unbundle: add a small comment to tag the bundle1 case as such This makes the code clearer to understand for someone new to it (or rusted)

unbundle: add a small comment to clarify the 'check_heads' call Bundle2 has its own mechanisms to check for heads (and other) changes, so push using bundle2 is relying on the "check:heads" bundle part of unbundle and the 'check_heads' call is not checking anything. We add a small comment to make this clearer.

pager: don't terminate with extreme prejudice on SIGPIPE (BC) The default SIGPIPE handler causes Mercurial to exit immediately, without running any Python cleanup code (except and finally blocks, atexit handlers etc). This creates problems if you want to do something at exit. If we need a different exit code for broken pipe from pager, then we should code that ourselves in Python; this appears to have been cargo-culted from the fork implementation of pager that's no longer used, where it was needed to stop Broken Pipe errors appearing on the user's terminal.

verify: replace _validpath() by matcher The verifier calls out to _validpath() to check if it should verify that path and the narrowhg extension overrides _validpath() to tell the verifier to skip that path. In treemanifest repos, the verifier calls the same method to check if it should visit a directory. However, the decision to visit a directory is different from the condition that it's a matching path, and narrowhg was working around it by returning True from its _validpath() override if *either* was true. Similar to how one can do "hg files -I foo/bar/ -X foo/" (making the include pointless), narrowhg can be configured to track the same paths. In that case match("foo/bar/baz") would be false, but match.visitdir("foo/bar/baz") turns out to be true, causing verify to fail. This may seem like a bug in visitdir(), but it's explicitly documented to be undefined for subdirectories of excluded directories. When using treemanifests, the walk would not descend into foo/, so verification would pass. However, when using flat manifests, there is no recursive directory walk and the file path "foo/bar/baz" would be passed to _validpath() without "foo/" (actually without the slash) being passed first. As explained above, _validpath() would return true for the file path and "hg verify" would fail. Replacing the _validpath() method by a matcher seems like the obvious fix. Narrowhg can then pass in its own matcher and not have to conflate the two matching functions (for dirs and files). I think it also makes the code clearer.

rebase: fix code comment to refer to right issue (4504, not 4505) The comment was introduced in 8a544fb645bb (rebase: ensure rebase revision remains visible (issue4504), 2015-01-27), which mentions the right issue in the description.

merge with stable

repair: use rawvfs when copying extra store files If we use the normal vfs, store encoding will be applied when we .join() the path to be copied. This results in attempting to copy a file that (likely) doesn't exist. Using the rawvfs operates on the raw file path, which is returned by vfs.readdir(). Users at Mozilla are encountering this, as I've instructed them to run `hg debugupgraderepo` to upgrade to generaldelta. While Mercurial shouldn't deposit any files under .hg/store that require encoding, it is possible for e.g. .DS_Store files to be created by the operating system.

tests: add test demonstrating buggy path handling `hg debugupgraderepo` is currently buggy with regards to path handling when copying files in .hg/store/. Specifically, it applies the store filename encoding to paths instead of operating on raw files. This commit adds a test demonstrating the buggy behavior.

repair: iterate store files deterministically An upcoming test will add a 2nd file. Since readdir() is non-deterministic, add a sorted() to make traversal deterministic.

Added signature for changeset ed5b25874d99

Added tag 4.1.2 for changeset ed5b25874d99

changegroup: store old heads as a set Previously, the "oldheads" variable was a list. On a repository at Mozilla with 46,492 heads, profiling revealed that list membership testing was dominating execution time of applying small changegroups. This patch converts the list of old heads to a set. This makes membership testing significantly faster. On the aforementioned repository with 46,492 heads: $ hg unbundle <file with 1 changeset> before: 18.535s wall after: 1.303s Consumers of this variable only check for truthiness (`if oldheads`), length (`len(oldheads)`), and (most importantly) item membership (`h not in oldheads` - which occurs twice). So, the change to a set should be safe and suitable for stable. The practical effect of this change is that changegroup application and related operations (like `hg push`) no longer exhibit an O(n^2) CPU explosion as the number of heads grows.

subrepo: move prompts out of the if (issue5505) Prompts weren't available in the else clause

exchange: use v2 bundles for modern compression engines (issue5506) Previously, `hg bundle zstd` on a non-generaldelta repo would attempt to use a v1 bundle. This would fail because zstd is not supported on v1 bundles. This patch changes the behavior to automatically use a v2 bundle when the user explicitly requests a bundlespec that is a compression engine not supported on v1. If the bundlespec is <engine>-v1, it is still explicitly rejected because that request cannot be fulfilled.

exchange: reject new compression engines for v1 bundles (issue5506) Version 1 bundles only support a fixed set of compression engines. Before this change, we would accept any compression engine for v1 bundles, even those that may not work on v1. This could lead to an error. We define a fixed set of compression engines known to work with v1 bundles and we add checking to ensure a newer engine (like zstd) won't work with v1 bundles. I also took the liberty of adding test coverage for unknown compression names because I noticed we didn't have coverage of it before.