7 files changed, 152 insertions, 23 deletions

diff --git a/.github/workflows/info.yml b/.github/workflows/lint.yml
index bb3a50847..1aa347a1b 100644
--- a/.github/workflows/info.yml
+++ b/.github/workflows/lint.yml
@@ -6,7 +6,7 @@ on:
     - 'keyboards/**'
 
 jobs:
-  info:
+  lint:
     runs-on: ubuntu-latest
 
     container: qmkfm/base_container
@@ -27,7 +27,7 @@ jobs:
         echo ${{ github.event.pull_request.base.sha }}
         echo '${{ steps.file_changes.outputs.files}}'
 
-    - name: Run qmk info
+    - name: Run qmk lint
       shell: 'bash {0}'
       run: |
         QMK_CHANGES=$(echo -e '${{ steps.file_changes.outputs.files}}')
@@ -45,10 +45,7 @@ jobs:
           if [[ $KEYMAP_ONLY -gt 0 ]]; then
             echo "linting ${KB}"
 
-            # TODO: info info always returns 0 - right now the only way to know failure is to inspect log lines
-            qmk info -l -kb ${KB} 2>&1 | tee /tmp/$$
-            !(grep -cq ☒ /tmp/$$)
-            : $((exit_code = $exit_code + $?))
+            qmk lint --keyboard ${KB}
           fi
         done
         exit $exit_code
diff --git a/docs/cli_commands.md b/docs/cli_commands.md
index c970b1efa..b10f5d499 100644
--- a/docs/cli_commands.md
+++ b/docs/cli_commands.md
@@ -178,6 +178,24 @@ Creates a keymap.json from a keymap.c.
 qmk c2json [--no-cpp] [-o OUTPUT] filename
 ```
 
+## `qmk lint`
+
+Checks over a keyboard and/or keymap and highlights common errors, problems, and anti-patterns.
+
+**Usage**:
+
+```
+qmk lint [-km KEYMAP] [-kb KEYBOARD] [--strict]
+```
+
+This command is directory aware. It will automatically fill in KEYBOARD and/or KEYMAP if you are in a keyboard or keymap directory.
+
+**Examples**:
+
+Do a basic lint check:
+
+    qmk lint -kb rominronin/katana60/rev2
+
 ## `qmk list-keyboards`
 
 This command lists all the keyboards currently defined in `qmk_firmware`
@@ -309,4 +327,3 @@ This command runs the python test suite. If you make changes to python code you
 ```
 qmk pytest
 ```
-
diff --git a/docs/hardware_keyboard_guidelines.md b/docs/hardware_keyboard_guidelines.md
index d49d0d092..742b56572 100644
--- a/docs/hardware_keyboard_guidelines.md
+++ b/docs/hardware_keyboard_guidelines.md
@@ -3,6 +3,25 @@
 Since starting, QMK has grown by leaps and bounds thanks to people like you who contribute to creating and maintaining our community keyboards. As we've grown we've discovered some patterns that work well, and ask that you conform to them to make it easier for other people to benefit from your hard work.
 
 
+## Use QMK Lint
+
+We have provided a tool, `qmk lint`, which will let you check over your keyboard for problems. We suggest using it frequently while working on your keyboard and keymap. 
+
+Example passing check:
+
+```
+$ qmk lint -kb rominronin/katana60/rev2
+Ψ Lint check passed!
+```
+
+Example failing check:
+
+```
+$ qmk lint -kb clueboard/66/rev3
+☒ Missing keyboards/clueboard/66/rev3/readme.md
+☒ Lint check failed!
+```
+
 ## Naming Your Keyboard/Project
 
 All keyboard names are in lower case, consisting only of letters, numbers, and underscore (`_`). Names may not begin with an underscore. Forward slash (`/`) is used as a sub-folder separation character.
diff --git a/lib/python/qmk/cli/__init__.py b/lib/python/qmk/cli/__init__.py
index 3868f94bb..77724a244 100644
--- a/lib/python/qmk/cli/__init__.py
+++ b/lib/python/qmk/cli/__init__.py
@@ -19,6 +19,7 @@ from . import hello
 from . import info
 from . import json
 from . import json2c
+from . import lint
 from . import list
 from . import kle2json
 from . import new
diff --git a/lib/python/qmk/cli/lint.py b/lib/python/qmk/cli/lint.py
new file mode 100644
index 000000000..74467021e
--- /dev/null
+++ b/lib/python/qmk/cli/lint.py
@@ -0,0 +1,70 @@
+"""Command to look over a keyboard/keymap and check for common mistakes.
+"""
+from milc import cli
+
+from qmk.decorators import automagic_keyboard, automagic_keymap
+from qmk.info import info_json
+from qmk.keymap import locate_keymap
+from qmk.path import is_keyboard, keyboard
+
+
+@cli.argument('--strict', action='store_true', help='Treat warnings as errors.')
