@@ -52,6 +52,6 @@ def doctor_warn() -> None:
     :param msg: warning message to be printed
     """
     def custom_warning_format(message, category, filename, lineno, file=None, line=None):
-        return '%s:%s: %s: %s\n' % (filename, lineno, category.__name__, message)
+        return f'{filename}:{lineno}: {category.__name__}: {message}\n'
     warnings.formatwarning = custom_warning_format
     return warnings.warn
diff --git a/ros2doctor/ros2doctor/api/network.py b/ros2doctor/ros2doctor/api/network.py
index c38a5fe6d..93f6626a5 100644
--- a/ros2doctor/ros2doctor/api/network.py
+++ b/ros2doctor/ros2doctor/api/network.py
@@ -14,7 +14,6 @@
 
 import os
 from typing import Tuple
-import warnings
 
 from ros2doctor.api import DoctorCheck
 from ros2doctor.api import DoctorReport
@@ -26,7 +25,7 @@
     import ifcfg
 except ImportError:  # check import error for windows and osx
     doctor_warn()('Unable to import ifcfg. '
-        'Use `python -m pip install ifcfg` to install needed package.')
+        'Use `python3 -m pip install ifcfg` to install needed package.')
 
 
 def _is_unix_like_platform() -> bool:
diff --git a/ros2doctor/ros2doctor/api/package.py b/ros2doctor/ros2doctor/api/package.py
index a48a29a17..60874909f 100644
--- a/ros2doctor/ros2doctor/api/package.py
+++ b/ros2doctor/ros2doctor/api/package.py
@@ -51,9 +51,9 @@ def get_distro_package_versions() -> dict:
     if not distro_info:
         doctor_warn()(f'Distribution name {distro_name} is not found')
         return
-    distro_data = distro_info.get_data()
-    repos_info = distro_data.get('repositories')
-    if not repos_info:
+    try:
+        repos_info = distro_info.get_data().get('repositories')
+    except AttributeError:
         doctor_warn()('No repository information found.')
         return
     distro_package_vers = {}
@@ -161,11 +161,8 @@ def category(self):
     def report(self):
         """Report packages within the directory where command is called."""
         report = Report('PACKAGE VERSIONS')
-        try:
-            distro_package_vers = get_distro_package_versions()
-        except (AttributeError, RuntimeError, URLError):
-            return report
         local_package_vers = get_local_package_versions()
+        distro_package_vers = get_distro_package_versions()
         if not local_package_vers or not distro_package_vers:
             return report
         for name, local_ver_str in local_package_vers.items():

From 17e90bbbbd1e2992196d38f5629f3f150f3b278c Mon Sep 17 00:00:00 2001
From: claireyywang <clairewang@openrobotics.org>
Date: Wed, 29 Jan 2020 17:02:39 -0800
Subject: [PATCH 4/7] remove None return and add error catching

Signed-off-by: claireyywang <clairewang@openrobotics.org>
---
 ros2doctor/ros2doctor/api/__init__.py | 6 +++---
 ros2doctor/ros2doctor/api/format.py   | 3 ++-
 ros2doctor/ros2doctor/api/platform.py | 5 ++++-
 3 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/ros2doctor/ros2doctor/api/__init__.py b/ros2doctor/ros2doctor/api/__init__.py
index 3c7e5e0ea..de025d915 100644
--- a/ros2doctor/ros2doctor/api/__init__.py
+++ b/ros2doctor/ros2doctor/api/__init__.py
@@ -56,7 +56,7 @@ def __init__(self, name: str):
         self.name = name
         self.items = []
 
-    def add_to_report(self, item_name: str, item_info: str) -> None:
+    def add_to_report(self, item_name: str, item_info: str):
         """Add report content to items list (list of string tuples)."""
         self.items.append((item_name, item_info))
 
@@ -71,10 +71,10 @@ def __init__(self):
         self.error = 0
         self.warning = 0
 
