From 37308832b1bcf0b8cfc8f68965aea7df4914d896 Mon Sep 17 00:00:00 2001
From: Nick Craig-Wood <nick@craig-wood.com>
Date: Wed, 17 Jun 2020 11:58:01 +0100
Subject: [PATCH] drive: fix --drive-impersonate with cached root_folder_id

Before this fix rclone v1.51 and 1.52 would incorrectly use the cached
root_folder_id when the --drive-impersonate flag was in use. This
meant that rclone could be looking up the wrong directory ID with
unpredictable results - usually all files apparently being missing.

This fix makes rclone look up the root_folder_id always when using
--drive-impersonate. It does this by clearing the root_folder_id and
making a NOTICE message that it is ignoring the cached value.

It also stops rclone caching the root_folder_id when using
--drive-impersonate.

See: https://forum.rclone.org/t/rclone-gdrive-no-longer-returning-anything/17215
---
 backend/drive/drive.go | 27 ++++++++++++++++++++++-----
 1 file changed, 22 insertions(+), 5 deletions(-)

diff --git a/backend/drive/drive.go b/backend/drive/drive.go
index 7c0a9c457..58909299f 100755
--- a/backend/drive/drive.go
+++ b/backend/drive/drive.go
@@ -349,9 +349,12 @@ date is used.`,
 			Help:     "Size of listing chunk 100-1000. 0 to disable.",
 			Advanced: true,
 		}, {
-			Name:     "impersonate",
-			Default:  "",
-			Help:     "Impersonate this user when using a service account.",
+			Name:    "impersonate",
+			Default: "",
+			Help: `Impersonate this user when using a service account.
+
+Note that if this is used then "root_folder_id" will be ignored.
+`,
 			Advanced: true,
 		}, {
 			Name:    "alternate_export",
@@ -1118,9 +1121,20 @@ func NewFs(name, path string, m configmap.Mapper) (fs.Fs, error) {
 		}
 	}
 
+	// If impersonating warn about root_folder_id if set and unset it
+	//
+	// This is because rclone v1.51 and v1.52 cached root_folder_id when
+	// using impersonate which they shouldn't have done. It is possible
+	// someone is using impersonate and root_folder_id in which case this
+	// breaks their workflow. There isn't an easy way around that.
+	if opt.RootFolderID != "" && opt.Impersonate != "" {
+		fs.Logf(f, "Ignoring cached root_folder_id when using --drive-impersonate")
+		opt.RootFolderID = ""
+	}
+
 	// set root folder for a team drive or query the user root folder
 	if opt.RootFolderID != "" {
-		// override root folder if set or cached in the config
+		// override root folder if set or cached in the config and not impersonating
 		f.rootFolderID = opt.RootFolderID
 	} else if f.isTeamDrive {
 		f.rootFolderID = f.opt.TeamDriveID
@@ -1137,7 +1151,10 @@ func NewFs(name, path string, m configmap.Mapper) (fs.Fs, error) {
 			}
 		}
 		f.rootFolderID = rootID
-		m.Set("root_folder_id", rootID)
+		// Don't cache the root folder ID if impersonating
+		if opt.Impersonate == "" {
+			m.Set("root_folder_id", rootID)
+		}
 	}
 
 	f.dirCache = dircache.New(root, f.rootFolderID, f)