[vcs] Merge DiffEditorTitleCustomizer getters to one which returns single class

Solution with 3 methods doesn't allow to calculate common data one time (like conflict type or current HEAD etc.)

GitOrigin-RevId: bbd2f61fdae1f5d0c7eba30ba359de8bf675a3d8

platform/vcs-api/src/com/intellij/openapi/vcs/merge/MergeDialogCustomizer.kt

@@ -15,6 +15,10 @@ import org.jetbrains.annotations.ApiStatus
  */
 @ApiStatus.OverrideOnly
 open class MergeDialogCustomizer {
+  companion object {
+    val DEFAULT_CUSTOMIZER_LIST = DiffEditorTitleCustomizerList(null, null, null)
+  }
+
   /**
    * Returns the description that is shown above the list of conflicted files.
    *
@@ -34,7 +38,7 @@ open class MergeDialogCustomizer {
    * Returns the title that is shown above the left panel in the 3-way merge dialog.
    *
    * @param file the file that is being merged.
-   * @see getLeftTitleCustomizer
+   * @see getTitleCustomizerList
    */
   open fun getLeftPanelTitle(file: VirtualFile): String = DiffBundle.message("merge.version.title.our")
 
@@ -42,7 +46,7 @@ open class MergeDialogCustomizer {
    * Returns the title that is shown above the center panel in the 3-way merge dialog.
    *
    * @param file the file that is being merged.
-   * @see getCenterTitleCustomizer
+   * @see getTitleCustomizerList
    */
   open fun getCenterPanelTitle(file: VirtualFile): String = DiffBundle.message("merge.version.title.base")
 
@@ -50,8 +54,8 @@ open class MergeDialogCustomizer {
    * Returns the title that is shown above the right panel in the 3-way merge dialog.
    *
    * @param file           the file that is being merged.
-   * @param revisionNumber the revision number of the file at the right. Can be `null` if unknown.
-   * @see getRightTitleCustomizer
+   * @param revisionNumber the revision number of the file at the right. Can be null if unknown.
+   * @see getTitleCustomizerList
    */
   open fun getRightPanelTitle(file: VirtualFile, revisionNumber: VcsRevisionNumber?): String =
     if (revisionNumber != null)
@@ -75,26 +79,16 @@ open class MergeDialogCustomizer {
   open fun getColumnNames(): List<String>? = null
 
   /**
-   * Allows to customize the left diff editor title in the 3-way merge dialog using [DiffEditorTitleCustomizer].
-   *
-   * This method takes precedence over [getLeftPanelTitle], which is used as a fallback only if this method returns `null`.
+   * Allows to customize diff editor titles in the 3-way merge dialog using [DiffEditorTitleCustomizer] for each editor.
+   * This method takes precedence over methods like [getLeftPanelTitle].
+   * If [DiffEditorTitleCustomizer] is null for the side, get(side)PanelTitle will be used as a fallback.
    */
   @ApiStatus.Experimental
-  open fun getLeftTitleCustomizer(file: FilePath): DiffEditorTitleCustomizer? = null
+  open fun getTitleCustomizerList(file: FilePath): DiffEditorTitleCustomizerList = DEFAULT_CUSTOMIZER_LIST
 
-  /**
-   * Allows to customize the center diff editor title in the 3-way merge dialog using [DiffEditorTitleCustomizer].
-   *
-   * This method takes precedence over [getCenterPanelTitle], which is used as a fallback only if this method returns `null`.
-   */
-  @ApiStatus.Experimental
-  open fun getCenterTitleCustomizer(file: FilePath): DiffEditorTitleCustomizer? = null
-
-  /**
-   * Allows to customize the right diff editor title in the 3-way merge dialog using [DiffEditorTitleCustomizer].
-   *
-   * This method takes precedence over [getRightPanelTitle], which is used as a fallback only if this method returns `null`.
-   */
-  @ApiStatus.Experimental
-  open fun getRightTitleCustomizer(file: FilePath): DiffEditorTitleCustomizer? = null
+  data class DiffEditorTitleCustomizerList(
+    val leftTitleCustomizer: DiffEditorTitleCustomizer?,
+    val centerTitleCustomizer: DiffEditorTitleCustomizer?,
+    val rightTitleCustomizer: DiffEditorTitleCustomizer?
+  )
 }

platform/vcs-impl/src/com/intellij/openapi/vcs/merge/MultipleFileMergeDialog.kt

@@ -3,7 +3,6 @@ package com.intellij.openapi.vcs.merge
 
 import com.intellij.CommonBundle
 import com.intellij.configurationStore.StoreReloadManager
-import com.intellij.diff.DiffEditorTitleCustomizer
 import com.intellij.diff.DiffManager
 import com.intellij.diff.DiffRequestFactory
 import com.intellij.diff.InvalidDiffRequestException
@@ -388,15 +387,7 @@ open class MultipleFileMergeDialog(
           }
 
           val filePath = VcsUtil.getFilePath(file)
-          val mergeTitleCustomizers = mergeDialogCustomizer.run {
-            listOf(
-              getLeftTitleCustomizer(filePath),
-              getCenterTitleCustomizer(filePath),
-              getRightTitleCustomizer(filePath)
-            )
-          }
-
-          ConflictData(mergeData, title, conflictTitles, mergeTitleCustomizers)
+          ConflictData(mergeData, title, conflictTitles, mergeDialogCustomizer.getTitleCustomizerList(filePath))
         }, "Loading Revisions...", true, project)
       }
       catch (ex: VcsException) {
@@ -442,7 +433,9 @@ open class MultipleFileMergeDialog(
         }
         break
       }
-      request.putUserData(EDITORS_TITLE_CUSTOMIZER, conflictData.contentTitleCustomizers)
+      conflictData.contentTitleCustomizers.run {
+        request.putUserData(EDITORS_TITLE_CUSTOMIZER, listOf(leftTitleCustomizer, centerTitleCustomizer, rightTitleCustomizer))
+      }
       DiffManager.getInstance().showMerge(project, request)
     }
     updateModelFromFiles()
@@ -470,6 +463,6 @@ open class MultipleFileMergeDialog(
     val mergeData: MergeData,
     val title: String,
     val contentTitles: List<String>,
-    val contentTitleCustomizers: List<DiffEditorTitleCustomizer?>
+    val contentTitleCustomizers: MergeDialogCustomizer.DiffEditorTitleCustomizerList
   )
 }

plugins/git4idea/src/git4idea/rebase/GitRebaseProcess.java

@@ -521,8 +521,17 @@ public class GitRebaseProcess {
                     GitMergeProvider.calcColumnName(true, myBasePresentable));
     }
 
-    @Nullable
+    @NotNull
     @Override
+    public DiffEditorTitleCustomizerList getTitleCustomizerList(@NotNull FilePath file) {
+      return new DiffEditorTitleCustomizerList(
+        getLeftTitleCustomizer(file),
+        null,
+        getRightTitleCustomizer(file)
+      );
+    }
+
+    @Nullable
     public DiffEditorTitleCustomizer getLeftTitleCustomizer(@NotNull FilePath file) {
       if (myIngoingCommit == null) {
         return null;
@@ -550,7 +559,6 @@ public class GitRebaseProcess {
     }
 
     @Nullable
-    @Override
     public DiffEditorTitleCustomizer getRightTitleCustomizer(@NotNull FilePath file) {
       if (myHead == null || myMergeBase == null || myUpstreamHash == null) {
         return null;