**! ! Warning**: Do not merge before testing every API call and database
read involving JSON !
**Gson** is obsolete and has been superseded by **Moshi**. But more
importantly, parsing Kotlin objects using Gson is _dangerous_ because
Gson uses Java serialization and is **not Kotlin-aware**. This has two
main consequences:
- Fields of non-null types may end up null at runtime. Parsing will
succeed, but the code may crash later with a `NullPointerException` when
trying to access a field member;
- Default values of constructor parameters are always ignored. When
absent, reference types will be null, booleans will be false and
integers will be zero.
On the other hand, Kotlin-aware parsers like **Moshi** or **Kotlin
Serialization** will validate at parsing time that all received fields
comply with the Kotlin contract and avoid errors at runtime, making apps
more stable and schema mismatches easier to detect (as long as logs are
accessible):
- Receiving a null value for a non-null type will generate a parsing
error;
- Optional types are declared explicitly by adding a default value. **A
missing value with no default value declaration will generate a parsing
error.**
Migrating the entity declarations from Gson to Moshi will make the code
more robust but is not an easy task because of the semantic differences.
With Gson, both nullable and optional fields are represented with a null
value. After converting to Moshi, some nullable entities can become
non-null with a default value (if they are optional and not nullable),
others can stay nullable with no default value (if they are mandatory
and nullable), and others can become **nullable with a default value of
null** (if they are optional _or_ nullable _or_ both). That third option
is the safest bet when it's not clear if a field is optional or not,
except for lists which can usually be declared as non-null with a
default value of an empty list (I have yet to see a nullable array type
in the Mastodon API).
Fields that are currently declared as non-null present another
challenge. In theory, they should remain as-is and everything will work
fine. In practice, **because Gson is not aware of nullable types at
all**, it's possible that some non-null fields currently hold a null
value in some cases but the app does not report any error because the
field is not accessed by Kotlin code in that scenario. After migrating
to Moshi however, parsing such a field will now fail early if a null
value or no value is received.
These fields will have to be identified by heavily testing the app and
looking for parsing errors (`JsonDataException`) and/or by going through
the Mastodon documentation. A default value needs to be added for
missing optional fields, and their type could optionally be changed to
nullable, depending on the case.
Gson is also currently used to serialize and deserialize objects to and
from the local database, which is also challenging because backwards
compatibility needs to be preserved. Fortunately, by default Gson omits
writing null fields, so a field of type `List<T>?` could be replaced
with a field of type `List<T>` with a default value of `emptyList()` and
reading back the old data should still work. However, nullable lists
that are written directly (not as a field of another object) will still
be serialized to JSON as `"null"` so the deserializing code must still
be handling null properly.
Finally, changing the database schema is out of scope for this pull
request, so database entities that also happen to be serialized with
Gson will keep their original types even if they could be made non-null
as an improvement.
In the end this is all for the best, because the app will be more
reliable and errors will be easier to detect by showing up earlier with
a clear error message. Not to mention the performance benefits of using
Moshi compared to Gson.
- Replace Gson reflection with Moshi Kotlin codegen to generate all
parsers at compile time.
- Replace custom `Rfc3339DateJsonAdapter` with the one provided by
moshi-adapters.
- Replace custom `JsonDeserializer` classes for Enum types with
`EnumJsonAdapter.create(T).withUnknownFallback()` from moshi-adapters to
support fallback values.
- Replace `GuardedBooleanAdapter` with the more generic `GuardedAdapter`
which works with any type. Any nullable field may now be annotated with
`@Guarded`.
- Remove Proguard rules related to Json entities. Each Json entity needs
to be annotated with `@JsonClass` with no exception, and adding this
annotation will ensure that R8/Proguard will handle the entities
properly.
- Replace some nullable Boolean fields with non-null Boolean fields with
a default value where possible.
- Replace some nullable list fields with non-null list fields with a
default value of `emptyList()` where possible.
- Update `TimelineDao` to perform all Json conversions internally using
`Converters` so no Gson or Moshi instance has to be passed to its
methods.
- ~~Create a custom `DraftAttachmentJsonAdapter` to serialize and
deserialize `DraftAttachment` which is a special entity that supports
more than one json name per field. A custom adapter is necessary because
there is not direct equivalent of `@SerializedName(alternate = [...])`
in Moshi.~~ Remove alternate names for some `DraftAttachment` fields
which were used as a workaround to deserialize local data in 2-years old
builds of Tusky.
- Update tests to make them work with Moshi.
- Simplify a few `equals()` implementations.
- Change a few functions to `val`s
- Turn `NetworkModule` into an `object` (since it contains no abstract
methods).