-    def add_error(self) -> None:
+    def add_error(self):
         self.error += 1
 
-    def add_warning(self) -> None:
+    def add_warning(self):
         self.warning += 1
 
 
diff --git a/ros2doctor/ros2doctor/api/format.py b/ros2doctor/ros2doctor/api/format.py
index b33a07606..f7b5ef718 100644
--- a/ros2doctor/ros2doctor/api/format.py
+++ b/ros2doctor/ros2doctor/api/format.py
@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from typing import Callable
 from typing import List
 from typing import Tuple
 import warnings
@@ -45,7 +46,7 @@ def compute_padding(report_items: List[Tuple[str, str]]) -> int:
     return padding
 
 
-def doctor_warn() -> None:
+def doctor_warn() -> Callable:
     """
     Print customized warning message with package and line info.
 
diff --git a/ros2doctor/ros2doctor/api/platform.py b/ros2doctor/ros2doctor/api/platform.py
index 4d50828c1..566a8aa74 100644
--- a/ros2doctor/ros2doctor/api/platform.py
+++ b/ros2doctor/ros2doctor/api/platform.py
@@ -46,7 +46,10 @@ def _check_platform_helper() -> Tuple[str, dict, dict]:
     if not distro_info:
         doctor_warn()(f'Distribution name {distro_name} is not found')
         return
-    distro_data = rosdistro.get_distribution(i, distro_name).get_data()
+    try:
+        distro_data = rosdistro.get_distribution(i, distro_name).get_data()
+    except AttributeError:
+        distro_data = ''
     return distro_name, distro_info, distro_data
 
 

From d8af88b08c9769e6468da11c741f803e47133774 Mon Sep 17 00:00:00 2001
From: claireyywang <clairewang@openrobotics.org>
Date: Wed, 29 Jan 2020 17:11:47 -0800
Subject: [PATCH 5/7] update to hanging indentation

Signed-off-by: claireyywang <clairewang@openrobotics.org>
---
 ros2doctor/ros2doctor/api/network.py  |  9 ++++++---
 ros2doctor/ros2doctor/api/package.py  | 20 ++++++++++++--------
 ros2doctor/ros2doctor/api/platform.py |  9 ++++++---
 ros2doctor/ros2doctor/api/topic.py    |  1 +
 4 files changed, 25 insertions(+), 14 deletions(-)

diff --git a/ros2doctor/ros2doctor/api/network.py b/ros2doctor/ros2doctor/api/network.py
index 93f6626a5..c84a800fb 100644
--- a/ros2doctor/ros2doctor/api/network.py
+++ b/ros2doctor/ros2doctor/api/network.py
@@ -24,7 +24,8 @@
 try:
     import ifcfg
 except ImportError:  # check import error for windows and osx
-    doctor_warn()('Unable to import ifcfg. '
+    doctor_warn()(
+        'Unable to import ifcfg. '
         'Use `python3 -m pip install ifcfg` to install needed package.')
 
 
@@ -62,7 +63,8 @@ def check(self):
         try:
             ifcfg_ifaces = ifcfg.interfaces()
         except NameError:
-            doctor_warn()('ERROR: `ifcfg` module is not imported. '
+            doctor_warn()(
+                'ERROR: `ifcfg` module is not imported. '
                 'Unable to run network check.')
             result.add_error()
             return result
@@ -71,7 +73,8 @@ def check(self):
         if not _is_unix_like_platform():
             if not has_loopback and not has_non_loopback:
                 # no flags found, otherwise one of them should be True.
-                doctor_warn()('ERROR: No flags found. '
+                doctor_warn()(
+                    'ERROR: No flags found. '
                     'Run `ipconfig` on Windows or '
                     'install `ifconfig` on Unix to check network interfaces.')
                 result.add_error()
diff --git a/ros2doctor/ros2doctor/api/package.py b/ros2doctor/ros2doctor/api/package.py
index 60874909f..a5857a060 100644
--- a/ros2doctor/ros2doctor/api/package.py
+++ b/ros2doctor/ros2doctor/api/package.py
@@ -13,9 +13,7 @@
 # limitations under the License.
 
