Recover from ENOENT due to missing parent directory when trusting notebook (microsoft#12913)

Author: joyceerhl

src/client/datascience/interactive-ipynb/digestStorage.ts

@@ -26,10 +26,20 @@ export class DigestStorage implements IDigestStorage {
  public async saveDigest(uri: Uri, signature: string) {
  const fileLocation = await this.getFileLocation(uri);
  // Since the signature is a hex digest, the character 'z' is being used to delimit the start and end of a single digest
- await this.fs.appendFile(fileLocation, `z${signature}z\n`);
- if (!this.loggedFileLocations.has(fileLocation)) {
- traceInfo(`Wrote trust for ${uri.toString()} to ${fileLocation}`);
- this.loggedFileLocations.add(fileLocation);
+ try {
+ await this.saveDigestInner(uri, fileLocation, signature);
+ } catch (err) {
+ // The nbsignatures dir is only initialized on extension activation.
+ // If the user deletes it to reset trust, the next attempt to trust
+ // an untrusted notebook in the same session will fail because the parent
+ // directory does not exist.
+ if (isFileNotFoundError(err)) {
+ // Gracefully recover from such errors by reinitializing directory and retrying
+ await this.initDir();
+ await this.saveDigestInner(uri, fileLocation, signature);
+ } else {
+ traceError(err);
+ }
  }
  }
 
@@ -46,6 +56,14 @@ export class DigestStorage implements IDigestStorage {
  }
  }
 
+ private async saveDigestInner(uri: Uri, fileLocation: string, signature: string) {
+ await this.fs.appendFile(fileLocation, `z${signature}z\n`);
+ if (!this.loggedFileLocations.has(fileLocation)) {
+ traceInfo(`Wrote trust for ${uri.toString()} to ${fileLocation}`);
+ this.loggedFileLocations.add(fileLocation);
+ }
+ }
+
  private async getFileLocation(uri: Uri): Promise<string> {
  const normalizedName = os.platform() === 'win32' ? uri.fsPath.toLowerCase() : uri.fsPath;
  const hashedName = createHash('sha256').update(normalizedName).digest('hex');