[lint] Identify mismatched clang-format-{on,off} comments (RobotLocom…

…otion#20396)

common/symbolic/expression/test/substitution_test.cc

@@ -329,10 +329,8 @@ TEST_F(SymbolicSubstitutionTest, CheckHomomorphismFormulaVarExpr) {
   fns.push_back([&](const Expression& x) { return !fns[15](x); });
   fns.push_back([&](const Expression& x) {
     Eigen::Matrix<Expression, 2, 2> m;
-    // clang-format off
     m << (x * y_), 2.0,
               2.0, (x * y_);
-    // clang-format on
     return positive_semidefinite(m);
   });
   // clang-format on

geometry/optimization/test/affine_subspace_test.cc

@@ -1073,7 +1073,7 @@ GTEST_TEST(AffineSubspaceTest, EqualityTest) {
   basis1 << 1, 0,
             0, 1,
             0, 0;
-  // clang- format on
+  // clang-format on
   Eigen::VectorXd translation1(3);
   translation1 << 0, 0, 1;
 
@@ -1112,13 +1112,13 @@ GTEST_TEST(AffineSubspaceTest, EqualityTest2) {
   basis1 << -1,  0.5,
             0.5, -1,
             0.5, 0.5;
-  // clang- format on
+  // clang-format on
   Eigen::Matrix<double, 3, 2> basis2;
   // clang-format off
   basis2 << 1,  0,
             -1, 1,
             0, -1;
-  // clang- format on
+  // clang-format on
   Eigen::VectorXd translation1(3);
   translation1 << 0, 0, 1;
   Eigen::VectorXd translation2(3);

geometry/optimization/test/hpolyhedron_test.cc

@@ -859,7 +859,6 @@ GTEST_TEST(HPolyhedronTest, IrredundantBallIntersectionContainsBothOriginal) {
   HPolyhedron L1_ball = HPolyhedron::MakeL1Ball(3);
   HPolyhedron Linfty_ball = HPolyhedron::MakeUnitBox(3);
 
-  // clang-format on
   HPolyhedron IrredL1intoLinf = Linfty_ball.Intersection(L1_ball, true);
   HPolyhedron IrredLinfintoL1 = L1_ball.Intersection(Linfty_ball, true);
 
@@ -905,7 +904,7 @@ GTEST_TEST(HPolyhedronTest, ReduceToInfeasibleSet) {
        0, 1, -1,
        0, 0, -1;
   b << 1, -1, -1, -1, 0;
-  // clang-format off
+  // clang-format on
 
   HPolyhedron H{A, b};
   HPolyhedron H_reduced = H.ReduceInequalities();
@@ -938,9 +937,9 @@ GTEST_TEST(HPolyhedronTest, IsEmptyNonMinimalInequalitySet) {
        0, 0, -1,
        1, -1, 0,
        -1, 0, 1,
-       0, 1, -1;;
-  b << 1, 0, -1, -1, -1;;
-  // clang-format off
+       0, 1, -1;
+  b << 1, 0, -1, -1, -1;
+  // clang-format on
 
   HPolyhedron H{A, b};
   EXPECT_TRUE(H.IsEmpty());
@@ -960,8 +959,6 @@ GTEST_TEST(HPolyhedronTest, IsEmptyBoundedHPolyhedron) {
   EXPECT_FALSE(H.IsEmpty());
 }
 
-
-
 GTEST_TEST(HPolyhedronTest, IntersectionTest) {
   HPolyhedron H_A = HPolyhedron::MakeUnitBox(2);
   HPolyhedron H_B = HPolyhedron::MakeBox(Vector2d(0, 0), Vector2d(2, 2));

geometry/optimization/test/intersection_test.cc

@@ -256,7 +256,7 @@ GTEST_TEST(IntersectionTest, EmptyIntersectionTest1) {
        0, 1, -1,
        0, 0, -1;
   b << 1, -1, -1, -1, 0;
-  // clang-format off
+  // clang-format on
 
   HPolyhedron H1{A, b};
   const Point P1(Vector3d{0.1, 1.2, 0.3});

solvers/test/complementary_problem_test.cc

@@ -77,7 +77,7 @@ GTEST_TEST(TestComplementaryProblem, flp2) {
        0, 0, 0, 0,
        8.0 / 3, 2, 2, 8.0/3,
        2, 5.0/4, 5.0/4, 2;
-  // clang-format off;
+  // clang-format on
   Eigen::Vector4d q(0, 0, -36, -25);
   prog.AddLinearComplementarityConstraint(M, q, {x, y});
   prog.AddBoundingBoxConstraint(0, 10, x);

solvers/test/mathematical_program_test.cc

@@ -2666,9 +2666,7 @@ TEST_F(SymbolicLorentzConeTest, Test3) {
   // [               x(2)]
   // [  -x(1)            ]
   Matrix<Expression, 4, 1> e;
-  // clang-format on
   e << 2 * x_(0) + 3 * x_(2), -x_(0) + 2 * x_(2), +x_(2), -x_(1);
-  // clang-format off;
   CheckParsedSymbolicLorentzConeConstraint(&prog_, e);
 }
 

systems/controllers/test/linear_quadratic_regulator_test.cc

@@ -248,9 +248,7 @@ GTEST_TEST(TestLqr, ConstrainedLinearSystem) {
        3, 10;
   // clang-format on
   Eigen::Matrix<double, 3, 2> N;
-  // clang-format on
   N << 1, 0.5, 0.5, -1, 0, 1;
-  // clang-format off
 
   TestLqrWithHjb(A, B, Q, R);
   TestLqrWithHjb(A, B, Q, R, N);

tools/lint/drakelint.py

@@ -159,6 +159,46 @@ def _check_iostream(filename):
     return 1
 
 
+def _check_clang_format_toggles(filename):
+    """Checks that clang-format-{off,on} are correctly paired up.
+    """
+    # These are the needles we'll be looking for.
+    offs = [
+        "// clang-format off\n",
+        "// clang-format off ",
+        "/* clang-format off */",
+        "/* clang-format off to disable clang-format-includes */"
+    ]
+    ons = [
+        "// clang-format on\n",
+        "// clang-format on ",
+        "/* clang-format on */",
+    ]
+
+    with open(filename, mode='r', encoding='utf-8') as file:
+        lines = file.readlines()
+    enabled = True
+    num_errors = 0
+    for i, line in enumerate(lines):
+        line = line + "\n"
+        found_on = any([x in line for x in ons])
+        found_off = any([x in line for x in offs])
+        if found_on:
+            if enabled:
+                print(f"ERROR: {filename}:{i + 1}: "
+                      "This line is redundant; clang-format is already on")
+                num_errors += 1
+            enabled = True
+        if found_off:
+            if not enabled:
+                print(f"ERROR: {filename}:{i + 1}: "
+                      "This line is redundant; clang-format is already off")
+                num_errors += 1
+            enabled = False
+
+    return num_errors
+
+
 def main():
     """Run Drake lint checks on each path specified as a command-line argument.
     Exit 1 if any of the paths are invalid or any lint checks fail.
@@ -182,6 +222,7 @@ def main():
             total_errors += _check_includes(filename)
             total_errors += _check_unguarded_openmp_uses(filename)
             total_errors += _check_iostream(filename)
+            total_errors += _check_clang_format_toggles(filename)
 
     if total_errors == 0:
         sys.exit(0)