Mercurial: Changelog

narrow: pass node into revlog.revision() This is one of the few (possibly only) places where we pass an int in for filelogs. Other revlogs (notably changelog) are very heavy on int usage. But filelogs are surprisingly node centric. I'd like to formalize the interface around the use of nodes (at least for filelogs). So let's switch to a node. We can't inline revlog.node() because of a check-code rule. I think that rule is suspect. But it may be for performance reasons with changelog code. I'd rather not touch it at this time. Differential Revision: https://phab.mercurial-scm.org/D3043

changegroup: remove "revlog" from error message The previous message leaked an implementation detail. Differential Revision: https://phab.mercurial-scm.org/D3041

tests: conditionalize tests based on presence of revlogs for files ~85 tests don't like our non-revlog file store for various reasons. This commit introduces hghave functionality for declaring and querying repository features. By default, we assume repositories have revlog-based file storage. But if the HGREPOFEATURES environment variable is set, we can override the default set of repository features. If you run the test harness with our simplestorerepo extension and an environment variable set to the proper value, you can override the hghave defaults to agree with simplestorerepo's version of reality. Various tests have been modified so behavior dependent on revlog-based file storage is marked as such. This fixes a handful of test failures with our custom file storage extension. But dozens remain. The point of this commit is to demonstrate how tests will need to be modified to account for custom storage implementations. TBH, I'm not convinced hghave is the proper layer for repository feature detection. I /think/ we'll eventually want something in run-tests.py itself. But that would require inventing a new primitive in the test harness. This is all very alpha at the moment. So I think hghave is an acceptable place to hang this feature detection. I think the right time to be thinking about integrating this into run-tests.py is *after* we have a stable alternate storage implementation in core. For now, let's try to make progress towards the idea of an alternate storage backend. Differential Revision: https://phab.mercurial-scm.org/D3030

tests: add test extension implementing custom filelog storage In order to better support partial clones, we'll need alternate repository storage mechanisms that aren't based on revlogs. Today, the interface for repository storage isn't very well defined. And there are various layering violations and assumptions made throughout the code that storage is backed by revlogs. In order to support alternate storage mechanisms, we'll need to formally declare and adhere to interfaces for storage. This will be a long, arduous process. This commit creates an extension that implements non-revlog storage for files. It defines a custom type that quacks like the existing revlog/filelog API but isn't backed by a revlog. The backing storage is - for simplicity reasons - a CBOR index and per-node files representing fulltext data. The localrepository class is modified so file(f) returns instances of this class instead of filelog instances. The purpose of this extension is to tease out what the actual filelog interface is - based on running the test harness - so we can formalize that interface and then implement a *real* alternate storage backend. Using `run-tests.py --extra-config-opt` to run the test harness with this extension enabled yields 83 failures out of 634 ran tests. The most common test failures are due to: * Issues with `hg verify` * LFS and largefiles (probably flags processing related) * Narrow. * Any test touching or inspecting individual filelog paths. * help and error output that is confused by the presence of an extension. * `hg debug*` commands doing low-level, revlog-y things. An 88% pass rate is pretty good for an initial implementation if you ask me! There is a bit of duplicate code in the new extension. That's by design: a point of this code is to tease out dependencies on revlog. That being said, there is opportunity to consolidate code by moving things out of the revlog API. For example, DAG traversal operations don't necessarily need to be implemented at the storage level. (Although for performance reasons they probably do.) Once we have a more well-defined interface, we could probably define the default implementations in terms of the base interface, pull those in via class inheritance, and have implementations override with faster versions if they so choose. (Or something like that.) But for now, the duplicate code should be acceptable. Differential Revision: https://phab.mercurial-scm.org/D3029

tests: use `hg unbundle` instead of `hg pull` in some tests `hg pull <bundle>` uses the special "bundlerepo" repository. The bundlerepo code makes many assumptions about the storage of repositories. It will be difficult to teach bundlerepo to use non-revlog storage before a better storage interface is established. Many test failures using our "simple store" are related to bundlerepo: the simple store just isn't compatible with bundlerepo because of storage assumptions in bundlerepo. In order to mitigate the impact of bundlerepo on our code base, this commit changes various tests to use `hg unbundle` instead of `hg pull`. This bypasses the bundlerepo code. Tests exercising exchange functionality have not been altered, as they should be using `hg pull` and going through the bundlerepo code paths. Differential Revision: https://phab.mercurial-scm.org/D3059