 import os
-from typing import List
 import textwrap
-from urllib.error import URLError
 
 from ament_index_python import get_packages_with_prefixes
 from catkin_pkg.package import parse_package
@@ -43,7 +41,8 @@ def get_distro_package_versions() -> dict:
     distro_name = distro_name.lower()
     url = rosdistro.get_index_url()
     if not url:
-        doctor_warn()('ERROR: Unable to access ROSDISTRO_INDEX_URL or DEFAULT_INDEX_URL. '
+        doctor_warn()(
+            'ERROR: Unable to access ROSDISTRO_INDEX_URL or DEFAULT_INDEX_URL. '
             'Check network setting to make sure machine is connected to internet.')
         return
     i = rosdistro.get_index(url)
@@ -106,25 +105,30 @@ def compare_versions(result: Result, local_packages: dict, distro_packages: dict
         local_ver = version.parse(local_ver_str).base_version
         required_ver = version.parse(required_ver_str).base_version
         if local_ver < required_ver:
-            doctor_warn()(f'{name} has been updated to a new version.'
+            doctor_warn()(
+                f'{name} has been updated to a new version.'
                 f' local: {local_ver} <'
                 f' required: {required_ver}')
             result.add_warning()
     if missing_req:
         if len(missing_req) > 100:
-            doctor_warn()('Cannot find required versions of packages: ' +
+            doctor_warn()(
+                'Cannot find required versions of packages: ' +
                 textwrap.shorten(missing_req, width=100) +
                 ' Use `ros2 doctor --report` to see full list.')
         else:
-            doctor_warn()('Cannot find required versions of packages: ' +
+            doctor_warn()(
+                'Cannot find required versions of packages: ' +
                 missing_req)
     if missing_local:
         if len(missing_local) > 100:
-            doctor_warn()('Cannot find local versions of packages: ' +
+            doctor_warn()(
+                'Cannot find local versions of packages: ' +
                 textwrap.shorten(missing_local, width=100) +
                 ' Use `ros2 doctor --report` to see full list.')
         else:
-            doctor_warn()('Cannot find local versions of packages: ' +
+            doctor_warn()(
+                'Cannot find local versions of packages: ' +
                 missing_local)
 
 
diff --git a/ros2doctor/ros2doctor/api/platform.py b/ros2doctor/ros2doctor/api/platform.py
index 566a8aa74..3a90ce43c 100644
--- a/ros2doctor/ros2doctor/api/platform.py
+++ b/ros2doctor/ros2doctor/api/platform.py
@@ -38,7 +38,8 @@ def _check_platform_helper() -> Tuple[str, dict, dict]:
     distro_name = distro_name.lower()
     u = rosdistro.get_index_url()
     if not u:
-        doctor_warn()('ERROR: Unable to access ROSDISTRO_INDEX_URL or DEFAULT_INDEX_URL. '
+        doctor_warn()(
+            'ERROR: Unable to access ROSDISTRO_INDEX_URL or DEFAULT_INDEX_URL. '
             'Check network setting to make sure machine is connected to internet.')
         return
     i = rosdistro.get_index(u)
@@ -71,12 +72,14 @@ def check(self):
 
         # check distro status
         if distro_info.get('distribution_status') == 'prerelease':
-            doctor_warn()(f'Distribution {distro_name} is not fully supported or tested. '
+            doctor_warn()(
+                f'Distribution {distro_name} is not fully supported or tested. '
                 'To get more consistent features, download a stable version at '
                 'https://index.ros.org/doc/ros2/Installation/')
             result.add_warning()
         elif distro_info.get('distribution_status') == 'end-of-life':
-            doctor_warn()(f'Distribution {distro_name} is no longer supported or deprecated. '
+            doctor_warn()(
+                f'Distribution {distro_name} is no longer supported or deprecated. '
                 'To get the latest features, download the new versions at '
                 'https://index.ros.org/doc/ros2/Installation/')
             result.add_warning()
diff --git a/ros2doctor/ros2doctor/api/topic.py b/ros2doctor/ros2doctor/api/topic.py
index c0de9ce83..b376df7fb 100644
--- a/ros2doctor/ros2doctor/api/topic.py
+++ b/ros2doctor/ros2doctor/api/topic.py
@@ -22,6 +22,7 @@
 from ros2doctor.api import Result
 from ros2doctor.api.format import doctor_warn
 
