From c14569c9f4d568e45229641e31e5d3790a813a9f Mon Sep 17 00:00:00 2001
From: Tony Sun <tony.sun427@gmail.com>
Date: Sat, 29 Aug 2020 09:43:09 -0700
Subject: [PATCH] fix bookmark passing with text indexes

Previously, we passed in the unpacked version of the bookmark with
the cursor inside the options field. This worked fine for _find because
we didn't need to return it to the user. But for _explain, we return
the value back as unpacked tuple instead of a string and jiffy:encode/1
complains. Now we correctly extract the bookmark out of options, unpack
it, and then pass it separately in it's own field. This way options
retains it's original string form for the user so that invalid_ejson
is not thrown.
---
 src/mango/src/mango_cursor_text.erl  | 17 +++++++++--------
 src/mango/test/08-text-limit-test.py | 10 ++++++++++
 2 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/src/mango/src/mango_cursor_text.erl b/src/mango/src/mango_cursor_text.erl
index 43ef84e4ce5..5989f342e02 100644
--- a/src/mango/src/mango_cursor_text.erl
+++ b/src/mango/src/mango_cursor_text.erl
@@ -43,7 +43,7 @@
 }).
 
 
-create(Db, Indexes, Selector, Opts0) ->
+create(Db, Indexes, Selector, Opts) ->
     Index = case Indexes of
         [Index0] ->
             Index0;
@@ -51,7 +51,7 @@ create(Db, Indexes, Selector, Opts0) ->
             ?MANGO_ERROR(multiple_text_indexes)
     end,
 
-    Opts = unpack_bookmark(couch_db:name(Db), Opts0),
+    Bookmark = unpack_bookmark(couch_db:name(Db), Opts),
 
     DreyfusLimit = get_dreyfus_limit(),
     Limit = erlang:min(DreyfusLimit, couch_util:get_value(limit, Opts, mango_opts:default_limit())),
@@ -66,7 +66,8 @@ create(Db, Indexes, Selector, Opts0) ->
         opts = Opts,
         limit = Limit,
         skip = Skip,
-        fields = Fields
+        fields = Fields,
+        bookmark = Bookmark
     }}.
 
 
@@ -90,7 +91,8 @@ execute(Cursor, UserFun, UserAcc) ->
         skip = Skip,
         selector = Selector,
         opts = Opts,
-        execution_stats = Stats
+        execution_stats = Stats,
+        bookmark = Bookmark
     } = Cursor,
     Query = mango_selector_text:convert(Selector),
     QueryArgs = #index_query_args{
@@ -104,7 +106,7 @@ execute(Cursor, UserFun, UserAcc) ->
         dbname = couch_db:name(Db),
         ddocid = ddocid(Idx),
         idx_name = mango_idx:name(Idx),
-        bookmark = get_bookmark(Opts),
+        bookmark = Bookmark,
         limit = Limit,
         skip = Skip,
         query_args = QueryArgs,
@@ -282,7 +284,7 @@ pack_bookmark(Bookmark) ->
 
 
 unpack_bookmark(DbName, Opts) ->
-    NewBM = case lists:keyfind(bookmark, 1, Opts) of
+    case lists:keyfind(bookmark, 1, Opts) of
         {_, nil} ->
             [];
         {_, Bin} ->
@@ -291,8 +293,7 @@ unpack_bookmark(DbName, Opts) ->
             catch _:_ ->
                 ?MANGO_ERROR({invalid_bookmark, Bin})
             end
-    end,
-    lists:keystore(bookmark, 1, Opts, {bookmark, NewBM}).
+    end.
 
 
 ddocid(Idx) ->
diff --git a/src/mango/test/08-text-limit-test.py b/src/mango/test/08-text-limit-test.py
index ae827813d7c..ef0509ff3a6 100644
--- a/src/mango/test/08-text-limit-test.py
+++ b/src/mango/test/08-text-limit-test.py
@@ -133,3 +133,13 @@ def run_bookmark_sort_check(self, size):
             assert json["bookmark"] != bm
             bm = json["bookmark"]
         assert len(seen_docs) == len(limit_docs.DOCS)
+
+    def run_explain_check(self, size):
+        q = {"age": {"$gt": 0}}
+        seen_docs = set()
+        bm = None
+        results1 = self.db.find(q, limit=size, bookmark=bm, return_raw=True)
+        assert results1["bookmark"] != bm
+        bm = results1["bookmark"]
+        results2 = self.db.find(q, limit=size, bookmark=bm, explain=True)
+        assert results2["bookmark"] == bm