localrepo: move requirements reasonability testing to own function Just because we know how to handle each listed requirement doesn't mean that set of requirements is reasonable. This commit introduces an extension-wrappable function to validate that a set of requirements makes sense. We could combine this with ensurerequirementsrecognized(). But I think having a line between basic membership testing and compatibility checking is more powerful as it will help differentiate between missing support and buggy behavior. Differential Revision: https://phab.mercurial-scm.org/D4571

statichttprepo: use new functions for requirements validation The new code in localrepo for requirements gathering and validation is more robust than scmutil.readrequires(). Let's port statichttprepo to it. Since scmutil.readrequires() is no longer used, it has been removed. It is possible extensions were monkeypatching this to supplement the set of supported requirements. But the proper way to do that is to register a featuresetupfuncs. I'm comfortable forcing the API break because featuresetupfuncs is more robust and has been supported for a while. .. api:: ``scmutil.readrequires()`` has been removed. Use ``localrepo.featuresetupfuncs`` to register new repository requirements. Use ``localrepo.ensurerequirementsrecognized()`` to validate them. Differential Revision: https://phab.mercurial-scm.org/D4570

localrepo: validate supported requirements in makelocalrepository() This should be a glorified code move. I did take the opportunity to refactor things. We now have a separate function for gathering requirements and one for validating them. I also mode cosmetic changes to the code, such as not using abbreviations and using a set instead of list to model missing requirements. Differential Revision: https://phab.mercurial-scm.org/D4569

localrepo: read requirements file in makelocalrepository() Previously, scmutil.readrequires() loaded the requirements file and validated its content against what was supported. Requirements translate to repository features and are critical to our plans to dynamically create local repository types. So, we must load them in makelocalrepository() before a repository instance is constructed. This commit moves the reading of the .hg/requires file to makelocalrepository(). Because scmutil.readrequires() was performing I/O and validation, we inlined the validation into localrepository.__init__ and removed scmutil.readrequires(). I plan to remove scmutil.readrequires() in a future commit (we can't do it now because statichttprepo uses it). Differential Revision: https://phab.mercurial-scm.org/D4568

localrepo: check for .hg/ directory in makelocalrepository() As part of this, we move the check to before .hg/hgrc is loaded, as it makes sense to check for the directory before attempting to open a file in it. Differential Revision: https://phab.mercurial-scm.org/D4567

localrepo: load extensions in makelocalrepository() Behavior does change subtly. First, we now load the hgrc before optionally setting up the vfs ward. That's fine: the vfs ward is for debugging and we know we won't hit it when reading .hg/hgrc. If the loaded extension were performing repo/vfs I/O, then we'd be worried. But extensions don't have access to the repo object that loaded them when they are loaded. Unless they are doing stack walking as part of module loading (which would be crazy), they shouldn't have access to the repo that incurred their load. Second, we now load extensions outside of the try..except IOError block. Previously, if loading an extension raised IOError, it would be silently ignored. I'm pretty sure the IOError is there for missing .hgrc files and should never have been ignored for issues loading extensions. I don't think this matters in reality because extension loading traps I/O errors. Differential Revision: https://phab.mercurial-scm.org/D4566

localrepo: copy ui in makelocalrepository() We will want to load the .hg/hgrc file from makelocalrepository() so we can consult its options as part of deriving the repository type. This means we need to create our ui instance copy in that function. Differential Revision: https://phab.mercurial-scm.org/D4565

localrepo: move some vfs initialization out of __init__ In order to make repository types more dynamic, we'll need to move the logic for determining repository behavior out of localrepository.__init__ so we can influence behavior before the type is instantiated. This commit starts that process by moving working directory and .hg/ vfs initialization to our new standalone function for instantiating local repositories. Aside from API changes, behavior should be fully backwards compatible. .. api:: localrepository.__init__ now does less work and accepts new args Use ``hg.repository()``, ``localrepo.instance()``, or ``localrepo.makelocalrepository()`` to obtain a new local repository instance instead of calling the ``localrepository`` constructor directly. Differential Revision: https://phab.mercurial-scm.org/D4564

localrepo: create new function for instantiating a local repo object Today, there is a single local repository class - localrepository. Its __init__ is responsible for loading the .hg/requires file and taking different actions depending on what is present. In addition, extensions may define a "reposetup" function that monkeypatches constructed repository instances, often by implementing a derived type and changing the __class__ of the repo instance. Work around alternate storage backends and partial clone has made it clear to me that shoehorning all this logic into __init__ and operating on an existing instance is too convoluted. For example, localrepository assumes revlog storage and swapping in non-revlog storage requires overriding e.g. file() to return something that isn't a revlog. I've authored various patches that either: a) teach various methods (like file()) about different states and taking the appropriate code path at run-time b) create methods/attributes/callables used for instantiating things and populating these in __init__ "a" incurs run-time performance penalties and makes code more complicated since various functions have a bunch of "if storage is X" branches. "b" makes localrepository quickly explode in complexity. My plan for tackling this problem is to make the local repository type more dynamic. Instead of a static localrepository class/type that supports all of the local repository configurations (revlogs vs other, revlogs with ellipsis, revlog v1 versus revlog v2, etc), we'll dynamically construct a type providing the implementations that are needed for the repository on disk, derived from the .hg/requires file and configuration options. The constructed repository type will be specialized and methods won't need to be taught about different implementations nor overloaded. We may also leverage this functionality for building types that don't implement all attributes. For example, the "intents" feature allows commands to declare that they are read only. By dynamically constructing a repository type, we could return a repository instance with no attributes related to mutating the repository. This could include things like a "changelog" property implementation that doesn't check whether it needs to invalidate the hidden revisions set on every access. This commit establishes a function for building a local repository instance. Future commits will start moving functionality from localrepository.__init__ to this function. Then we'll start dynamically changing the returned type depending on options that are present. This change may seem radical. But it should be fully compatible with the reposetup() model - at least for now. Differential Revision: https://phab.mercurial-scm.org/D4563