+
 def _get_topic_names() -> List:
     """Get all topic names using rclpy API."""
     white_list = ['/parameter_events', '/rosout']

From 61657e31580bce1ab85330eeced4b918905d01ba Mon Sep 17 00:00:00 2001
From: claireyywang <clairewang@openrobotics.org>
Date: Mon, 3 Feb 2020 17:13:07 -0800
Subject: [PATCH 6/7] specify stacklevel; add doctor_error

Signed-off-by: claireyywang <clairewang@openrobotics.org>
---
 ros2doctor/ros2doctor/api/__init__.py | 14 +++++-----
 ros2doctor/ros2doctor/api/format.py   | 40 +++++++++++++++++++++++----
 ros2doctor/ros2doctor/api/network.py  | 19 +++++++------
 ros2doctor/ros2doctor/api/package.py  | 25 +++++++++--------
 ros2doctor/ros2doctor/api/platform.py | 15 +++++-----
 ros2doctor/ros2doctor/api/topic.py    |  4 +--
 6 files changed, 75 insertions(+), 42 deletions(-)

diff --git a/ros2doctor/ros2doctor/api/__init__.py b/ros2doctor/ros2doctor/api/__init__.py
index de025d915..1ff2ebe0a 100644
--- a/ros2doctor/ros2doctor/api/__init__.py
+++ b/ros2doctor/ros2doctor/api/__init__.py
@@ -56,7 +56,7 @@ def __init__(self, name: str):
         self.name = name
         self.items = []
 
-    def add_to_report(self, item_name: str, item_info: str):
+    def add_to_report(self, item_name: str, item_info: str) -> None:
         """Add report content to items list (list of string tuples)."""
         self.items.append((item_name, item_info))
 
@@ -92,11 +92,11 @@ def run_checks(*, include_warnings=False) -> Tuple[Set[str], int, int]:
         try:
             check_class = check_entry_pt.load()
         except (ImportError, UnknownExtra):
-            doctor_warn()(f'Check entry point {check_entry_pt.name} fails to load.')
+            doctor_warn(f'Check entry point {check_entry_pt.name} fails to load.')
         try:
             check_instance = check_class()
         except Exception:
-            doctor_warn()(f'Unable to instantiate check object from {check_entry_pt.name}.')
+            doctor_warn(f'Unable to instantiate check object from {check_entry_pt.name}.')
         try:
             check_category = check_instance.category()
             result = check_instance.check()
@@ -105,7 +105,7 @@ def run_checks(*, include_warnings=False) -> Tuple[Set[str], int, int]:
                 fail_categories.add(check_category)
             total += 1
         except Exception:
-            doctor_warn()(f'Fail to call {check_entry_pt.name} class functions.')
+            doctor_warn(f'Fail to call {check_entry_pt.name} class functions.')
     return fail_categories, fail, total
 
