[ALOY-1686] Alloy: App crashes due to context used when accessing Ti.Database API

GitHub Issue	n/a
Type	Bug
Priority	None
Status	Closed
Resolution	Fixed
Resolution Date	2019-05-16T13:38:31.000+0000
Affected Version/s	Alloy 1.13.9
Fix Version/s	CLI Release 7.0.12, Alloy 1.13.10
Components	Models
Labels	n/a
Reporter	Hans Knöchel
Assignee	Christopher Williams
Created	2019-05-02T09:27:34.000+0000
Updated	2019-05-17T14:05:35.000+0000

Description

The current master is broken due to changes in the Obj-C JSCore interface (TIMOB-26038):

[ERROR] Script Error {
[ERROR]     column = 38;
[ERROR]     line = 214;
[ERROR]     message = "self type check failed for Objective-C instance method";
[ERROR]     sourceURL = "file:///Users/hans/Library/Developer/CoreSimulator/Devices/884D0F2B-46F2-41D5-AA78-C26BC42BF348/data/Containers/Bundle/Application/B1994734-79D4-40DD-9003-C940456A903D/Lambus.app/alloy/sync/sql.js";
[ERROR]     stack = "    at [native code]\n    at Sync(/alloy/sync/sql.js:214:38)\n    at sync(/alloy.js:92:22)\n    at fetch(/alloy/backbone.js:344:47)\n    at (/app.js:45:24)\n    at global code(/app.js:225:70)\n    at require@[native code]\n    at (/ti.main.js:8997:10)\n    at doLoad(/ti.main.js:8955:15)\n    at loadBootstrapScripts(/ti.main.js:8967:11)\n    at loadAsync(/ti.main.js:8972:23)\n    at global code(/ti.main.js:8994:10)";
[ERROR]     toJSON = "<KrollCallback: 0x600000bfba40>";
[ERROR] }

Specifically, changes in Ti.Database seem to have caused this issues. It was triggered by Alloy models which use Backbone in the background which uses Ti.Database in the background. To reproduce, simply create a new Alloy app and create a model as documented in the docs. For the core-team: This is also reproducible in the app you guys have access to. *EDIT*: After investigating this, it seems like [this selector](https://github.com/appcelerator/titanium_mobile/pull/10381/files#diff-d0e600e43c92d0fe06ffee452771f44cR125) is causing the issues as it's referenced in the sql.js to get the field from the result-set at the specified index.

Comments

Hans Knöchel 2019-05-02

cc [~cwilliams] [~jvennemann]
Hans Knöchel 2019-05-06

Any update here? We're trying to stay on latest master to report back all issues, but this one is currently breaking us.
Hans Knöchel 2019-05-13

Another attempt to ping this…Does this really need to slip into a GA again to get people's attention on this? Every app that uses Ti.Database will be broken and I have no idea how the unit tests could have allowed this to be merged.
Christopher Williams 2019-05-15

So at first glance this looks to me like a latent bug in Alloy that happened not to trigger before (oddly). It plays around with the result set's field method a little: var getField = OS_ANDROID || OS_WINDOWS ? rs.field.bind(rs) : rs.field; Notice that on Windows or Android it uses bind to explicitly tie this to the ResultSet instance. On iOS it does not. As a result, this is implicitly the global object: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_objects/Function/bind Changing that line to always use bind on all platforms fixes the issue. Or simply calling rs.field(i); which is much more common usage - I'm not sure why this redirection was used in the first place. Note that we ran into this exact same bug before on Windows (using JSCore) in TIMOB-20577.
Christopher Williams 2019-05-15

https://github.com/appcelerator/alloy/pull/930
Hans Knöchel 2019-05-15

[~cwilliams] Issue fixed, thank you so much!!
Ewan Harris 2019-05-16

1_13_X backport: https://github.com/appcelerator/alloy/pull/931
Samir Mohammed 2019-05-17
Samir Mohammed 2019-05-17

Closing ticket also verified using CLI 7.1.0-master.16 with the above steps.

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