Fix not found error when reading empty hg repository

CHANGELOG.md

@@ -5,6 +5,10 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## Unreleased
+### Fixed
+- Not found error when using browse command in empty hg repository ([#1355](https://github.com/scm-manager/scm-manager/pull/1355))
+
 ## [2.6.0] - 2020-09-25
 ### Added
 - Add support for pr merge with prior rebase ([#1332](https://github.com/scm-manager/scm-manager/pull/1332))

scm-plugins/scm-hg-plugin/src/main/java/sonia/scm/repository/spi/javahg/HgFileviewCommandResultReader.java

@@ -87,8 +87,8 @@ class HgFileviewCommandResultReader {
     if (stack.isEmpty()) {
       // if the stack is empty, the requested path is probably a file
       return of(last);
-    } else if (stack.size() == 1 && stack.getFirst().isDirectory() && stack.getFirst().getChildren().isEmpty()) {
+    } else if (isEmptySubDirectory(stack)) {
-      // There are no empty directories in hg. When we get this,
+      // There are no empty directories in hg (except the root). When we get this,
       // we just get the requested path as a directory, but it does not exist.
       return empty();
     } else {
@@ -100,6 +100,16 @@ class HgFileviewCommandResultReader {
     }
   }
 
+  private boolean isEmptySubDirectory(Deque<FileObject> stack) {
+    if (stack.size() != 1) {
+      return false;
+    }
+    final FileObject singleEntry = stack.getFirst();
+    return singleEntry.isDirectory()
+      && singleEntry.getChildren().isEmpty()
+      && !singleEntry.getName().isEmpty();
+  }
+
   private FileObject read(HgInputStream stream) throws IOException {
     char type = (char) stream.read();
 

scm-plugins/scm-hg-plugin/src/test/java/sonia/scm/repository/spi/javahg/HgFileviewCommandResultReaderTest.java

@@ -269,6 +269,17 @@ class HgFileviewCommandResultReaderTest {
     assertThat(fileObject).isEmpty();
   }
 
+  @Test
+  void shouldReturnEmptyRootDir() throws IOException {
+    HgFileviewCommandResultReader reader = new MockInput()
+      .dir("")
+      .build();
+
+    Optional<FileObject> fileObject = reader.parseResult();
+
+    assertThat(fileObject).isNotEmpty();
+  }
+
   private HgInputStream createInputStream(String input) {
     return new HgInputStream(new ByteArrayInputStream(input.getBytes(UTF_8)), UTF_8.newDecoder());
   }