[FEATURE] Check `git.mergeEditor` before opening conflicts

[OldStarchy]

1. Background

If there's conflicts in the work tree, GG+ shows a header "Rebase Conflict (0/1 Resolved)" and a list of conflicting files.
When you click on one it opens the merge editor. I don't like the merge editor and instead prefer to edit the file manually with the merge.conflictStyle diff3 config.

VSCode has an option git.mergeEditor: boolean that controls the action when opening conflicting files from the native source view true => opens in the new merge editor false => opens the file in a normal text editor.

2. Proposed Solution

Please check and follow the git.mergeEditor preference when opening conflicted files from that list.

3. Affected Area

Check all that apply.

• Commit graph (Graph View)
• Commit details panel (Bottom Panel)
• Sidebar (Branches / Remotes / Tags / Stashes / Worktrees)
• Toolbar (Fetch / Pull / Push / Refresh)
• Context menu
• Search
• Statistics view (Stats)
• Activity Log
• i18n (localization)
• Git operations (new Git command support)
• Other

4. Alternatives or References

Currently, this view of GG+ doesn't have much over the native file list in source control, so I'll continue using that.

The native functionality is fairly basic though, and e.g. lacks a git rebase --abort button that GG+ provides. I think there's plenty of room to make GG+ more useful than the native interface.

[OldStarchy]

This sort-of solves the problem, except the behavior is still different to native in the case of a Modified by us, deleted by them conflict, this code opens a diff editor that just says "File not found" where the native button opens the 3-way merge editor with an empty output.

diff --git a/src/panels/MainPanel.ts b/src/panels/MainPanel.ts
index 5869905..67db1df 100644
--- a/src/panels/MainPanel.ts
+++ b/src/panels/MainPanel.ts
@@ -1565,10 +1565,16 @@ export class MainPanel {
         case 'openConflictFile': {
           const fullPath = this.resolveRepoRelativePath(message.payload.file, 'openConflictFile');
           const fileUri = vscode.Uri.file(fullPath);
-          // Try to open in VS Code's 3-way merge editor, fallback to normal editor
-          try {
-            await vscode.commands.executeCommand('git.openMergeEditor', fileUri);
-          } catch {
+          const useMergeEditor = vscode.workspace.getConfiguration().get('git.mergeEditor');
+
+          if (useMergeEditor) {
+            // Try to open in VS Code's 3-way merge editor, fallback to normal editor
+            try {
+              await vscode.commands.executeCommand('git.openMergeEditor', fileUri);
+            } catch {
+              await vscode.window.showTextDocument(fileUri);
+            }
+          } else {
             await vscode.window.showTextDocument(fileUri);
           }
           break;