Update CODEOWNERS parser to not log errors on comments with leading whitespace (#8349)

Author: nikita-tkachenko-datadog

dd-java-agent/agent-ci-visibility/src/main/java/datadog/trace/civisibility/codeowners/EntryBuilder.java

@@ -47,9 +47,14 @@ public EntryBuilder(CharacterMatcher.Factory characterMatcherFactory, String s)
 
   public @Nullable Entry parse() {
     try {
-      if (c.length == 0 // empty line
-          || c[0] == '#' // comment
-          || c[0] == '[') { // section header
+      // skip trailing whitespace
+      while (offset < c.length && Character.isWhitespace(c[offset])) {
+        offset++;
+      }
+
+      if (offset == c.length // empty line
+          || c[offset] == '#' // comment
+          || c[offset] == '[') { // section header
         return null;
       }
 

dd-java-agent/agent-ci-visibility/src/test/groovy/datadog/trace/civisibility/codeowners/EntryBuilderTest.groovy

@@ -154,14 +154,25 @@ class EntryBuilderTest extends Specification {
     return result.toString()
   }
 
-  def "test invalid range parsing"() {
+  def "test invalid entry parsing: #entry"() {
     setup:
     def matcherFactory = new CharacterMatcher.Factory()
 
     when:
-    def entry = new EntryBuilder(matcherFactory, "token[z-a] owner").parse()
+    def parsedEntry = new EntryBuilder(matcherFactory, entry).parse()
 
     then:
-    entry == null
+    parsedEntry == null
+
+    where:
+    entry << [
+      "token[z-a] owner",
+      "# comment",
+      " # comment with a leading space",
+      "[section header]",
+      " [section header with a leading space]",
+      "",
+      " ",
+    ]
   }
 }