Fetch three-way-diff content for merge conflicts (#896)

- [WIP] console logs content
- TODO: display diff

Author: navn-r

jupyterlab_git/git.py

@@ -1173,6 +1173,38 @@ async def _get_tag(self, path, commit_sha):
                 )
             )
 
+    async def show_from_object(self, ref, path):
+        """
+        Execute git show <ref> command & return the result.
+        """
+        command = ["git", "show", ref]
+
+        code, output, error = await execute(command, cwd=path)
+
+        error_messages = map(
+            lambda n: n.lower(),
+            [
+                "fatal: Object '{}' exists on disk, but not here".format(ref),
+                "fatal: Object '{}' does not exist (neither on disk nor in the index)".format(
+                    ref
+                ),
+                # TODO fix this
+                "fatal: Object '{}' does not exist in 'HEAD'".format(ref),
+                "fatal: Invalid object name 'HEAD'",
+            ],
+        )
+        lower_error = error.lower()
+        if code == 0:
+            return output
+        elif any([msg in lower_error for msg in error_messages]):
+            return ""
+        else:
+            raise tornado.web.HTTPError(
+                log_message="Error [{}] occurred while executing [{}] command to retrieve plaintext diff.".format(
+                    error, " ".join(command)
+                )
+            )
+
     async def show(self, filename, ref, path):
         """
         Execute git show <ref:filename> command & return the result.
@@ -1448,3 +1480,32 @@ async def tag_checkout(self, path, tag):
                 "command": " ".join(command),
                 "message": error,
             }
+
+    async def get_unmerged_file_contents(self, filename, path):
+        """
+        Returns the three-way-diff contents of an unmerged file
+
+        Execute `git ls-files -uz <filename>` command & return the file contents
+        Of the three object refs.
+
+        Args:
+            filename (str): Filename (relative to the git repository)
+            path (str): Git repository filepath
+        """
+        command = ["git", "ls-files", "-u", "-z", filename]
+
+        code, output, error = await execute(command, cwd=path)
+        if code != 0:
+            return {
+                "code": code,
+                "command": " ".join(command),
+                "message": error,
+            }
+
+        result = []
+        line_iterable = iter(strip_and_split(output))
+        for line in line_iterable:
+            ref = line.split(" ")[1]
+            content = await self.show_from_object(ref, path)
+            result.append(content)
+        return {"code": code, "contents": result}

jupyterlab_git/handlers.py

@@ -805,6 +805,22 @@ async def post(self, path: str = ""):
         self.finish(json.dumps(result))
 
 
+class GitMergeDiffHandler(GitHandler):
+    """
+    Handler to show a 3-way diff of a file with merge conflicts.
+    """
+
+    @tornado.web.authenticated
+    async def post(self, path: str = ""):
+        data = self.get_json_body()
+        filename = data["filename"]
+        response = await self.git.get_unmerged_file_contents(
+            filename,
+            self.url2localpath(path),
+        )
+        self.finish(json.dumps(response))
+
+
 def setup_handlers(web_app):
     """
     Setups all of the git command handlers.
@@ -842,6 +858,7 @@ def setup_handlers(web_app):
         ("/tags", GitTagHandler),
         ("/tag_checkout", GitTagCheckoutHandler),
         ("/add", GitAddHandler),
+        ("/merge_diff", GitMergeDiffHandler),
     ]
 
     handlers = [

src/commandsAndMenu.tsx

@@ -562,16 +562,6 @@ export function addCommands(
       for (const file of files) {
         const { context, filePath, isText, status } = file;
 
-        // Merge conflict
-        // TODO: handle
-        if (status === 'unmerged') {
-          logger.log({
-            message: 'File has conflicts!',
-            level: Level.ERROR
-          });
-          continue;
-        }
-
         // nothing to compare to for untracked files
         if (status === 'untracked') {
           continue;
@@ -580,6 +570,14 @@ export function addCommands(
         const repositoryPath = gitModel.getRelativeFilePath();
         const filename = PathExt.join(repositoryPath, filePath);
 
+        // Merge conflict
+        if (status === 'unmerged') {
+          const t = await gitModel.getMergeDiff(filename);
+          // TODO: handle
+          console.log(t);
+          continue;
+        }
+
         let diffContext = context;
         if (!diffContext) {
           const specialRef =

src/components/FileList.tsx

@@ -363,7 +363,7 @@ export class FileList extends React.Component<IFileListProps, IFileListState> {
     return (
       <FileItem
         trans={this.props.trans}
-        actions={diffButton}
+        actions={!file.is_binary && diffButton}
         file={file}
         contextMenu={this.openContextMenu}
         model={this.props.model}
@@ -387,12 +387,13 @@ export class FileList extends React.Component<IFileListProps, IFileListState> {
             title={this.props.trans.__('Stage all changes')}
             onClick={() => {
               // TODO open modal with confirmation to stage with merge conflicts
+              // TODO REMOVE ACTION 
             }}
           />
         }
         collapsible
         files={files}
-        heading={this.props.trans.__('Unmerged')}
+        heading={this.props.trans.__('Conflicted')}
         height={height}
         rowRenderer={this._renderUnmergedRow}
       />

src/model.ts

@@ -1166,6 +1166,23 @@ export class GitExtension implements IGitExtension {
     await this.commit(message);
   }
 
+  /**
+   * TODO: @navn
+   */
+  async getMergeDiff(filename: string): Promise<any> {
+    const path = await this._getPathRepository();
+    return await this._taskHandler.execute<any>(
+      'git:merge_diff:view', // TODO: what is this for?
+      async () => {
+        return await requestAPI<any>(
+          URLExt.join(path, 'merge_diff'),
+          'POST',
+          { filename }
+        );
+      }
+    );
+  }
+
   /**
    * Make request for a list of all git branches in the repository
    * Retrieve a list of repository branches.