At a high level, this is what I've done and why:
- I'm moving the protobuf generation for the `protocol`, `discovery` and
`db` packages to the modern alternatives, and using `buf` to generate
because it's nice and simple.
- After trying various approaches on how to integrate the new types with
the existing code, I opted for splitting off our own data model types
from the on-the-wire generated types. This means we can have a
`FileInfo` type with nicer ergonomics and lots of methods, while the
protobuf generated type stays clean and close to the wire protocol. It
does mean copying between the two when required, which certainly adds a
small amount of inefficiency. If we want to walk this back in the future
and use the raw generated type throughout, that's possible, this however
makes the refactor smaller (!) as it doesn't change everything about the
type for everyone at the same time.
- I have simply removed in cold blood a significant number of old
database migrations. These depended on previous generations of generated
messages of various kinds and were annoying to support in the new
fashion. The oldest supported database version now is the one from
Syncthing 1.9.0 from Sep 7, 2020.
- I changed config structs to be regular manually defined structs.
For the sake of discussion, some things I tried that turned out not to
work...
### Embedding / wrapping
Embedding the protobuf generated structs in our existing types as a data
container and keeping our methods and stuff:
```
package protocol
type FileInfo struct {
*generated.FileInfo
}
```
This generates a lot of problems because the internal shape of the
generated struct is quite different (different names, different types,
more pointers), because initializing it doesn't work like you'd expect
(i.e., you end up with an embedded nil pointer and a panic), and because
the types of child types don't get wrapped. That is, even if we also
have a similar wrapper around a `Vector`, that's not the type you get
when accessing `someFileInfo.Version`, you get the `*generated.Vector`
that doesn't have methods, etc.
### Aliasing
```
package protocol
type FileInfo = generated.FileInfo
```
Doesn't help because you can't attach methods to it, plus all the above.
### Generating the types into the target package like we do now and
attaching methods
This fails because of the different shape of the generated type (as in
the embedding case above) plus the generated struct already has a bunch
of methods that we can't necessarily override properly (like `String()`
and a bunch of getters).
### Methods to functions
I considered just moving all the methods we attach to functions in a
specific package, so that for example
```
package protocol
func (f FileInfo) Equal(other FileInfo) bool
```
would become
```
package fileinfos
func Equal(a, b *generated.FileInfo) bool
```
and this would mostly work, but becomes quite verbose and cumbersome,
and somewhat limits discoverability (you can't see what methods are
available on the type in auto completions, etc). In the end I did this
in some cases, like in the database layer where a lot of things like
`func (fv *FileVersion) IsEmpty() bool` becomes `func fvIsEmpty(fv
*generated.FileVersion)` because they were anyway just internal methods.
Fixes#8247
This truncates times meant for API consumption to second precision,
where fractions won't typically matter or add any value. Exception to
this is timestamps on logs and events, and of course I'm not touching
things like file metadata.
I'm not 100% certain this is an exhaustive change, but it's the things I
found by grepping and following the breadcrumbs from lib/api...
I also considered general-but-ugly solutions, like having the API
serializer itself do reflection magic or even regexps on returned
objects, but decided against it because aurgh...
* lib/db: Add ExpirePendingFolders().
Use-case is to drop any no-longer-pending folders for a specific
device when parsing its ClusterConfig message where previously offered
folders are not mentioned any more.
The timestamp in ObservedFolder is stored with only second precision,
so round to seconds here as well. This allows calling the function
within the same second of adding or updating entries.
* lib/model: Weed out pending folders when receiving ClusterConfig.
Filter the entries by timestamp, which must be newer than or equal to
the reception time of the ClusterConfig. For just mentioned ones,
this assumption will hold as AddOrUpdatePendingFolder() updates the
timestamp.
* lib/model, gui: Notify when one or more pending folders expired.
Introduce new event type FolderOfferCancelled and use it to trigger a
complete refreshCluster() cycle. Listing individual entries would be
much more code and probably just as much work to answer the API
request.
* lib/model: Add comment and rename ExpirePendingFolders().
* lib/events: Rename FolderOfferCancelled to ClusterPendingChanged.
* lib/model: Reuse ClusterPendingChanged event for cleanPending()
Changing the config does not necessarily mean that the
/resut/cluster/pending endpoints need to be refreshed, but only if
something was actually removed. Detect this and indicate it through
the ClusterPendingChanged event, which is already hooked up to requery
respective endpoints within the GUI.
No more need for a separate refreshCluster() in reaction to
ConfigSaved event or calling refreshConfig().
* lib/model: Gofmt.
* lib/db: Warn instead of info log for failed removal.
* gui: Fix pending notifications not loading on GUI start.
* lib/db: Use short device ID in log message.
* lib/db: Return list of expired folder IDs after deleting them.
* lib/model: Refactor Pending...Changed events.
* lib/model: Adjust format of removed pending folders enumeration.
Use an array of objects with device / folder ID properties, matching
the other places where it's used.
* lib/db: Drop invalid entries in RemovePendingFoldersBeforeTime().
* lib/model: Gofmt.
My local gofmt did not complain here, strangely...
* gui: Handle PendingDevicesChanged event.
Even though it currently only holds one device at a time, wrap the
contents in an array under the "added" property name.
* lib/model: Fix null values in PendingFoldersChanged removed member.
* gui: Handle PendingFoldersChanged event.
* lib/model: Simplify construction of expiredPendingList.
* lib/model: Reduce code duplication in cleanPending().
Use goto and a label for the common parts of calling the DB removal
function and building the event data part.
* lib/events, gui: Mark ...Rejected events deprecated.
Extend comments explaining the conditions when the replacement event
types are emitted.
* lib/model: Wrap removed devices in array of objects as well.
* lib/db: Use iter.Value() instead of needless db.Get(iter.Key())
* lib/db: Add comment explaining RemovePendingFoldersBeforeTime().
* lib/model: Rename fields folderID and deviceID in event data.
* lib/db: Only list actually expired IDs as removed.
Skip entries where Delete() failed as well as invalid entries that got
removed automatically.
* lib/model: Gofmt