 
@@ -120,11 +120,11 @@ def generate_reports(*, categories=None) -> List[Report]:
         try:
             report_class = report_entry_pt.load()
         except (ImportError, UnknownExtra):
-            doctor_warn()(f'Report entry point {report_entry_pt.name} fails to load.')
+            doctor_warn(f'Report entry point {report_entry_pt.name} fails to load.')
         try:
             report_instance = report_class()
         except Exception:
-            doctor_warn()(f'Unable to instantiate report object from {report_entry_pt.name}.')
+            doctor_warn(f'Unable to instantiate report object from {report_entry_pt.name}.')
         try:
             report_category = report_instance.category()
             report = report_instance.report()
@@ -134,5 +134,5 @@ def generate_reports(*, categories=None) -> List[Report]:
             else:
                 reports.append(report)
         except Exception:
-            doctor_warn()(f'Fail to call {report_entry_pt.name} class functions.')
+            doctor_warn(f'Fail to call {report_entry_pt.name} class functions.')
     return reports
diff --git a/ros2doctor/ros2doctor/api/format.py b/ros2doctor/ros2doctor/api/format.py
index f7b5ef718..f172e6bc4 100644
--- a/ros2doctor/ros2doctor/api/format.py
+++ b/ros2doctor/ros2doctor/api/format.py
@@ -46,13 +46,43 @@ def compute_padding(report_items: List[Tuple[str, str]]) -> int:
     return padding
 
 
-def doctor_warn() -> Callable:
+
+def custom_warning_format(msg, cat, filename, linenum, file=None, line=None):
+    return '%s: %s: %s: %s\n' % (filename, linenum, cat.__name__, msg)
+
+
+class CustomWarningFormat:
+    """Support custom warning format without modifying default format."""
+
+    def __enter__(self):
+        self._default_format = warnings.formatwarning
+        warnings.formatwarning = custom_warning_format
+
+    def __exit__(self, t, v, trb):
+        """
+        Define exit action for context manager.
+        :param t: type
+        :param v: value
+        :param trb: traceback
+        """
+        warnings.formatwarning = self._default_format
+
+
+def doctor_warn(msg: str) -> None:
     """
     Print customized warning message with package and line info.
 
     :param msg: warning message to be printed
     """
-    def custom_warning_format(message, category, filename, lineno, file=None, line=None):
-        return f'{filename}:{lineno}: {category.__name__}: {message}\n'
-    warnings.formatwarning = custom_warning_format
-    return warnings.warn
+    with CustomWarningFormat():
+        warnings.warn(msg, stacklevel=2)
+
+
+def doctor_error(msg: str) -> None:
+    """
+    Print customized error message with package and line info.
+
+    :param msg: error message to be printed
+    """
+    with CustomWarningFormat():
+        warnings.warn(f'ERROR: {msg}', stacklevel=2)
\ No newline at end of file
diff --git a/ros2doctor/ros2doctor/api/network.py b/ros2doctor/ros2doctor/api/network.py
index c84a800fb..00f82d546 100644
--- a/ros2doctor/ros2doctor/api/network.py
+++ b/ros2doctor/ros2doctor/api/network.py
@@ -20,11 +20,12 @@
 from ros2doctor.api import Report
 from ros2doctor.api import Result
 from ros2doctor.api.format import doctor_warn
+from ros2doctor.api.format import doctor_error
 
 try:
     import ifcfg
 except ImportError:  # check import error for windows and osx
-    doctor_warn()(
+    doctor_warn(
         'Unable to import ifcfg. '
         'Use `python3 -m pip install ifcfg` to install needed package.')
 
@@ -63,8 +64,8 @@ def check(self):
         try:
             ifcfg_ifaces = ifcfg.interfaces()
         except NameError:
-            doctor_warn()(
-                'ERROR: `ifcfg` module is not imported. '
+            doctor_error(
+                '`ifcfg` module is not imported. '
                 'Unable to run network check.')
             result.add_error()
             return result
@@ -73,20 +74,20 @@ def check(self):
         if not _is_unix_like_platform():
             if not has_loopback and not has_non_loopback:
                 # no flags found, otherwise one of them should be True.
-                doctor_warn()(
-                    'ERROR: No flags found. '
+                doctor_error(
+                    'No flags found. '
                     'Run `ipconfig` on Windows or '
                     'install `ifconfig` on Unix to check network interfaces.')
                 result.add_error()
                 return result
         if not has_loopback:
-            doctor_warn()('ERROR: No loopback IP address is found.')
+            doctor_error('No loopback IP address is found.')
             result.add_error()
         if not has_non_loopback:
-            doctor_warn()('Only loopback IP address is found.')
+            doctor_warn('Only loopback IP address is found.')
             result.add_warning()
         if not has_multicast:
-            doctor_warn()('No multicast IP address is found.')
+            doctor_warn('No multicast IP address is found.')
             result.add_warning()
         return result
 
