[patch]: implement smart base root preselection and additional check that selected changes located under base dir path

platform/lvcs-impl/src/com/intellij/history/integration/ui/views/HistoryDialog.java

@@ -46,6 +46,7 @@ import com.intellij.openapi.ui.popup.JBPopupFactory;
 import com.intellij.openapi.util.*;
 import com.intellij.openapi.util.io.FileUtil;
 import com.intellij.openapi.vcs.VcsException;
+import com.intellij.openapi.vcs.changes.ChangesUtil;
 import com.intellij.openapi.vcs.changes.patch.CreatePatchConfigurationPanel;
 import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.openapi.wm.ex.IdeFocusTraversalPolicy;
@@ -455,6 +456,7 @@ public abstract class HistoryDialog<T extends HistoryDialogModel> extends FrameW
 
       CreatePatchConfigurationPanel p = new CreatePatchConfigurationPanel(myProject);
       p.setFileName(getDefaultPatchFile());
+      p.setCommonParentPath(ChangesUtil.findCommonAncestor(myModel.getChanges()));
       if (!showAsDialog(p)) return;
       myModel.createPatch(p.getFileName(), p.getBaseDirName(), p.isReversePatch());
 

platform/util/src/com/intellij/openapi/util/io/FileUtil.java

@@ -212,6 +212,15 @@ public class FileUtil extends FileUtilRt {
     return result;
   }
 
+  @Nullable
+  public static File findAncestor(@NotNull File f1, @NotNull File f2) {
+    File ancestor = f1;
+    while (ancestor != null && !isAncestor(ancestor, f2, false)) {
+      ancestor = ancestor.getParentFile();
+    }
+    return ancestor;
+  }
+
   @Nullable
   public static File getParentFile(@NotNull File file) {
     return FileUtilRt.getParentFile(file);

platform/vcs-api/src/com/intellij/openapi/vcs/changes/ChangesUtil.java

@@ -32,6 +32,7 @@ import com.intellij.openapi.vfs.VfsUtilCore;
 import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.pom.Navigatable;
 import com.intellij.util.NullableFunction;
+import com.intellij.util.ObjectUtils;
 import com.intellij.util.containers.ContainerUtil;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -466,4 +467,33 @@ public class ChangesUtil {
   public static String getDefaultChangeListName() {
     return VcsBundle.message("changes.default.changelist.name");
   }
+
+  /**
+   * Find common ancestor for changes (included both before and after files)
+   */
+  @Nullable
+  public static File findCommonAncestor(@NotNull Collection<Change> changes) {
+    File ancestor = null;
+    for (Change change : changes) {
+      File currentChangeAncestor = getCommonBeforeAfterAncestor(change);
+      if (currentChangeAncestor == null) return null;
+      if (ancestor == null) {
+        ancestor = currentChangeAncestor;
+      }
+      else {
+        ancestor = FileUtil.findAncestor(ancestor, currentChangeAncestor);
+        if (ancestor == null) return null;
+      }
+    }
+    return ancestor;
+  }
+
+  @Nullable
+  private static File getCommonBeforeAfterAncestor(@NotNull Change change) {
+    FilePath before = getBeforePath(change);
+    FilePath after = getAfterPath(change);
+    return before == null
+           ? ObjectUtils.assertNotNull(after).getIOFile()
+           : after == null ? before.getIOFile() : FileUtil.findAncestor(before.getIOFile(), after.getIOFile());
+  }
 }

platform/vcs-impl/src/com/intellij/openapi/vcs/changes/patch/CreatePatchCommitExecutor.java

@@ -33,13 +33,16 @@ import com.intellij.openapi.util.DefaultJDOMExternalizer;
 import com.intellij.openapi.util.InvalidDataException;
 import com.intellij.openapi.util.JDOMExternalizable;
 import com.intellij.openapi.util.WriteExternalException;
+import com.intellij.openapi.vcs.AbstractVcs;
 import com.intellij.openapi.vcs.VcsApplicationSettings;
 import com.intellij.openapi.vcs.VcsBundle;
 import com.intellij.openapi.vcs.VcsConfiguration;
 import com.intellij.openapi.vcs.changes.*;
 import com.intellij.openapi.vcs.changes.shelf.ShelveChangesManager;
 import com.intellij.openapi.vcs.changes.ui.SessionDialog;
+import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.util.WaitForProgressToShow;
+import com.intellij.vcsUtil.VcsUtil;
 import org.jdom.Element;
 import org.jetbrains.annotations.Nls;
 import org.jetbrains.annotations.NonNls;
@@ -50,6 +53,7 @@ import javax.swing.*;
 import java.io.File;
 import java.util.Collection;
 import java.util.List;
+import java.util.Set;
 
 public class CreatePatchCommitExecutor extends LocalCommitExecutor implements ProjectComponent, JDOMExternalizable {
   private static final Logger LOG = Logger.getInstance("#com.intellij.openapi.vcs.changes.patch.CreatePatchCommitExecutor");
@@ -136,6 +140,15 @@ public class CreatePatchCommitExecutor extends LocalCommitExecutor implements Pr
         }
       }
       myPanel.setFileName(ShelveChangesManager.suggestPatchName(myProject, commitMessage, new File(PATCH_PATH), null));
+      File commonAncestor = ChangesUtil.findCommonAncestor(changes);
+      myPanel.setCommonParentPath(commonAncestor);
+      Set<AbstractVcs> affectedVcses = ChangesUtil.getAffectedVcses(changes, myProject);
+      if (affectedVcses.size() == 1 && commonAncestor != null) {
+        VirtualFile vcsRoot = VcsUtil.getVcsRootFor(myProject, VcsUtil.getFilePath(commonAncestor));
+        if (vcsRoot != null) {
+          myPanel.selectBasePath(vcsRoot.getPath());
+        }
+      }
       myPanel.setReversePatch(false);
 
       JComponent panel = myPanel.getPanel();

platform/vcs-impl/src/com/intellij/openapi/vcs/changes/patch/CreatePatchConfigurationPanel.java

@@ -61,6 +61,7 @@ public class CreatePatchConfigurationPanel {
   private ComboBox<Charset> myEncoding;
   private JLabel myWarningLabel;
   private final Project myProject;
+  @Nullable private File myCommonParentPath;
 
   public CreatePatchConfigurationPanel(@NotNull final Project project) {
     myProject = project;
@@ -124,6 +125,10 @@ public class CreatePatchConfigurationPanel {
       .getPanel();
   }
 
+  public void setCommonParentPath(@Nullable File commonParentPath) {
+    myCommonParentPath = commonParentPath;
+  }
+
   private void checkExist() {
     myWarningLabel.setText(new File(getFileName()).exists() ? "File with the same name already exists" : "");
   }
@@ -163,6 +168,10 @@ public class CreatePatchConfigurationPanel {
     if (StringUtil.isEmptyOrSpaces(baseDirName)) return new ValidationInfo("Base path can't be empty!", myBasePathField);
     File baseFile = new File(baseDirName);
     if (!baseFile.exists()) return new ValidationInfo("Base dir doesn't exist", myBasePathField);
+    if (myCommonParentPath != null && !FileUtil.isAncestor(baseFile, myCommonParentPath, false)) {
+      return new ValidationInfo(String.format("Base path doesn't contain all selected changes (use %s)", myCommonParentPath.getPath()),
+                                myBasePathField);
+    }
     return null;
   }