git: IDEA-101222 read branch files in UTF-8

Man git-commit-tree:
    Path names are encoded in UTF-8 normalization form C.
    This applies to tree objects, the index file, ref names,
    as well as path names in command line arguments,
    environment variables and config files.

platform/dvcs-impl/src/com/intellij/dvcs/DvcsUtil.java

@@ -241,10 +241,15 @@ public class DvcsUtil {
    */
   @NotNull
   public static String tryLoadFile(@NotNull final File file) throws RepoStateException {
+    return tryLoadFile(file, null);
+  }
+
+  @NotNull
+  public static String tryLoadFile(@NotNull final File file, @Nullable String encoding) throws RepoStateException {
     return tryOrThrow(new Callable<String>() {
       @Override
       public String call() throws Exception {
-        return StringUtil.convertLineSeparators(FileUtil.loadFile(file)).trim();
+        return StringUtil.convertLineSeparators(FileUtil.loadFile(file, encoding)).trim();
       }
     }, file);
   }
@@ -252,8 +257,14 @@ public class DvcsUtil {
   @Nullable
   @Contract("_ , !null -> !null")
   public static String tryLoadFileOrReturn(@NotNull final File file, @Nullable String defaultValue) {
+    return tryLoadFileOrReturn(file, defaultValue, null);
+  }
+
+  @Nullable
+  @Contract("_ , !null, _ -> !null")
+  public static String tryLoadFileOrReturn(@NotNull final File file, @Nullable String defaultValue, @Nullable String encoding) {
     try {
-      return tryLoadFile(file);
+      return tryLoadFile(file, encoding);
     }
     catch (RepoStateException e) {
       LOG.error(e);

plugins/git4idea/src/git4idea/GitUtil.java

@@ -37,6 +37,7 @@ import com.intellij.openapi.vcs.changes.ChangeListManager;
 import com.intellij.openapi.vcs.changes.ChangeListManagerEx;
 import com.intellij.openapi.vcs.versionBrowser.CommittedChangeList;
 import com.intellij.openapi.vcs.vfs.AbstractVcsVirtualFile;
+import com.intellij.openapi.vfs.CharsetToolkit;
 import com.intellij.openapi.vfs.LocalFileSystem;
 import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.util.Consumer;
@@ -52,7 +53,10 @@ import git4idea.changes.GitCommittedChangeList;
 import git4idea.commands.*;
 import git4idea.config.GitConfigUtil;
 import git4idea.i18n.GitBundle;
-import git4idea.repo.*;
+import git4idea.repo.GitBranchTrackInfo;
+import git4idea.repo.GitRemote;
+import git4idea.repo.GitRepository;
+import git4idea.repo.GitRepositoryManager;
 import git4idea.util.GitSimplePathsBrowser;
 import git4idea.util.GitUIUtil;
 import git4idea.util.StringScanner;
@@ -112,7 +116,7 @@ public class GitUtil {
       return headExists ? dotGit : null;
     }
 
-    String content = DvcsUtil.tryLoadFileOrReturn(dotGit, null);
+    String content = DvcsUtil.tryLoadFileOrReturn(dotGit, null, CharsetToolkit.UTF8);
     if (content == null) return null;
     String pathToDir = parsePathToRepository(content);
     return findSubmoduleRepositoryDir(rootDir.getPath(), pathToDir);

plugins/git4idea/src/git4idea/repo/GitRepositoryReader.java

@@ -23,6 +23,7 @@ import com.intellij.openapi.util.Condition;
 import com.intellij.openapi.util.Pair;
 import com.intellij.openapi.util.io.FileUtil;
 import com.intellij.openapi.util.text.LineTokenizer;
+import com.intellij.openapi.vfs.CharsetToolkit;
 import com.intellij.util.Function;
 import com.intellij.util.Processor;
 import com.intellij.util.containers.ContainerUtil;
@@ -169,7 +170,7 @@ class GitRepositoryReader {
     if (rebaseDir.exists()) {
       File headName = new File(rebaseDir, "head-name");
       if (headName.exists()) {
-        return DvcsUtil.tryLoadFileOrReturn(headName, null);
+        return DvcsUtil.tryLoadFileOrReturn(headName, null, CharsetToolkit.UTF8);
       }
     }
     return null;
@@ -197,7 +198,7 @@ class GitRepositoryReader {
       return Collections.emptyMap();
     }
     try {
-      String content = DvcsUtil.tryLoadFile(myPackedRefsFile);
+      String content = DvcsUtil.tryLoadFile(myPackedRefsFile, CharsetToolkit.UTF8);
       return ContainerUtil.map2MapNotNull(LineTokenizer.tokenize(content, false), new Function<String, Pair<String, String>>() {
         @Override
         public Pair<String, String> fun(String line) {
@@ -319,7 +320,7 @@ class GitRepositoryReader {
   private HeadInfo readHead() {
     String headContent;
     try {
-      headContent = DvcsUtil.tryLoadFile(myHeadFile);
+      headContent = DvcsUtil.tryLoadFile(myHeadFile, CharsetToolkit.UTF8);
     }
     catch (RepoStateException e) {
       LOG.error(e);

plugins/git4idea/tests/git4idea/repo/GitRepositoryReaderNewTest.kt

@@ -111,6 +111,14 @@ class GitRepositoryReaderNewTest : GitSingleRepoTest() {
     assertEquals("Fresh repository should be on master", "master", currentBranch!!.name)
   }
 
+  fun `test non-ascii current branch name`() {
+    makeCommit("file.txt")
+    val branch = "teslá"
+    git("checkout -b $branch")
+    val state = readState()
+    assertEquals(branch, state.currentBranch!!.name)
+  }
+
   private fun moveToDetachedHead(): String {
     makeCommit("file.txt")
     makeCommit("file.txt")