Please test the app thoroughly before merging. There may be some fields
currently declared as mandatory that are actually optional.
There are some new rules, I think they mostly make sense, except for the
max line length which I had to disable because we are over it in a lot
of places.
---------
Co-authored-by: Goooler <wangzongler@gmail.com>
The idea here is: Everytime we get hold of a new version of a post, we
update everything about that post everywhere.
This makes the distincion between different event types unnecessary, as
everythng is just a `StatusChangedEvent`.
The main benefit is that posts should be up-to-date more often, which is
important considering there is now editing and #3413
- Extend what was `NotificationWorkerFactory` to `WorkerFactory`. This
can construct arbitrary Workers as long as they provide their own
Factory for construction.
The per-Worker factory contains any injected components just for that
worker type, keeping `WorkerFactory` clean.
- Move `NotificationWorkerFactory` to the new model.
- Implement `PruneCacheWorker`, and remove the code from
`CachedTimelineViewModel`.
- Create the periodic worker in `TuskyApplication`, ensuring that the
database is only pruned when the device is idle.
- Add a field to AccountEntity to hold the reading position
- Provide a method to save in the viewmodel to save the position
- Save the position when TimelineFragment pauses
Does not restore the position yet.
* Replace "warn"-filtered posts in timelines and thread view with placeholders
* Adapt hashtag muting interface
* Rework filter UI
* Add icon for account preferences
* Clean up UI
* WIP: Use chips instead of a list. Adjust padding
* Scroll the filter edit activity
Nested scrolling views (e.g., an activity that scrolls with an embedded list
that also scrolls) can be difficult UI.
Since the list of contexts is fixed, replace it with a fixed collection of
switches, so there's no need to scroll the list.
Since the list of actions is only two (warn, hide), and are mutually
exclusive, replace the spinner with two radio buttons.
Use the accent colour and title styles on the different heading titles in
the layout, to match the presentation in Preferences.
Add an explicit "Cancel" button.
The layout is a straightforward LinearLayout, so use that instead of
ConstraintLayout, and remove some unncessary IDs.
Update EditFilterActivity to handle the new layout.
* Cleanup
* Add more information to the filter list view
* First pass on code review comments
* Add view model to filters activity
* Add view model to edit filters activity
* Only use the status wrapper for filtered statuses
* Relint
---------
Co-authored-by: Nik Clayton <nik@ngo.org.uk>
* Change "Load more" to load oldest statuses first in home timeline
Previous behaviour loaded missing statuses by using "since_id" and "max_id".
This loads the most recent N statuses, looking backwards from "max_id".
Change to load the oldest statuses first, assuming the user is scrolling
up through the timeline and will want to load statuses in reverse
chronological order.
* Scroll to the bottom of new entries added by "Load more"
- Remember the position of the "Load more" placeholder
- Check the position of inserted entries
- If they match, scroll to the bottom
* Change "Load more" to load oldest statuses first in home timeline
Previous behaviour loaded missing statuses by using "since_id" and "max_id".
This loads the most recent N statuses, looking backwards from "max_id".
Change to load the oldest statuses first, assuming the user is scrolling
up through the timeline and will want to load statuses in reverse
chronological order.
* Scroll to the bottom of new entries added by "Load more"
- Remember the position of the "Load more" placeholder
- Check the position of inserted entries
- If they match, scroll to the bottom
* Ensure the user can't have two simultaneous "Load more" coroutines
Having two simultanous coroutines would break the calculation used to figure
out which item in the list to scroll to after a "Load more" in the timeline.
Do this by:
- Creating a TimelineUiState and associated flow that tracks the "Load more"
state
- Updating this in the (Cached|Network)TimelineViewModel
- Listening for changes to it in TimelineFragment, and notifying the adapter
- The adapter will disable any placeholder views while "Load more" is active
* Revert changes that loaded the oldest statuses instead of the newest
* Be more robust about locating the status to scroll to
Weirdness with the PagingData library meant that positionStart could still be
wrong after "Load more" was clicked.
Instead, remember the position of the "Load more" item and the ID of the
status immediately after it.
When new items are added, search for the remembered status at the position of
the "Load more" item. This is quick, testing at most LOAD_AT_ONCE items in
the adapter.
If the remembered status is not visible on screen then scroll to it.
* Lint
* Add a preference to specify the reading order
Default behaviour (oldest first) is for "load more" to load statuses and
stay at the oldest of the new statuses.
Alternative behaviour (if the user is reading from top to bottom) is to
stay at the newest of the new statuses.