@@ -103,7 +104,7 @@ def report(self):
         try:
             ifcfg_ifaces = ifcfg.interfaces()
         except NameError:
-            doctor_warn()('ERROR: ifcfg is not imported. Unable to generate network report.')
+            doctor_error('ifcfg is not imported. Unable to generate network report.')
             return Report('')
 
         network_report = Report('NETWORK CONFIGURATION')
diff --git a/ros2doctor/ros2doctor/api/package.py b/ros2doctor/ros2doctor/api/package.py
index a5857a060..ad775f304 100644
--- a/ros2doctor/ros2doctor/api/package.py
+++ b/ros2doctor/ros2doctor/api/package.py
@@ -24,6 +24,7 @@
 from ros2doctor.api import Report
 from ros2doctor.api import Result
 from ros2doctor.api.format import doctor_warn
+from ros2doctor.api.format import doctor_error
 
 import rosdistro
 
@@ -36,24 +37,24 @@ def get_distro_package_versions() -> dict:
     """
     distro_name = os.environ.get('ROS_DISTRO')
     if not distro_name:
-        doctor_warn()('ERROR: ROS_DISTRO is not set.')
+        doctor_error('ROS_DISTRO is not set.')
         return
     distro_name = distro_name.lower()
     url = rosdistro.get_index_url()
     if not url:
-        doctor_warn()(
-            'ERROR: Unable to access ROSDISTRO_INDEX_URL or DEFAULT_INDEX_URL. '
+        doctor_error(
+            'Unable to access ROSDISTRO_INDEX_URL or DEFAULT_INDEX_URL. '
             'Check network setting to make sure machine is connected to internet.')
         return
     i = rosdistro.get_index(url)
     distro_info = rosdistro.get_distribution(i, distro_name)
     if not distro_info:
-        doctor_warn()(f'Distribution name {distro_name} is not found')
+        doctor_warn(f'Distribution name {distro_name} is not found')
         return
     try:
         repos_info = distro_info.get_data().get('repositories')
     except AttributeError:
-        doctor_warn()('No repository information found.')
+        doctor_warn('No repository information found.')
         return
     distro_package_vers = {}
     for _, info in repos_info.items():
@@ -105,29 +106,29 @@ def compare_versions(result: Result, local_packages: dict, distro_packages: dict
         local_ver = version.parse(local_ver_str).base_version
         required_ver = version.parse(required_ver_str).base_version
         if local_ver < required_ver:
-            doctor_warn()(
+            doctor_warn(
                 f'{name} has been updated to a new version.'
                 f' local: {local_ver} <'
                 f' required: {required_ver}')
             result.add_warning()
     if missing_req:
         if len(missing_req) > 100:
-            doctor_warn()(
+            doctor_warn(
                 'Cannot find required versions of packages: ' +
                 textwrap.shorten(missing_req, width=100) +
                 ' Use `ros2 doctor --report` to see full list.')
         else:
-            doctor_warn()(
+            doctor_warn(
                 'Cannot find required versions of packages: ' +
                 missing_req)
     if missing_local:
         if len(missing_local) > 100:
-            doctor_warn()(
+            doctor_warn(
                 'Cannot find local versions of packages: ' +
                 textwrap.shorten(missing_local, width=100) +
                 ' Use `ros2 doctor --report` to see full list.')
         else:
-            doctor_warn()(
+            doctor_warn(
                 'Cannot find local versions of packages: ' +
                 missing_local)
 
