Ignore .env folder in the .env Config provider

implementation/src/main/java/io/smallrye/config/AbstractLocationConfigSourceLoader.java

@@ -80,11 +80,11 @@ protected boolean failOnMissingFile() {
     protected abstract ConfigSource loadConfigSource(final URL url, final int ordinal) throws IOException;
 
     protected List<ConfigSource> loadConfigSources(final String location, final int ordinal) {
-        return loadConfigSources(new String[] { location }, ordinal);
+        return loadConfigSources(location != null ? new String[] { location } : null, ordinal);
     }
 
     protected List<ConfigSource> loadConfigSources(final String location, final int ordinal, final ClassLoader classLoader) {
-        return loadConfigSources(new String[] { location }, ordinal, classLoader);
+        return loadConfigSources(location != null ? new String[] { location } : null, ordinal, classLoader);
     }
 
     protected List<ConfigSource> loadConfigSources(final String[] locations, final int ordinal) {

implementation/src/main/java/io/smallrye/config/DotEnvConfigSourceProvider.java

@@ -2,6 +2,8 @@
 
 import java.io.IOException;
 import java.net.URL;
+import java.nio.file.Files;
+import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.HashMap;
 import java.util.List;
@@ -17,7 +19,7 @@ public class DotEnvConfigSourceProvider extends AbstractLocationConfigSourceLoad
     private final String location;
 
     public DotEnvConfigSourceProvider() {
-        this(Paths.get(System.getProperty("user.dir"), ".env").toUri().toString());
+        this(getDotEnvFile(".env"));
     }
 
     public DotEnvConfigSourceProvider(final String location) {
@@ -55,4 +57,9 @@ public static List<ConfigSource> dotEnvSources(final ClassLoader classLoader) {
     public static List<ConfigSource> dotEnvSources(final String location, final ClassLoader classLoader) {
         return new DotEnvConfigSourceProvider(location).getConfigSources(classLoader);
     }
+
+    private static String getDotEnvFile(final String filename) {
+        Path dotEnvFile = Paths.get(System.getProperty("user.dir"), filename);
+        return Files.isDirectory(dotEnvFile) ? null : dotEnvFile.toUri().toString();
+    }
 }

testsuite/extra/src/test/java/io/smallrye/config/test/location/DotEnvTest.java

@@ -0,0 +1,56 @@
+package io.smallrye.config.test.location;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+import java.io.FileOutputStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Properties;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import io.smallrye.config.DotEnvConfigSourceProvider;
+import io.smallrye.config.SmallRyeConfig;
+import io.smallrye.config.SmallRyeConfigBuilder;
+
+public class DotEnvTest {
+    @Test
+    void dotEnv(@TempDir Path tempDir) throws Exception {
+        Properties dotEnv = new Properties();
+        dotEnv.setProperty("FOO_BAR", "value");
+        try (FileOutputStream out = new FileOutputStream(tempDir.resolve(".env").toFile())) {
+            dotEnv.store(out, null);
+        }
+
+        String previousUserDir = System.getProperty("user.dir");
+        System.setProperty("user.dir", tempDir.toString());
+
+        SmallRyeConfig config = new SmallRyeConfigBuilder()
+                .withSources(new DotEnvConfigSourceProvider())
+                .build();
+
+        assertEquals("value", config.getRawValue("foo.bar"));
+
+        System.setProperty("user.dir", previousUserDir);
+    }
+
+    @Test
+    void dotEnvFolder(@TempDir Path tempDir) throws Exception {
+        Path dotEnvFolder = tempDir.resolve(".env");
+        Files.createDirectories(dotEnvFolder);
+        Files.createDirectories(dotEnvFolder.resolve("foo"));
+
+        String previousUserDir = System.getProperty("user.dir");
+        System.setProperty("user.dir", tempDir.toString());
+
+        SmallRyeConfig config = new SmallRyeConfigBuilder()
+                .withSources(new DotEnvConfigSourceProvider())
+                .build();
+
+        assertNull(config.getRawValue("foo.bar"));
+
+        System.setProperty("user.dir", previousUserDir);
+    }
+}