utils: checkstyle.py: Show location of coding style issue within line

The issue checkers display the line number and line content of each
offending line, but don't show the location of the issue within a line.
Improve checkstyle by adding a marker that points to the exact location.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

1 files changed, 26 insertions, 14 deletions

diff --git a/utils/checkstyle.py b/utils/checkstyle.py
index 77d6f390..4185c39a 100755
--- a/utils/checkstyle.py
+++ b/utils/checkstyle.py
@@ -556,8 +556,9 @@ class StyleChecker(metaclass=ClassRegistry):
 
 
 class StyleIssue(object):
-    def __init__(self, line_number, line, msg):
+    def __init__(self, line_number, position, line, msg):
         self.line_number = line_number
+        self.position = position
         self.line = line
         self.msg = msg
 
@@ -584,7 +585,7 @@ class HexValueChecker(StyleChecker):
             if value == value.lower():
                 continue
 
-            issues.append(StyleIssue(line_number, line,
+            issues.append(StyleIssue(line_number, match.span(0), line,
                                      f'Use lowercase hex constant {value.lower()}'))
 
         return issues
@@ -623,7 +624,7 @@ class IncludeChecker(StyleChecker):
                 header_type = 'C compatibility'
                 header = header[1:] + '.h'
 
-            issues.append(StyleIssue(line_number, line,
+            issues.append(StyleIssue(line_number, match.span(1), line,
                                      f'{header_type} header <{header}> is preferred'))
 
         return issues
@@ -641,10 +642,12 @@ class LogCategoryChecker(StyleChecker):
         issues = []
         for line_number in line_numbers:
             line = self.__content[line_number-1]
-            if not LogCategoryChecker.log_regex.search(line):
+            match = LogCategoryChecker.log_regex.search(line)
+            if not match:
                 continue
 
-            issues.append(StyleIssue(line_number, line, 'LOG() should use categories'))
+            issues.append(StyleIssue(line_number, match.span(1), line,
+                                     'LOG() should use categories'))
 
         return issues
 
@@ -660,8 +663,10 @@ class MesonChecker(StyleChecker):
         issues = []
         for line_number in line_numbers:
             line = self.__content[line_number-1]
-            if line.find('\t') != -1:
-                issues.append(StyleIssue(line_number, line, 'meson.build should use spaces for indentation'))
+            pos = line.find('\t')
+            if pos != -1:
+                issues.append(StyleIssue(line_number, [pos, pos], line,
+                                         'meson.build should use spaces for indentation'))
         return issues
 
 
@@ -681,7 +686,7 @@ class Pep8Checker(StyleChecker):
             ret = subprocess.run(['pycodestyle', '--ignore=E501', '-'],
                                  input=data, stdout=subprocess.PIPE)
         except FileNotFoundError:
-            issues.append(StyleIssue(0, None, 'Please install pycodestyle to validate python additions'))
+            issues.append(StyleIssue(0, None, None, 'Please install pycodestyle to validate python additions'))
             return issues
 
         results = ret.stdout.decode('utf-8').splitlines()
@@ -693,7 +698,7 @@ class Pep8Checker(StyleChecker):
 
             if line_number in line_numbers:
                 line = self.__content[line_number - 1]
-                issues.append(StyleIssue(line_number, line, msg))
+                issues.append(StyleIssue(line_number, None, line, msg))
 
         return issues
 
@@ -714,7 +719,7 @@ class ShellChecker(StyleChecker):
             ret = subprocess.run(['shellcheck', '-Cnever', '-'],
                                  input=data, stdout=subprocess.PIPE)
         except FileNotFoundError:
-            issues.append(StyleIssue(0, None, 'Please install shellcheck to validate shell script additions'))
+            issues.append(StyleIssue(0, None, None, 'Please install shellcheck to validate shell script additions'))
             return issues
 
         results = ret.stdout.decode('utf-8').splitlines()
@@ -727,11 +732,8 @@ class ShellChecker(StyleChecker):
             line = results[nr + 1]
             msg = results[nr + 2]
 
-            # Determined, but not yet used
-            position = msg.find('^') + 1
-
             if line_number in line_numbers:
-                issues.append(StyleIssue(line_number, line, msg))
+                issues.append(StyleIssue(line_number, None, line, msg))
 
         return issues
 
@@ -973,6 +975,16 @@ def check_file(top_level, commit, filename, checkers):
                 print('%s+%s%s' % (Colours.fg(Colours.Yellow), issue.line.rstrip(),
                                    Colours.reset()))
 
+                if issue.position is not None:
+                    # Align the position marker by using the original line with
+                    # all characters except for tabs replaced with spaces. This
+                    # ensures proper alignment regardless of how the code is
+                    # indented.
+                    start = issue.position[0]
+                    prefix = ''.join([c if c == '\t' else ' ' for c in issue.line[:start]])
+                    length = issue.position[1] - start - 1
+                    print(' ' + prefix + '^' + '~' * length)
+
     return len(formatted_diff) + len(issues)