* Move ReadingOrder enum construction logic in to the enum
* Jump to top if swipe/refresh while preferring newest-first order
* Show a circular progress spinner during "Load more" operations
Remove a dedicated view, and use an icon on the button instead.
Adjust the placeholder attributes and styles accordingly.
* Remove the "loadMoreActive" property
Complicates the code and doesn't really achieve the desired effect. If the
user wants to tap multiple "Load more" buttons they can.
* Update comments in TimelineFragment
* Respect the user's reading order preference if it changes
* Add developer tools
This is for functionality that makes it easier for developers to interact
with the app, or get it in to a known-state.
These features are for use by users, so are only visible in debug builds.
* Adjust how content is loaded based on preferred reading order
- Add the readingOrder to TimelineViewModel so derived classes can use it.
- Update the homeTimeline API to support the `minId` parameter and update
calls in NetworkTimelineViewModel
In CachedTimelineViewModel:
- Set the bounds of the load to be the status IDs on either side of the
placeholder ID (update TimelineDao with a new query for this)
- Load statuses using either minId or sinceId depending on the reading order
- Is there was no overlap then insert the new placeholder at the start/end
of the list depending on reading order
* Lint
* Rename unused dialog parameter to _
* Update API arguments in tests
* Simplify ReadingOrder preference handling
* Fix bug with Placeholder and the "expanded" property
If a status is a Placeholder the "expanded" propery is used to indicate
whether or not it is loading.
replaceStatusRange() set this property based on the old value, and the user's
alwaysOpenSpoiler preference setting.
This shouldn't have been used if the status is a Placeholder, as it can lead
to incorrect loading states.
Fix this.
While I'm here, introduce an explicit computed property for whether a
TimelineStatusEntity is a placeholder, and use that for code clarity.
* Set the "Load more" button background to transparent
* Fix typo.
* Inline spec, update comment
* Revert 1480c6aa3a
Turns out the behaviour is not desired.
* Remove unnecessary Log call
* Extract function
* Change default to newest first
Loading of statuses and loading of filters is an "intended" race:
we want to display statuses first, especially if they are cached.
Unfortunately we do not cache filters themselves so when we load cached
statuses we do not apply filters.
One part of the solution is to re-filter the statuses once we fetch the
filters. This commit implements it. Caching of filters is not included
yet.
* update gradle, kotlin and other dependencies
* fix new warnings
* remove unused import
* update Proguard rules
* add explicit dependency on Gson to get the newest version
* remove debug flag from proguard rules again
* fix typo
* first setup
* network timeline paging / improvements
* rename classes / move to correct package
* remove unused class TimelineAdapter
* some code cleanup
* remove TimelineRepository, put mapper functions in TimelineTypeMappers.kt
* add db migration
* cleanup unused code
* bugfix
* make default timeline settings work again
* fix pinning statuses from timeline
* fix network timeline
* respect account settings in NetworkTimelineRemoteMediator
* respect account settings in NetworkTimelineRemoteMediator
* update license headers
* show error view when an error occurs
* cleanup some todos
* fix db migration
* fix changing mediaPreviewEnabled setting
* fix "load more" button appearing on top of timeline
* fix filtering and other bugs
* cleanup cache after 14 days
* fix TimelineDAOTest
* fix code formatting
* add NetworkTimeline unit tests
* add CachedTimeline unit tests
* fix code formatting
* move TimelineDaoTest to unit tests
* implement removeAllByInstance for CachedTimelineViewModel
* fix code formatting
* fix bug in TimelineDao.deleteAllFromInstance
* improve loading more statuses in NetworkTimelineViewModel
* improve loading more statuses in NetworkTimelineViewModel
* fix bug where empty state was shown too soon
* reload top of cached timeline on app start
* improve CachedTimelineRemoteMediator and Tests
* improve cached timeline tests
* fix some more todos
* implement TimelineFragment.removeItem
* fix ListStatusAccessibilityDelegate
* fix crash in NetworkTimelineViewModel.loadMore
* fix default state of collapsible statuses
* fix default state of collapsible statuses -tests
* fix showing/hiding media in the timeline
* get rid of some not-null assertion operators in TimelineTypeMappers
* fix tests
* error handling in CachedTimelineViewModel.loadMore
* keep local status state when refreshing cached statuses
* keep local status state when refreshing network timeline statuses
* show placeholder loading state in cached timeline
* better comments, some code cleanup
* add TimelineViewModelTest, improve code, fix bug
* fix ktlint
* fix voting in boosted polls
* code improvement
Christophe Beyls
Willow
Konrad Pozniak
Nik Clayton
Levi Bard