@@ -143,11 +144,11 @@ def check(self):
         result = Result()
         distro_package_vers = get_distro_package_versions()
         if not distro_package_vers:
-            doctor_warn()('ERROR: distro packages info is not found.')
+            doctor_error('distro packages info is not found.')
             result.add_error()
         local_package_vers = get_local_package_versions()
         if not local_package_vers:
-            doctor_warn()('ERROR: local package info is not found.')
+            doctor_error('local package info is not found.')
             result.add_error()
         if result.error != 0:
             return result
diff --git a/ros2doctor/ros2doctor/api/platform.py b/ros2doctor/ros2doctor/api/platform.py
index 3a90ce43c..ae4faa80b 100644
--- a/ros2doctor/ros2doctor/api/platform.py
+++ b/ros2doctor/ros2doctor/api/platform.py
@@ -21,6 +21,7 @@
 from ros2doctor.api import Report
 from ros2doctor.api import Result
 from ros2doctor.api.format import doctor_warn
+from ros2doctor.api.format import doctor_error
 
 import rosdistro
 
@@ -33,19 +34,19 @@ def _check_platform_helper() -> Tuple[str, dict, dict]:
     """
     distro_name = os.environ.get('ROS_DISTRO')
     if not distro_name:
-        doctor_warn()('ERROR: ROS_DISTRO is not set.')
+        doctor_error('ROS_DISTRO is not set.')
         return
     distro_name = distro_name.lower()
     u = rosdistro.get_index_url()
     if not u:
-        doctor_warn()(
-            'ERROR: Unable to access ROSDISTRO_INDEX_URL or DEFAULT_INDEX_URL. '
+        doctor_error(
+            'Unable to access ROSDISTRO_INDEX_URL or DEFAULT_INDEX_URL. '
             'Check network setting to make sure machine is connected to internet.')
         return
     i = rosdistro.get_index(u)
     distro_info = i.distributions.get(distro_name)
     if not distro_info:
-        doctor_warn()(f'Distribution name {distro_name} is not found')
+        doctor_warn(f'Distribution name {distro_name} is not found')
         return
     try:
         distro_data = rosdistro.get_distribution(i, distro_name).get_data()
@@ -65,20 +66,20 @@ def check(self):
         result = Result()
         distros = _check_platform_helper()
         if not distros:
-            doctor_warn()('ERROR: Missing rosdistro info. Unable to check platform.')
+            doctor_error('Missing rosdistro info. Unable to check platform.')
             result.add_error()
             return result
         distro_name, distro_info, _ = distros
 
         # check distro status
         if distro_info.get('distribution_status') == 'prerelease':
-            doctor_warn()(
+            doctor_warn(
                 f'Distribution {distro_name} is not fully supported or tested. '
                 'To get more consistent features, download a stable version at '
                 'https://index.ros.org/doc/ros2/Installation/')
             result.add_warning()
         elif distro_info.get('distribution_status') == 'end-of-life':
-            doctor_warn()(
+            doctor_warn(
                 f'Distribution {distro_name} is no longer supported or deprecated. '
                 'To get the latest features, download the new versions at '
                 'https://index.ros.org/doc/ros2/Installation/')
diff --git a/ros2doctor/ros2doctor/api/topic.py b/ros2doctor/ros2doctor/api/topic.py
index b376df7fb..b7f2f4870 100644
--- a/ros2doctor/ros2doctor/api/topic.py
+++ b/ros2doctor/ros2doctor/api/topic.py
@@ -50,10 +50,10 @@ def check(self):
                 pub_count = node.count_publishers(topic)
                 sub_count = node.count_subscribers(topic)
                 if pub_count > sub_count:
-                    doctor_warn()(f'Publisher without subscriber detected on {topic}.')
+                    doctor_warn(f'Publisher without subscriber detected on {topic}.')
                     result.add_warning()
                 elif pub_count < sub_count:
-                    doctor_warn()(f'Subscriber without publisher detected on {topic}.')
+                    doctor_warn(f'Subscriber without publisher detected on {topic}.')
                     result.add_warning()
         return result
 

