1058108 - [DataStore] 'get' call fails to trigger any promise callbacks when fetching all entries from an empty store.

Status: VERIFIED FIXED

Description

[Aus Lacroix [:aus]]

[Blocking Requested - why for this release]:

When attempting to fetch all records from an empty datastore, the underlying promise that is returned never gets called and DataStoreImpl throws an exception. We should, at the very least, call onerror and ideally, call onsuccess with an empty array of results.

Comment 1

[Andrea Marchesini [:baku]]

> When attempting to fetch all records from an empty datastore, the underlying
> promise that is returned never gets called and DataStoreImpl throws an
> exception. We should, at the very least, call onerror and ideally, call
> onsuccess with an empty array of results.

How do you fetch all the records? Using 'sync'?

Comment 2

[Aus Lacroix [:aus]]

Here's where we fetch all the records via 'get': https://github.com/mozilla-b2g/gaia/blob/master/shared/js/download/download_store.js#L317

This fails everytime when the datastore is empty. As soon as there is one entry everything works as expected.

Comment 3

[Andrea Marchesini [:baku]]

Created attachment 8478436 [details] [diff] [review]
length.patch

With this patch the promise is resolved with an empty array.

Comment 4

[Boris Zbarsky [:bz] (no decent commit message means r-)]

That doesn't look right to me.  You're resolving with a chrome array, no?

Comment 5

[Andrea Marchesini [:baku]]

Created attachment 8478457 [details] [diff] [review]
length.patch

I also changed the other array.
This is cleaner, but also with the previous patch it worked fine.

Comment 6

[Aus Lacroix [:aus]]

I believe I've seen this occur on b2g-2.0 as well, I've flagged QA to check against 2.0 and 1.4.

STRs:

1. Flash Flame (319M) with latest b2g-2.0 + gaia
2. In the browser, go to http://owd.tid.es/dm/
3. Download 97MB.rar
4. Tap on the download started notification, it will take you to the downloads list in settings.

Expected: Currently active download status.

Actual: Empty list.

Once there is one successful download, everything works as expected.

Comment 7

[Jason Smith [:jsmith]]

Josh - Can you have someone look into this qawanted request?

Comment 8

[Joshua Mitchell (Inactive)]

This issue DOES reproduce in Flame 2.0 and Flame 1.4

Actual Results - Blank Download Screen until 1 file has been completely downloaded; resulting in an inability to stop the current download (when it is the first download)

Device: Flame 2.0
Build ID: 20140823033754
Gaia: 4c8b5ced1966079086d86dec3098ecf340881306
Gecko: b0545e46d08b
Version: 32.0 (2.0)
Firmware Version: v123
User Agent: Mozilla/5.0 (Mobile; rv:32.0) Gecko/32.0 Firefox/32.0

Device: Flame 1.4
Build ID: 20140825062151
Gaia: cf9d74da6653efeb43d9653e81c61aa00e693a67
Gecko: cdcb73d0febc
Version: 30.0 (1.4)
Firmware Version: v123
User Agent: Mozilla/5.0 (Mobile; rv:30.0) Gecko/30.0 Firefox/30.0

Comment 9

[Aus Lacroix [:aus]]

Based on comment #8 and as the "downloads" guy for b2g I would suggest blocking 2.0 and 1.4 (or at least landing on 1.4 for flatfish et al).

Comment 10

[Andrea Marchesini [:baku]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/75805f95cfbe

Comment 11

[Aus Lacroix [:aus]]

[Blocking Requested - why for this release]:

Without this fix, the first time the user downloads a file, they will be unable to stop the active download because the downloads list will always be empty. This could cause them to incur data charges that they would normally be able to prevent.

Comment 12

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/75805f95cfbe

Comment 13

[Bruce Huang [:bhuang] (inactive)]

Taking this on 1.4 due to hidden data costs to user.

Comment 14

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/releases/mozilla-b2g30_v1_4/rev/94a33c8895cc

This will need explicit b2g32 approval if it's needed for v2.0 as well.

Comment 15

[Andrea Marchesini [:baku]]

Comment on attachment 8478457 [details] [diff] [review]
length.patch

NOTE: This flag is now for security issues only. Please see https://wiki.mozilla.org/Release_Management/B2G_Landing to better understand the B2G approval process and landings.

[Approval Request Comment]
Bug caused by (feature/regressing bug #): bug 916089
User impact if declined: some apps can be broken.
Testing completed: m-c. Fully covered.
Risk to taking this patch (and alternatives if risky): None
String or UUID changes made by this patch: None

Comment 16

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/releases/mozilla-b2g32_v2_0/rev/543cf0f2306d

Comment 17

[Kai-Zhen Li [:seinlin][:kli]]

http://hg.mozilla.org/releases/mozilla-b2g32_v2_0m/rev/759969e0b807

Comment 18

[Yeojin Chung [:YeojinC]]

This issue is verified fixed on Flame 2.1(KK), 2.0(KK), and 1.4(JB), following STRs on Comment 6.

Result: The Download list displays the current downloading status properly.
  
Flame 2.1

Device: Flame 2.1 (319mb)(Kitkat Base)(Full Flash)
BuildID: 20141027001201
Gaia: c97463d61f45513a2123b19610386ddbfc916819
Gecko: 4f8c0c021128
Gonk: 6e51d9216901d39d192d9e6dd86a5e15b0641a89
Version: 34.0 (2.1)
Firmware: V188
User Agent: Mozilla/5.0 (Mobile; rv:34.0) Gecko/34.0 Firefox/34.0

Flame 2.0

Device: Flame 2.0 (319mb)(Kitkat Base)(Full Flash)
BuildID: 20141027000202 
Gaia: 2183b4f3ec0eb47ab1f133c31732ec53b08ad253
Gecko: 43bee45176c4
Gonk: 6e51d9216901d39d192d9e6dd86a5e15b0641a89
Version: 32.0 (2.0)
Firmware: V188
User Agent: Mozilla/5.0 (Mobile; rv:32.0) Gecko/32.0 Firefox/32.0

Flame 1.4

Device: Flame 1.4 (319mb)(Jelly Bean Base)
BuildID: 20141027000203
Gaia: bb76c81f83e1e4acc2d2972a451db2bce78c8f34
Gecko: 1bde54b2e7b0
Version: 30.0 (1.4)
Firmware: V123
User Agent: Mozilla/5.0 (Mobile; rv:30.0) Gecko/30.0 Firefox/30.0
=====================================================

Leaving verifyme keyword for 2.0M. We do not have any device to check on 2.0M.

Comment 19

[Coler]

This issue has been verified successfully on Woodduck 2.0 with STRs in Comment 6 .
Reproducing rate: 0/5
See attachment: Verify_Woodduck_Downloadlist.mp4

build version:
Gaia-Rev        87b23fa81c3b59f2ba24b84f7d686f4160d4e7cb
Gecko-Rev       d049d4ef127844121c9cf14d2e8ca91fd9045fcb
Build-ID        20141125050313
Version         32.0

Comment 20

[Coler]

Created attachment 8528116 [details]
Verify_Downloadlist.mp4