feat(chat): add /listPatches command

Author: dsanders11

package.json

@@ -52,6 +52,10 @@
             "name": "findUpstreamFiles",
             "description": "Attempt to find upstream Chromium files that Electron files are derived from."
           },
+          {
+            "name": "listPatches",
+            "description": "List the patches that touch a given filename."
+          },
           {
             "name": "upgradesFindCL",
             "description": "Attempt to find the Chromium CL related to the current sync/build failure."

src/chat/commands/listPatches.ts

@@ -0,0 +1,109 @@
+import path from "node:path";
+
+import * as vscode from "vscode";
+
+import { type ElectronPatchesProvider } from "../../views/patches";
+
+async function fileExists(uri: vscode.Uri): Promise<boolean> {
+  try {
+    await vscode.workspace.fs.stat(uri);
+    return true;
+  } catch {
+    return false;
+  }
+}
+
+export async function listPatches(
+  chromiumRoot: vscode.Uri,
+  electronRoot: vscode.Uri,
+  patchesProvider: ElectronPatchesProvider,
+  request: vscode.ChatRequest,
+  stream: vscode.ChatResponseStream,
+  token: vscode.CancellationToken,
+) {
+  // Find the file the user is asking about
+  const filename = request.prompt.trim();
+  let patchedFile: vscode.Uri;
+
+  const absoluteFileUri = vscode.Uri.file(filename);
+  const chromiumRelativeFileUri = vscode.Uri.joinPath(chromiumRoot, filename);
+
+  if (await fileExists(absoluteFileUri)) {
+    patchedFile = absoluteFileUri;
+  } else if (await fileExists(chromiumRelativeFileUri)) {
+    patchedFile = chromiumRelativeFileUri;
+  } else {
+    stream.markdown("File not found");
+    return;
+  }
+
+  const patches = await vscode.workspace.findFiles(
+    new vscode.RelativePattern(
+      vscode.Uri.joinPath(electronRoot, "patches"),
+      "**/*.patch",
+    ),
+    null,
+    undefined,
+    token,
+  );
+
+  const matchingPatches = new Map<string, string[]>();
+
+  for (const patch of patches) {
+    const patchDirectory = vscode.Uri.file(path.dirname(patch.fsPath));
+    const checkoutDirectory =
+      await patchesProvider.getCheckoutDirectoryForPatchDirectory(
+        patchDirectory,
+      );
+    const relativeFilename = path.relative(
+      checkoutDirectory.fsPath,
+      patchedFile.fsPath,
+    );
+
+    if (relativeFilename.startsWith("..")) {
+      continue;
+    }
+
+    const contents = (await vscode.workspace.fs.readFile(patch)).toString();
+    if (
+      contents.includes(
+        `diff --git a/${relativeFilename} b/${relativeFilename}`,
+      )
+    ) {
+      const patchDirectoryName = path.basename(patchDirectory.fsPath);
+      if (!matchingPatches.has(patchDirectoryName)) {
+        matchingPatches.set(patchDirectoryName, []);
+      }
+      matchingPatches
+        .get(patchDirectoryName)!
+        .push(path.basename(patch.fsPath));
+    }
+  }
+
+  if (matchingPatches.size === 0) {
+    stream.markdown("No patches found");
+    return;
+  }
+
+  stream.markdown("Found the following patches for ");
+  stream.anchor(patchedFile);
+  stream.markdown(":\n");
+
+  // Output the final file tree
+  stream.filetree(
+    [
+      {
+        name: "patches",
+        children: Array.from(matchingPatches.entries()).map(
+          ([patchDirectory, patches]) => {
+            return {
+              name: patchDirectory,
+              children: patches.map((patch) => ({ name: patch })),
+            };
+          },
+        ),
+      },
+    ],
+    electronRoot,
+  );
+}

src/chat/participant.ts

@@ -1,15 +1,18 @@
 import * as vscode from "vscode";
 
 import { chatParticipantId } from "../constants";
+import { type ElectronPatchesProvider } from "../views/patches";
 
 import { findUpstreamFiles } from "./commands/findUpstreamFiles";
+import { listPatches } from "./commands/listPatches";
 import { upgradesFindCL } from "./commands/upgradesFindCL";
 import { searchCLs } from "./commands/searchCLs";
 import { getPrivateTools } from "./tools";
 
 export function registerChatParticipant(
   { extension, extensionUri }: vscode.ExtensionContext,
   electronRoot: vscode.Uri,
+  patchesProvider: ElectronPatchesProvider,
 ) {
   const chromiumRoot = vscode.Uri.joinPath(electronRoot, "..");
 
@@ -24,6 +27,15 @@ export function registerChatParticipant(
     if (request.command === "findUpstreamFiles") {
       await findUpstreamFiles(chromiumRoot, request, stream, token);
       return {};
+    } else if (request.command === "listPatches") {
+      await listPatches(
+        chromiumRoot,
+        electronRoot,
+        patchesProvider,
+        request,
+        stream,
+        token,
+      );
     } else if (
       request.command === "upgradesFindCL" ||
       request.command === "upgradesFindCLAdvanced"

src/extension.ts

@@ -499,7 +499,7 @@ export async function activate(context: vscode.ExtensionContext) {
           new DocsLinkCompletionProvider(linkableProvider),
           ...DocsLinkCompletionProvider.TRIGGER_CHARACTERS,
         ),
-        registerChatParticipant(context, electronRoot),
+        registerChatParticipant(context, electronRoot, patchesProvider),
       );
       registerElectronBuildToolsCommands(
         context,