From e931b6b43f6038862dc31cef61588c2d029e2e49 Mon Sep 17 00:00:00 2001
From: claireyywang <clairewang@openrobotics.org>
Date: Mon, 3 Feb 2020 17:28:16 -0800
Subject: [PATCH 7/7] fix code style

Signed-off-by: claireyywang <clairewang@openrobotics.org>
---
 ros2doctor/ros2doctor/api/format.py   | 5 ++---
 ros2doctor/ros2doctor/api/network.py  | 2 +-
 ros2doctor/ros2doctor/api/package.py  | 2 +-
 ros2doctor/ros2doctor/api/platform.py | 2 +-
 4 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/ros2doctor/ros2doctor/api/format.py b/ros2doctor/ros2doctor/api/format.py
index f172e6bc4..16e332c8b 100644
--- a/ros2doctor/ros2doctor/api/format.py
+++ b/ros2doctor/ros2doctor/api/format.py
@@ -12,7 +12,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from typing import Callable
 from typing import List
 from typing import Tuple
 import warnings
@@ -46,7 +45,6 @@ def compute_padding(report_items: List[Tuple[str, str]]) -> int:
     return padding
 
 
-
 def custom_warning_format(msg, cat, filename, linenum, file=None, line=None):
     return '%s: %s: %s: %s\n' % (filename, linenum, cat.__name__, msg)
 
@@ -61,6 +59,7 @@ def __enter__(self):
     def __exit__(self, t, v, trb):
         """
         Define exit action for context manager.
+
         :param t: type
         :param v: value
         :param trb: traceback
@@ -85,4 +84,4 @@ def doctor_error(msg: str) -> None:
     :param msg: error message to be printed
     """
     with CustomWarningFormat():
-        warnings.warn(f'ERROR: {msg}', stacklevel=2)
\ No newline at end of file
+        warnings.warn(f'ERROR: {msg}', stacklevel=2)
diff --git a/ros2doctor/ros2doctor/api/network.py b/ros2doctor/ros2doctor/api/network.py
index 00f82d546..0d76c55f0 100644
--- a/ros2doctor/ros2doctor/api/network.py
+++ b/ros2doctor/ros2doctor/api/network.py
@@ -19,8 +19,8 @@
 from ros2doctor.api import DoctorReport
 from ros2doctor.api import Report
 from ros2doctor.api import Result
-from ros2doctor.api.format import doctor_warn
 from ros2doctor.api.format import doctor_error
+from ros2doctor.api.format import doctor_warn
 
 try:
     import ifcfg
diff --git a/ros2doctor/ros2doctor/api/package.py b/ros2doctor/ros2doctor/api/package.py
index ad775f304..fa892cdc6 100644
--- a/ros2doctor/ros2doctor/api/package.py
+++ b/ros2doctor/ros2doctor/api/package.py
@@ -23,8 +23,8 @@
 from ros2doctor.api import DoctorReport
 from ros2doctor.api import Report
 from ros2doctor.api import Result
-from ros2doctor.api.format import doctor_warn
 from ros2doctor.api.format import doctor_error
+from ros2doctor.api.format import doctor_warn
 
 import rosdistro
 
diff --git a/ros2doctor/ros2doctor/api/platform.py b/ros2doctor/ros2doctor/api/platform.py
index ae4faa80b..84429d361 100644
--- a/ros2doctor/ros2doctor/api/platform.py
+++ b/ros2doctor/ros2doctor/api/platform.py
@@ -20,8 +20,8 @@
 from ros2doctor.api import DoctorReport
 from ros2doctor.api import Report
 from ros2doctor.api import Result
-from ros2doctor.api.format import doctor_warn
 from ros2doctor.api.format import doctor_error
+from ros2doctor.api.format import doctor_warn
 
 import rosdistro