Create a skylint and buildozer checker for preventing glob(**/*.java)

For now we will only block Java recursive globs. Any other languages or
extensions can be banned relatively easily.

RELNOTES:
Add lint check for discouraging glob(["**/*.java"])
PiperOrigin-RevId: 185417760

2 files changed, 134 insertions, 0 deletions

diff --git a/src/tools/skylark/java/com/google/devtools/skylark/skylint/Linter.java b/src/tools/skylark/java/com/google/devtools/skylark/skylint/Linter.java
index 3f4f54467f..3334dcae27 100644
--- a/src/tools/skylark/java/com/google/devtools/skylark/skylint/Linter.java
+++ b/src/tools/skylark/java/com/google/devtools/skylark/skylint/Linter.java
@@ -45,6 +45,7 @@ public class Linter {
           .put("naming", NamingConventionsChecker::check)
           .put("no-effect", StatementWithoutEffectChecker::check)
           .put("usage", UsageChecker::check)
+          .put("bad-recursive-glob", NativeRecursiveGlobChecker::check)
           .build();
   /** Map of all multi-file checks and their names. */
   private static final ImmutableMap<String, MultiFileCheck> nameToMultiFileCheck =
diff --git a/src/tools/skylark/java/com/google/devtools/skylark/skylint/NativeRecursiveGlobChecker.java b/src/tools/skylark/java/com/google/devtools/skylark/skylint/NativeRecursiveGlobChecker.java
new file mode 100644
index 0000000000..0f8fe26d93
--- /dev/null
+++ b/src/tools/skylark/java/com/google/devtools/skylark/skylint/NativeRecursiveGlobChecker.java
@@ -0,0 +1,133 @@
+// Copyright 2017 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.devtools.skylark.skylint;
+
+import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Iterables;
+import com.google.devtools.build.lib.syntax.Argument;
+import com.google.devtools.build.lib.syntax.AssignmentStatement;
+import com.google.devtools.build.lib.syntax.BuildFileAST;
+import com.google.devtools.build.lib.syntax.Expression;
+import com.google.devtools.build.lib.syntax.FuncallExpression;
+import com.google.devtools.build.lib.syntax.Identifier;
+import com.google.devtools.build.lib.syntax.ListLiteral;
+import com.google.devtools.build.lib.syntax.StringLiteral;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * Checks the adherence to Skylark best practices for recursive globs.
+ *
+ * <p>Recursive globs should be used sparingly and not for files containing source code. This check
+ * flags incorrect usage of recurisive globs, for languages known to be problematic.
+ */
+public class NativeRecursiveGlobChecker extends AstVisitorWithNameResolution {
+
+  /* List of instances of glob(**) we found. */
+  private final List<Issue> issues = new ArrayList<>();
+
+  /* List of known variables we've encountered for finding indirect use of glob(**) */
+  private final Map<Identifier, Expression> vars = new HashMap<>();
+
+  /* List of variables that were found in globs, but had not yet been resolved in SkyLark
+   * processing.  Example:
+   *
+   * native.glob([my_var])
+   *
+   * ...
+   *
+   * my_var = "**\/*.java"
+   */
+  private final Set<Identifier> waitingFor = new HashSet<>();
+
+  private static final String BAD_RECURSIVE_GLOB = "bad-recursive-glob";
+
+  public static List<Issue> check(BuildFileAST ast) {
+    NativeRecursiveGlobChecker checker = new NativeRecursiveGlobChecker();
+    checker.visit(ast);
+    return checker.issues;
+  }
+
+  private void evaluateInclude(Expression exp) {
+    if (exp.kind() == Expression.Kind.STRING_LITERAL) {
+      StringLiteral str = (StringLiteral) exp;
+      String value = str.getValue();
+      if (value.contains("**") && value.endsWith("*.java")) {
+        issues.add(
+            Issue.create(
+                BAD_RECURSIVE_GLOB,
+                "go/build-style#globs "
+                + "Do not use recursive globs for Java source files. glob() on "
+                + "multiple directories is error prone, it can lead to import "
+                + "cycles between Java packages that are hard to break.",
+                exp.getLocation()));
+      }
+    } else if (exp.kind() == Expression.Kind.IDENTIFIER) {
+      Identifier id = (Identifier) exp;
+      if (vars.containsKey(id)) {
+        evaluateInclude(vars.get(id));
+      } else {
+        waitingFor.add(id);
+      }
+    }
+  }
+
+  @Override
+  public void visit(FuncallExpression node) {
+    if (node.getFunction().toString().equals("glob")) {
+      Argument.Passed include = null;
+      int index = 0;
+      List<Argument.Passed> args = node.getArguments();
+      for (Argument.Passed a : args) {
+        if (index == 0 && a.isPositional()) {
+          include = a;
+          break;
+        } else if (index > 1
+            && a.isKeyword()
+            && (a.getName() != null && a.getName().equals("include"))) {
+          include = a;
+          break;
+        }
+        index++;
+      }
+      if (include != null && include.getValue().kind() == Expression.Kind.LIST_LITERAL) {
+        ListLiteral list = (ListLiteral) include.getValue();
+        for (Expression exp : list.getElements()) {
+          evaluateInclude(exp);
+        }
+      }
+    }
+    super.visit(node);
+  }
+
+  @Override
+  public void visit(AssignmentStatement node) {
+    super.visit(node);
+    ImmutableSet<Identifier> lvalues = node.getLValue().boundIdentifiers();
+    if (lvalues.size() != 1) {
+      return;
+    }
+    Identifier ident = Iterables.getOnlyElement(lvalues);
+    vars.put(ident, node.getExpression());
+
+    if (waitingFor.contains(ident)) {
+      evaluateInclude(node.getExpression());
+    }
+  }
+}