Introduce two FileRules Refaster rules (#1596)

Invoking `File#mkdirs` before testing for existence of the specified
path, rather than the other way around, avoids a subtle concurrency
issue.

See also openrewrite/rewrite#5189.

error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/FileRules.java

@@ -4,6 +4,7 @@ import static java.nio.charset.StandardCharsets.UTF_8;
 
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
+import com.google.errorprone.refaster.annotation.AlsoNegation;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
 import com.google.errorprone.refaster.annotation.Repeated;
 import java.io.File;
@@ -11,6 +12,7 @@ import java.io.IOException;
 import java.net.URI;
 import java.nio.charset.Charset;
 import java.nio.file.Files;
+import java.nio.file.LinkOption;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.nio.file.attribute.FileAttribute;
@@ -141,4 +143,35 @@ final class FileRules {
       return Files.createTempFile(directory.toPath(), prefix, suffix).toFile();
     }
   }
+
+  /**
+   * Invoke {@link File#mkdirs()} before {@link Files#exists(Path, LinkOption...)} to avoid
+   * concurrency issues.
+   */
+  static final class PathToFileMkDirsFilesExists {
+    @BeforeTemplate
+    boolean before(Path path) {
+      return Files.exists(path) || path.toFile().mkdirs();
+    }
+
+    @AfterTemplate
+    @AlsoNegation
+    boolean after(Path path) {
+      return path.toFile().mkdirs() || Files.exists(path);
+    }
+  }
+
+  /** Invoke {@link File#mkdirs()} before {@link File#exists()} to avoid concurrency issues. */
+  static final class FileMkDirsFileExists {
+    @BeforeTemplate
+    boolean before(File file) {
+      return file.exists() || file.mkdirs();
+    }
+
+    @AfterTemplate
+    @AlsoNegation
+    boolean after(File file) {
+      return file.mkdirs() || file.exists();
+    }
+  }
 }

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/FileRulesTestInput.java

@@ -39,4 +39,16 @@ final class FileRulesTest implements RefasterRuleCollectionTestCase {
   File testFilesCreateTempFileInCustomDirectoryToFile() throws IOException {
     return File.createTempFile("foo", "bar", new File("baz"));
   }
+
+  ImmutableSet<Boolean> testPathToFileMkDirsFilesExists() {
+    return ImmutableSet.of(
+        Files.exists(Path.of("foo")) || Path.of("foo").toFile().mkdirs(),
+        !Files.exists(Path.of("bar")) && !Path.of("bar").toFile().mkdirs());
+  }
+
+  ImmutableSet<Boolean> testFileMkDirsFileExists() {
+    return ImmutableSet.of(
+        new File("foo").exists() || new File("foo").mkdirs(),
+        !new File("bar").exists() && !new File("bar").mkdirs());
+  }
 }

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/FileRulesTestOutput.java

@@ -39,4 +39,16 @@ final class FileRulesTest implements RefasterRuleCollectionTestCase {
   File testFilesCreateTempFileInCustomDirectoryToFile() throws IOException {
     return Files.createTempFile(new File("baz").toPath(), "foo", "bar").toFile();
   }
+
+  ImmutableSet<Boolean> testPathToFileMkDirsFilesExists() {
+    return ImmutableSet.of(
+        Path.of("foo").toFile().mkdirs() || Files.exists(Path.of("foo")),
+        !Path.of("bar").toFile().mkdirs() && !Files.exists(Path.of("bar")));
+  }
+
+  ImmutableSet<Boolean> testFileMkDirsFileExists() {
+    return ImmutableSet.of(
+        new File("foo").mkdirs() || new File("foo").exists(),
+        !new File("bar").mkdirs() && !new File("bar").exists());
+  }
 }