+@cli.argument('-kb', '--keyboard', help='The keyboard to check.')
+@cli.argument('-km', '--keymap', help='The keymap to check.')
+@cli.subcommand('Check keyboard and keymap for common mistakes.')
+@automagic_keyboard
+@automagic_keymap
+def lint(cli):
+    """Check keyboard and keymap for common mistakes.
+    """
+    if not cli.config.lint.keyboard:
+        cli.log.error('Missing required argument: --keyboard')
+        cli.print_help()
+        return False
+
+    if not is_keyboard(cli.config.lint.keyboard):
+        cli.log.error('No such keyboard: %s', cli.config.lint.keyboard)
+        return False
+
+    # Gather data about the keyboard.
+    ok = True
+    keyboard_path = keyboard(cli.config.lint.keyboard)
+    keyboard_info = info_json(cli.config.lint.keyboard)
+    readme_path = keyboard_path / 'readme.md'
+
+    # Check for errors in the info.json
+    if keyboard_info['parse_errors']:
+        ok = False
+        cli.log.error('Errors found when generating info.json.')
+
+    if cli.config.lint.strict and keyboard_info['parse_warnings']:
+        ok = False
+        cli.log.error('Warnings found when generating info.json (Strict mode enabled.)')
+
+    # Check for a readme.md and warn if it doesn't exist
+    if not readme_path.exists():
+        ok = False
+        cli.log.error('Missing %s', readme_path)
+
+    # Keymap specific checks
+    if cli.config.lint.keymap:
+        keymap_path = locate_keymap(cli.config.lint.keyboard, cli.config.lint.keymap)
+
+        if not keymap_path:
+            ok = False
+            cli.log.error("Can't find %s keymap for %s keyboard.", cli.config.lint.keymap, cli.config.lint.keyboard)
+        else:
+            keymap_readme = keymap_path.parent / 'readme.md'
+            if not keymap_readme.exists():
+                cli.log.warning('Missing %s', keymap_readme)
+
+                if cli.config.lint.strict:
+                    ok = False
+
+    # Check and report the overall status
+    if ok:
+        cli.log.info('Lint check passed!')
+        return True
+
+    cli.log.error('Lint check failed!')
+    return False
diff --git a/lib/python/qmk/info.py b/lib/python/qmk/info.py
index e92c3335b..d73ba8cfb 100644
--- a/lib/python/qmk/info.py
+++ b/lib/python/qmk/info.py
@@ -28,6 +28,8 @@ def info_json(keyboard):
         'keyboard_folder': str(keyboard),
         'keymaps': {},
         'layouts': {},
+        'parse_errors': [],
+        'parse_warnings': [],
         'maintainer': 'qmk',
     }
 
@@ -36,7 +38,7 @@ def info_json(keyboard):
         info_data['keymaps'][keymap.name] = {'url': f'https://raw.githubusercontent.com/qmk/qmk_firmware/master/{keymap}/keymap.json'}
 
     # Populate layout data
-    for layout_name, layout_json in _find_all_layouts(keyboard, rules).items():
+    for layout_name, layout_json in _find_all_layouts(info_data, keyboard, rules).items():
         if not layout_name.startswith('LAYOUT_kc'):
             info_data['layouts'][layout_name] = layout_json
 
@@ -104,14 +106,16 @@ def _extract_rules_mk(info_data):
     mcu = rules.get('MCU')
 
     if mcu in CHIBIOS_PROCESSORS:
-        arm_processor_rules(info_data, rules)
+        return arm_processor_rules(info_data, rules)
+
     elif mcu in LUFA_PROCESSORS + VUSB_PROCESSORS:
-        avr_processor_rules(info_data, rules)
-    else:
-        cli.log.warning("%s: Unknown MCU: %s" % (info_data['keyboard_folder'], mcu))
-        unknown_processor_rules(info_data, rules)
+        return avr_processor_rules(info_data, rules)
 
-    return info_data
+    msg = "Unknown MCU: " + str(mcu)
+
+    _log_warning(info_data, msg)
+
+    return unknown_processor_rules(info_data, rules)
 
 
 def _search_keyboard_h(path):
@@ -127,7 +131,7 @@ def _search_keyboard_h(path):
     return layouts
 
 
-def _find_all_layouts(keyboard, rules):
+def _find_all_layouts(info_data, keyboard, rules):
     """Looks for layout macros associated with this keyboard.
     """
     layouts = _search_keyboard_h(Path(keyboard))
@@ -135,7 +139,7 @@ def _find_all_layouts(keyboard, rules):
     if not layouts:
         # If we didn't find any layouts above we widen our search. This is error
         # prone which is why we want to encourage people to follow the standard above.
-        cli.log.warning('%s: Falling back to searching for KEYMAP/LAYOUT macros.' % (keyboard))
+        _log_warning(info_data, 'Falling back to searching for KEYMAP/LAYOUT macros.')
         for file in glob('keyboards/%s/*.h' % keyboard):
             if file.endswith('.h'):
                 these_layouts = find_layouts(file)
@@ -153,11 +157,25 @@ def _find_all_layouts(keyboard, rules):
                 supported_layouts.remove(layout_name)
 
         if supported_layouts:
-            cli.log.error('%s: Missing LAYOUT() macro for %s' % (keyboard, ', '.join(supported_layouts)))
+            _log_error(info_data, 'Missing LAYOUT() macro for %s' % (', '.join(supported_layouts)))
 
     return layouts
 
 
+def _log_error(info_data, message):
+    """Send an error message to both JSON and the log.
+    """
+    info_data['parse_errors'].append(message)
+    cli.log.error('%s: %s', info_data.get('keyboard_folder', 'Unknown Keyboard!'), message)
+
+
+def _log_warning(info_data, message):
+    """Send a warning message to both JSON and the log.
+    """
+    info_data['parse_warnings'].append(message)
+    cli.log.warning('%s: %s', info_data.get('keyboard_folder', 'Unknown Keyboard!'), message)
+
+
 def arm_processor_rules(info_data, rules):
     """Setup the default info for an ARM board.
     """
@@ -216,7 +234,7 @@ def merge_info_jsons(keyboard, info_data):
             new_info_data = json.load(info_fd)
 
         if not isinstance(new_info_data, dict):
-            cli.log.error("Invalid file %s, root object should be a dictionary.", str(info_file))
+            _log_error(info_data, "Invalid file %s, root object should be a dictionary.", str(info_file))
             continue
 
         # Copy whitelisted keys into `info_data`
@@ -230,7 +248,8 @@ def merge_info_jsons(keyboard, info_data):
                 # Only pull in layouts we have a macro for
                 if layout_name in info_data['layouts']:
                     if info_data['layouts'][layout_name]['key_count'] != len(json_layout['layout']):
-                        cli.log.error('%s: %s: Number of elements in info.json does not match! info.json:%s != %s:%s', info_data['keyboard_folder'], layout_name, len(json_layout['layout']), layout_name, len(info_data['layouts'][layout_name]['layout']))
+                        msg = '%s: Number of elements in info.json does not match! info.json:%s != %s:%s'
+                        _log_error(info_data, msg % (layout_name, len(json_layout['layout']), layout_name, len(info_data['layouts'][layout_name]['layout'])))
                     else:
                         for i, key in enumerate(info_data['layouts'][layout_name]['layout']):
                             key.update(json_layout['layout'][i])
diff --git a/lib/python/qmk/path.py b/lib/python/qmk/path.py
index 591fad034..54def1d5d 100644
--- a/lib/python/qmk/path.py
+++ b/lib/python/qmk/path.py
@@ -28,15 +28,21 @@ def under_qmk_firmware():
         return None
 
 
-def keymap(keyboard):
+def keyboard(keyboard_name):
+    """Returns the path to a keyboard's directory relative to the qmk root.
+    """
+    return Path('keyboards') / keyboard_name
+
+
+def keymap(keyboard_name):
     """Locate the correct directory for storing a keymap.
 
     Args:
 
-        keyboard
+        keyboard_name
             The name of the keyboard. Example: clueboard/66/rev3
     """
-    keyboard_folder = Path('keyboards') / keyboard
+    keyboard_folder = keyboard(keyboard_name)
 
     for i in range(MAX_KEYBOARD_SUBFOLDERS):
         if (keyboard_folder / 'keymaps').exists():
@@ -45,7 +51,7 @@ def keymap(keyboard):
         keyboard_folder = keyboard_folder.parent
 
     logging.error('Could not find the keymaps directory!')
-    raise NoSuchKeyboardError('Could not find keymaps directory for: %s' % keyboard)
+    raise NoSuchKeyboardError('Could not find keymaps directory for: %s' % keyboard_name)
 
 
 def normpath(path):