transaction: make entries a private attribute (API) This attribute is tracking changes to append-only files. It is an implementation detail and should not be exposed as part of the public interface. But code in repair was accessing it, so it seemingly does belong as part of the public API. But that code in repair is making assumptions about how storage works and is grossly wrong when alternate storage backends are in play. We'll need some kind of "strip" API at the storage layer that knows how to handle things in a storage-agnostic manner. I don't think accessing a private attribute on the transaction is any worse than what this code is already doing. So I'm fine with violating the abstraction for transactions. And with this change, all per-instance attributes on transaction have been made private except for "changes" and "hookargs." Both are used by multiple consumers and look like they need to be part of the public interface. .. api:: Various attributes of ``transaction.transaction`` are now ``_`` prefixed to indicate they shouldn't be used by external consumers. Differential Revision: https://phab.mercurial-scm.org/D4634

transaction: make names a private attribute This is used to report the transaction name in __repr__. It is very obviously an implementation detail and doesn't need to be exposed as part of the public interface. So mark it as private. Differential Revision: https://phab.mercurial-scm.org/D4633

transaction: make map a private attribute This is used to track which files are modified. It is an implementation detail of current transactions and doesn't need to be exposed to the public interface. So mark it as private. Differential Revision: https://phab.mercurial-scm.org/D4632

transaction: make report a private attribute This is a callable used for logging. It isn't used outside the transaction code. It doesn't need to be part of the public interface. Let's mark it as private. Differential Revision: https://phab.mercurial-scm.org/D4631

transaction: make opener a private attribute The VFS instance is an implementation detail of the transaction and doesn't belong as part of the public interface. So mark it as private. Differential Revision: https://phab.mercurial-scm.org/D4630

transaction: make after a private attribute This is another callable that is passed in at __init__ time. It doesn't need to be part of the public interface. Differential Revision: https://phab.mercurial-scm.org/D4629

transaction: make checkambigfiles a private attribute This holds instance state that is passed in at __init__ time. It doesn't need to be exposed as part of the public interface. Differential Revision: https://phab.mercurial-scm.org/D4628

transaction: make validator a private attribute This is similar to releasefn. It holds state that doesn't need to be exposed as part of the public interface. Differential Revision: https://phab.mercurial-scm.org/D4627

transaction: make releasefn a private attribute This is a handle on a callable that is called when the journal is closed. The value is specified at __init__ time. It doesn't need to be exposed on the public interface. So mark it as private. Differential Revision: https://phab.mercurial-scm.org/D4626

transaction: make file a private attribute This holds a file handle for the journal file. This file handle should not be touched outside the journal class and doesn't belong on the public interface. Differential Revision: https://phab.mercurial-scm.org/D4625

transaction: make journal a private attribute This attribute tracks the name of the journal file. It is an implementation detail of the current transaction and therefore shouldn't be exposed as part of the interface. Let's mark it as private. Differential Revision: https://phab.mercurial-scm.org/D4624

transaction: make undoname a private attribute This attribute tracks the file pattern to use for undo files. It is an implementation detail of the current transaction semantics and doesn't need to be part of the future transaction interface. So mark it as private. Differential Revision: https://phab.mercurial-scm.org/D4623

transaction: make count and usages private attributes I want to formalize the interface for transactions. As part of doing that, let's take the opportunity to make some attributes non-public. "count" and "usages" track how many times the transaction has been opened/nested/closed/released. This is internal state and doesn't need to be part of the public API. Differential Revision: https://phab.mercurial-scm.org/D4622

narrow: don't send the changelog information when widening without ellipses When we widen anon-ellipses narrow copy, the server sends the changelog information of all the changesets. The code was copied from ellipses case and in ellipses cases, it's required to send the new changelog data. But in non-ellipses cases, we don't need to send the changelog data as we will have all the changesets locally. Before this patch, there was a overhead of ~8-10 mins on each widening call because of all the changelog information being pulled and being applied. After this patch, we no more pull the changelog information. So this patch can save ~5 mins on Mozilla repo on each widening and more on repos which have more changesets. When we apply an empty changelog from changegroup, there is a devel-warn. This patch kind of hacks to silence that devel-warn. Differential Revision: https://phab.mercurial-scm.org/D4639

changegroup: add functionality to skip adding changelog data to changegroup In narrow extension, when we have a non-ellipses narrow working copy and we extend it, we pull all the changelog data again and the client tries to reapply all that changelog data. While downloading millions of changeset data is still not very expensive but applying them on the client side is very expensive and takes ~10 minutes. These 10 minutes are added to every `hg tracked --addinclude <>` call and extending a narrow copy becomes very slow. This patch adds a new changelog argument to cgpacker.generate() fn. If the changelog argument is set to False, we won't yield the changelog data. We still have to iterate over the deltas returned by _generatechangelog() because that's a generator and builds the data for clstate variable which is required for calculating manifests and filelogs. Differential Revision: https://phab.mercurial-scm.org/D4638