SONARPY-979 Rule S6326: Regular expressions should not contain multiple spaces (#1106)

Author: marco-bearzi-sonarsource

its/ruling/src/test/resources/expected/python-S6326.json

@@ -0,0 +1,35 @@
+{
+'project:biopython/Bio/PDB/parse_pdb_header.py':[
+38,
+39,
+295,
+296,
+],
+'project:biopython/Bio/PopGen/GenePop/Controller.py':[
+922,
+922,
+],
+'project:buildbot-0.8.6p1/buildbot/changes/mail.py':[
+478,
+],
+'project:numpy-1.16.4/numpy/distutils/from_template.py':[
+56,
+58,
+],
+'project:tensorflow/python/autograph/pyct/error_utils_test.py':[
+101,
+120,
+],
+'project:tensorflow/python/ops/map_fn.py':[
+648,
+],
+'project:tensorflow/tools/docs/parser.py':[
+590,
+],
+'project:tornado-2.3/demos/appengine/markdown.py':[
+1347,
+],
+'project:tornado-2.3/demos/blog/markdown.py':[
+1347,
+],
+}

python-checks/src/main/java/org/sonar/python/checks/CheckList.java

@@ -57,6 +57,7 @@
 import org.sonar.python.checks.regex.GraphemeClustersInClassesCheck;
 import org.sonar.python.checks.regex.ImpossibleBoundariesCheck;
 import org.sonar.python.checks.regex.InvalidRegexCheck;
+import org.sonar.python.checks.regex.MultipleWhitespaceCheck;
 import org.sonar.python.checks.regex.RedundantRegexAlternativesCheck;
 import org.sonar.python.checks.regex.RegexComplexityCheck;
 import org.sonar.python.checks.regex.RegexLookaheadCheck;
@@ -189,6 +190,7 @@ public static Iterable<Class> getChecks() {
       MissingNewlineAtEndOfFileCheck.class,
       ModifiedParameterValueCheck.class,
       ModuleNameCheck.class,
+      MultipleWhitespaceCheck.class,
       NeedlessPassCheck.class,
       NestedConditionalExpressionCheck.class,
       NestedControlFlowDepthCheck.class,

python-checks/src/main/java/org/sonar/python/checks/regex/MultipleWhitespaceCheck.java

@@ -0,0 +1,41 @@
+/*
+ * SonarQube Python Plugin
+ * Copyright (C) 2011-2022 SonarSource SA
+ * mailto:info AT sonarsource DOT com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.python.checks.regex;
+
+import java.util.Optional;
+import java.util.regex.Pattern;
+import org.sonar.check.Rule;
+import org.sonar.plugins.python.api.tree.CallExpression;
+import org.sonarsource.analyzer.commons.regex.RegexParseResult;
+import org.sonarsource.analyzer.commons.regex.finders.MultipleWhitespaceFinder;
+
+@Rule(key = "S6326")
+public class MultipleWhitespaceCheck extends AbstractRegexCheck {
+
+  @Override
+  public void checkRegex(RegexParseResult regexParseResult, CallExpression regexFunctionCall) {
+    Optional.ofNullable(regexFunctionCall.calleeSymbol())
+      .flatMap(symbol -> Optional.ofNullable(symbol.fullyQualifiedName()))
+      .filter(fqn -> lookedUpFunctions().containsKey(fqn))
+      .filter(fqn -> !regexParseResult.getResult().activeFlags().contains(Pattern.COMMENTS))
+      .ifPresent(fqn -> new MultipleWhitespaceFinder(this::addIssue).visit(regexParseResult));
+  }
+}
+

python-checks/src/main/resources/org/sonar/l10n/py/rules/python/S6326.html

@@ -0,0 +1,14 @@
+<p>Multiple spaces in a regular expression can make it hard to tell how many spaces should be matched. It’s more readable to use only one space and
+then indicate with a quantifier how many spaces are expected.</p>
+<h2>Noncompliant Code Example</h2>
+<pre>
+r"Hello,   world!"
+</pre>
+<h2>Compliant Solution</h2>
+<pre>
+r"Hello, {3}world!"
+</pre>
+<h2>Exceptions</h2>
+<p>If the extended modifier <code>re.X</code> or <code>re.VERBOSE</code> is set, whitespaces are ignored. In this case no issue should be triggered,
+because the whitespaces may be intended to improve readability.</p>
+

python-checks/src/main/resources/org/sonar/l10n/py/rules/python/S6326.json

@@ -0,0 +1,17 @@
+{
+  "title": "Regular expressions should not contain multiple spaces",
+  "type": "CODE_SMELL",
+  "status": "ready",
+  "remediation": {
+    "func": "Constant\/Issue",
+    "constantCost": "5min"
+  },
+  "tags": [
+    "regex"
+  ],
+  "defaultSeverity": "Major",
+  "ruleSpecification": "RSPEC-6326",
+  "sqKey": "S6326",
+  "scope": "Main",
+  "quickfix": "unknown"
+}

python-checks/src/main/resources/org/sonar/l10n/py/rules/python/Sonar_way_profile.json

@@ -152,6 +152,7 @@
     "S6002",
     "S6019",
     "S6323",
+    "S6326",
     "S6331",
     "S6035",
     "S6395",

python-checks/src/test/java/org/sonar/python/checks/regex/MultipleWhitespaceCheckTest.java

@@ -0,0 +1,33 @@
+/*
+ * SonarQube Python Plugin
+ * Copyright (C) 2011-2022 SonarSource SA
+ * mailto:info AT sonarsource DOT com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.python.checks.regex;
+
+import org.junit.Test;
+import org.sonar.python.checks.utils.PythonCheckVerifier;
+
+
+public class MultipleWhitespaceCheckTest {
+
+  @Test
+  public void test() {
+    PythonCheckVerifier.verify("src/test/resources/checks/regex/multipleWhitespaceCheck.py", new MultipleWhitespaceCheck());
+  }
+
+}

python-checks/src/test/resources/checks/regex/multipleWhitespaceCheck.py

@@ -0,0 +1,24 @@
+import re
+
+
+def non_compliant():
+    input = "Hello world!  Bob is a Bird... Bob is a Plane... Bob is Superman!"
+    changed = re.match(r"Hello,   world!", input)  # Noncompliant {{Replace spaces with quantifier `{3}`.}}
+    #                           ^^
+    changed = re.match(r"Hello,  world!", input)  # Noncompliant {{Replace spaces with quantifier `{2}`.}}
+    #                           ^
+    changed = re.match(r"Hello, world!     ", input)  # Noncompliant {{Replace spaces with quantifier `{5}`.}}
+    #                                  ^^^^
+    changed = re.match(r"Hello,      world!     ", input)  # Noncompliant 2
+
+
+def compliant():
+    input = "Hello world!  Bob is a Bird... Bob is a Plane... Bob is Superman!"
+    changed = re.match(r"\r\n|\r", input, re.MS)
+    changed = re.match(r"[   ]", input)
+    changed = re.compile(r"[   ]", re.X)
+    changed = re.match(r"Hello, world!\t\t\t\t", input)
+    changed = re.match(r"Hello , world!", input)
+    changed = re.match(r"'Hello, {3}world!'", input)
+    changed = re.match(r'Hello,     world!', flags=re.VERBOSE)
+    changed = re.compile(r'Hello,    world!', flags=re.X)