localrepo: don't reference transaction from hook closure (issue5043) Before, the hook() closure (which is called as part of locking hooks) would maintain a reference to a transaction instance (which should be finalized by the time lock hooks are called). Because we accumulate hook() instances when there are multiple transactions per lock, this would result in holding references to the transaction instances which would lead to higher memory utilization. Creating a reference to the hook arguments dict minimizes the number of objects that are kept alive until the lock release hook runs, minimizing memory "leaks."

context: don't use util.cachefunc due to cycle creation (issue5043) util.cachefunc stores all arguments as the cache key. For filectxfn functions, the arguments include the memctx instance. This creates a cycle where memctx._filectxfn references self. This causes a memory leak. We break the cycle by implementing our own memoizing function that only uses the path as the cache key. Since each memctx has its own cache instance, there is no concern about invalid cache hits.

largefiles: actions will now always have a file - drop check

largefiles: make prompt order deterministic 42ae1b1f048f introduced iteration of a set. Make it stable.

largefiles: fix commit of missing largefiles 832c98d79587 improved merging of standin files referencing missing largefiles. It did however not test or fix commits of such merges; it would abort. To fix that, change copytostore to skip and warn about missing largefiles with a message similar the one for failing get from remote filestores. (It would perhaps in both cases be better to emit a more helpful warning like "warning: standin file for large1 references 58e24f733a which can't be found in the local store".) To test this, make sure commit doesn't find the "missing" largefile in the global usercache. For further testing, verify that update and status works as expected after this. This will also effectively backout 63116d47cc3f.

diff: don't crash when merged-in addition is copied Similar to what was explained in the previous commit, the diff code expected copy source to be in "ctx1", which is not always the case during a merge. This has been broken since before hg 2.0. Also similar to the previous commit, we fix the problem by fixing up the copy dict.

diff: don't crash when merged-in addition was removed (issue4786) During a merge, if the user removes a file that came from parent 2 and did not exist in parent 1, the file's status will be "removed". This surprises the diff code, which crashes because it expects removed files exist in parent 1. This has been broken since 377124ba6b10 (trydiff: use 'not in addedset' for symmetry with 'not in removedset', 2014-12-23). Fix by fixing up the list of removed file, similar to how we currently fix up the list of modified and added files during a merge.

diff: move status fixup earlier, out of _filepairs() This prepares for future patches, and it also lets us remove the ugly "ctx1" argument to _filepairs() (ugly because of its assymmetry -- there's no "ctx2" argument).

graft: warn when -r is combined with revisions as positional arguments The behaviour in this case is undefined. Instead of silently doing something "random" and surprising, at least issue a warning. (This should perhaps be considered a "deprecation" and turned into an error in a future release.)

graft: clarify in help that `-r` is not just optional Positional parameters are also treated as revisions, but the order of revisions matters and it will often be wrong if the user understands it as `-r` taking multiple revisions as `-r REV1 REV2`. (Alternatively, `-r` could be turned into a no-op flag as the documentation suggests. That would however be less "semantic markup" and I agree with the implementation in 55e7f352b1d3 but not the documentation.)

streamclone: use backgroundfilecloser (issue4889) Closing files that have been appended to is slow on Windows/NTFS. CloseHandle() calls on this platform often take 1-10ms - and that's on my i7-6700K Skylake processor with a modern and fast SSD. Contrast with other I/O operations, such as writing data, which take <100us. This means that creating/appending thousands of files can add significant overhead. For example, cloning mozilla-central creates ~232,000 revlog files. Assuming 1ms per CloseHandle(), that yields 232s (3:52) of wall time waiting for file closes! The impact of this overhead can be measured most directly when applying stream clone bundles. Applying these files is effectively uncompressing a tar archive (read: it's very fast). Using a RAM disk (read: no I/O wait), the difference in wall time for a `hg debugapplystreamclonebundle` for a ~1731 MB mozilla-central bundle between Windows and Linux from the same machine is drastic: Linux: ~12.8s (128MB/s) Windows: ~352.0s (4.7MB/s) Windows is ~27.5x slower. Yikes! After this patch: Linux: ~12.8s (128MB/s) Windows: ~102.1s (16.1MB/s) Windows is now ~3.4x faster. Unfortunately, it is still ~8x slower than Linux. Profiling reveals a few hot code paths that could likely be improved. But those are for other patches. This patch introduces test-clone-uncompressed.t because existing tests of `clone --uncompressed` are scattered about and adding a variation for background thread closing to e.g. test-http.t doesn't feel correct.

streamclone: indent code This will make the subsequent patch easier to read.

scmutil: support background file closing Closing files that have been appended to is relatively slow on Windows/NTFS. This makes several Mercurial operations slower on Windows. The workaround to this issue is conceptually simple: use multiple threads for I/O. Unfortunately, Python doesn't scale well to multiple threads because of the GIL. And, refactoring our code to use threads everywhere would be a huge undertaking. So, we decide to tackle this problem by starting small: establishing a thread pool for closing files. This patch establishes a mechanism for closing file handles on separate threads. The coordinator object is basically a queue of file handles to operate on and a thread pool consuming from the queue. When files are opened through the VFS layer, the caller can specify that delay closing is allowed. A proxy class for file handles has been added. We must use a proxy because it isn't possible to modify __class__ on built-in types. This adds some overhead. But as future patches will show, this overhead is cancelled out by the benefit of closing file handles on background threads.

templatekw: add {namespaces} keyword This provides a general-purpose interface to all custom namespaces. The {namespaces} keyword honors the definition order of namespaces as they are kept by sortdict.

templatekw: move shownames() helper to be sorted alphabetically I'll add shownamespaces(), which is similar to this function. I want to put them nearby.

templater: make get(dict, key) return a single value This is necessary to obtain a _hybrid object from a dict. If get() yields a value, it would be stringified. I see no benefit to make get() lazy, so this patch just changes "yield" to "return".

templater: make _hybrid not callable to avoid conflicting semantics In templater, a callable symbol exists for lazy evaluation, which should have f(**mapping) signature. On the other hand, _hybrid.__call__(), which was introduced by 0b241d7a8c62, generates mapping for each element. This patch renames _hybrid.__call__() to _hybrid.itermaps() so that a _hybrid object can be a value of a mapping dict. {namespaces % "{namespace}: {names % "{name }"}\n"} ~~~~~ a _hybrid object

backout: commit changeset by default (BC) Add --no-commit flag to prevent it. This should make the hg user experience a little better. Some discussion can be found here: http://markmail.org/message/7jm7ro2ias6hxywy

help: move Windows 9x information to appropriate place

shelve: move commitfunc closer to use site Supporting shelving of unknown files needs this code motion. No functional changes.

commands: document clone bundles hooks and rollback behavior The added content is inside a verbose container. I figure it makes sense to explicitly document behavior, including with the caveat it may change later. People can't say they weren't warned!

clonebundles: improve BUNDLESPEC documentation Before the existence of `hg debugbundle --spec`, the process for defining the BUNDLESPEC value in manifests was not very clear and not trivial to automate, especially in the case of stream clone bundles. This patch adds documentation to note the existence of `hg debugbundle --spec`. We drop the reference to stream clone requirements handling because it is now redundant with `hg debugbundle --spec`. While we are here, we further reinforce the importance of defining BUNDLESPEC.

commands: teach debugbundle to print bundle specification This seems like the most logical place to put this functionality. Test coverage over existing known bundle specs has been added.

commands: use context manager for opened bundle file