store: use StoreEntry API instead of parsing filename when listing manifestlog This is more explicit and more robust.

store: use StoreEntry API instead of parsing filename when fixing issue6528 This is more explicit and more robust. We also introduce a small output change as it make things simpler and this is a affecting a debug-command.

store: use StoreEntry API instead of parsing filename in remotefilelog This is more explicit and more robust.

store: use StoreEntry API instead of parsing filename in narrow This is more explicit and more robust.

store: add a `target_id` attribute on RevlogStoreEntry This hold the "target" (file, directory, etc) of a revlog. Having this available will help a lot of code to avoid direct file path access.

store: actually tag tree manifest revlogs as manifest revlogs It turn out we have been mislabeling these for a long while. This is now fixed.

store: also gather files per revlog in `topfiles` This conclude out revlog gathering.

store: also group files by revlog in fncache version of datafiles One more step.

store: add logic to group revlog file together For now each file get its own entry, this will help stopping this, soon™. We use such gathering in the `basicstore` code.

store: change `_walk` return to `(filename, (type, size))` If we are to group file per revlog, having the filename as the "main key" will be useful. This change will make the following changes clearer.

store: lazily get file size on demand for the fncache case We don't have the information in the first place, so we can avoid querying the file system inconditionnaly for use case we don't needs it. This change requires the StoreFile class to be passed a vfs to retrieve the file_size if needed. In the non-fncache case, we already have the information from file system walking, so we keep it and use it.

store: only access is_volatile information through the file object This make sure other code only access this information through the proper API, and it prepare for store entries to be able to agregate multiple files.

store: only access file_size information through the file object This make sure other code only access this information through the proper API, and it prepare for store entries to be able to agregate multiple files.

store: have custom init for entries class This will get useful to add special processing later in this series.

store: use specialized class for store entries We introduce two different classes for revlog and other entries. For now, we still have multiple entry for the same revlog, but we will work toward grouping the different file in a single entry in this series. Having the distinction is a step toward this goal.

store: introduce a EntryFile object to actually access file info For now a StoreEntry match a single file, but the goal is to eventually combine multiple file in a higher level Entry, so we need to introduce this distinction and use it first.

store: use a StoreEntry object instead of tuple for store files We want to make the store return more semantic information instead of a stream of file path. To achieve this, we start with adding a simple object that hold the same information as the tuple it replace, and do a simple update to the user code to fetch and use the same information. From there, we will be able to iteratively upgrade the codebase toward better objects.

store: no longer explicitly mark the splitted index as ignored Since the fncache is going to automatically recognised it as non "normal" revlog file, we don't need to explicitly make it ignored.

store: cleanup what is recognized as a revlog file The temporary file from `censor` are not relevant to the store as they are just temporary. So let `fncache` and `datafiles` forget about them.

store: only inclure revlog related file in `datafiles` This is a "reading" equivalent of the previous patches (see that patch for details).

store: do not record file that are not part of a revlog in fncache The fncache exist to list file to copy/stream when cloning a repository, it should only contains file that are relevant for a revlog in such case. For example, temporary file are not relevant. So we now skip the addiction of non-relevant file to the fn-cache in the first place.

revlog-split: expand the some test to cover the success case too It seems useful to double check the case of a transaction successfully committed before trying the one with transaction abort.

transaction: use a ".bck" extension for all backup file There are too much code in Mercurial that assume file function from extension. Keeping the original extension when doing backup is just creating confusion (for exemple, backup of revlog's confused with new version revlogs). So we change the backup name from now on to be explicilty backup file and prevent this kind of problem. (note that repository using fncache is less affected (but still affected) by this kind of problem as the backup are not listed in the fncache).

repair-issue6528: remove a now useless continue The condition for that continue have been excplicly filtered out of the `files` list a handful of line earlier.