keepalive: discard legacy Python support for error handling We never changed the behavior defined by this attribute anyway, so just jettison all of this support.

mergemod: drop support for merge.update without a target This was to be deleted after 3.9.

dispatch: stop supporting non-use of @command We said we'd delete this after 3.8. It's time.

httppeer: document why super() isn't used Adding a follow-up to document lack of super() per Augie's request.

exchange: add `_getbookmarks()` function This function will be used to generate bookmarks bundle2 part. It is a separate function in order to make it easy to overwrite it in extensions. Passing `kwargs` to the function makes it easy to add new parameters in extensions.

bookmarks: use listbinbookmarks() in listbookmarks()

bookmarks: introduce listbinbookmarks() `bookmarks` bundle2 part will work with binary nodes. To avoid unnecessary conversions between binary and hex nodes let's add `listbinbookmarks()` that returns binary nodes. For now this function is a copy-paste of listbookmarks(). In the next patch this copy-paste will be removed.

ui: add configoverride context manager I feel like this idea might've been discussed before, so please feel free to point me to the right mailing list entry to read about why it should not be done. We have a common pattern of the following code: backup = ui.backupconfig(section, name) try: ui.setconfig(section, name, temporaryvalue, source) do_something() finally: ui.restoreconfig(backup) IMO, this looks better: with ui.configoverride({(section, name): temporaryvalue}, source): do_something() Especially this becomes more convenient when one has to backup multiple config values before doing something. In such case, adding a new value to backup requires codemod in three places.

archival: simplify code and drop message about Python 2.5

bugzilla: stop mentioning Pythons older than 2.6 We don't support those anyway.

tests: update sitecustomize to use uuid1() instead of randrange() The comments mention that uuid would be better, so let's go ahead and make good on an old idea.

win32mbcs: drop code that was catering to Python 2.3 and earlier

httppeer: drop an except block that says it happens only on Python 2.3

windows: do not replace sys.stdout by winstdout Now we use util.stdout everywhere.

py3: bulk replace sys.stdin/out/err by util's Almost all sys.stdin/out/err in hgext/ and mercurial/ are replaced by util's. There are a few exceptions: - lsprof.py and statprof.py are untouched since they are a kind of vendor code and they never import mercurial modules right now. - ui._readline() needs to replace sys.stdin and stdout to pass them to raw_input(). We'll need another workaround here.

py3: provide bytes stdin/out/err through util module Since standard streams are TextIO on Python 3, we can't use sys.stdin/out/err directly. Fortunately we can get the underlying BytesIO via .buffer as long as the streams aren't replaced by e.g. StringIO. stdin/out/err are provided through util so we can wrap them by platform API.

util: rewrite pycompat imports to make pyflakes always happy I'll add more imports which would confuse pyflakes.

windows: do not replace sys.__stdout__ Now we don't use sys.__stdout__ except for getting its fileno(), so we no longer have to wrap it by winstdout. This helps adding pycompat.stdin/out/err.

py3: update test-check-py3-compat.t output This part remains unchanged because it runs in Python 3 only.

py3: use pycompat.sysargv in dispatch.run() Another one to have a bytes result from sys.argv in Python 3. This one is also a part of running `hg version` on Python 3.

py3: use pycompat.sysargv in scmposix.systemrcpath() sys.argv returns unicodes on Python 3. We have pycompat.sysargv which returns bytes encoded using os.fsencode(). After this patch scmposix.systemrcpath() returns bytes in Python 3 world. This change is also a part of making `hg version` run in Python 3.

wireproto: perform chunking and compression at protocol layer (API) Currently, the "streamres" response type is populated with a generator of chunks with compression possibly already applied. This puts the onus on commands to perform chunking and compression. Architecturally, I think this is the wrong place to perform this work. I think commands should say "here is the data" and the protocol layer should take care of encoding the final bytes to put on the wire. Additionally, upcoming commits will improve wire protocol support for compression. Having a central place for performing compression in the protocol transport layer will be easier than having to deal with compression at the commands layer. This commit refactors the "streamres" response type to accept either a generator or an object with "read." Additionally, the type now accepts a flag indicating whether the response is a "version 1 compressible" response. This basically identifies all commands currently performing compression. I could have used a special type for this, but a flag works just as well. The argument name foreshadows the introduction of wire protocol changes, hence the "v1." The code for chunking and compressing has been moved to the output generation function for each protocol transport. Some code has been inlined, resulting in the deletion of now unused methods.

httppeer: use compression engine API for decompressing responses In preparation for supporting multiple compression formats on the wire protocol, we need all users of the wire protocol to use compression engine APIs. This commit ports the HTTP wire protocol client to use the compression engine API. The code for handling the HTTPException is a bit hacky. Essentially, HTTPException could be thrown by any read() from the socket. However, as part of porting the API, we no longer have a generator wrapping the socket and we don't have a single place where we can trap the exception. We solve this by introducing a proxy class that intercepts read() and converts the exception appropriately. In the future, we could introduce a new compression engine API that supports emitting a generator of decompressed chunks. This would eliminate the need for the proxy class. As I said when I introduced the decompressorreader() API, I'm not fond of it and would support transitioning to something better. This can be done as a follow-up, preferably once all the code is using the compression engine API and we have a better idea of the API needs of all the consumers.

httppeer: do decompression inside _callstream The current HTTP transport protocol only compresses certain command responses and requires calls to that command to call "_callcompressable," which zlib decompresses the response transparently. Upcoming changes will enable *any* response to be compressed with varying compression formats. In order to handle this better, this commit moves the decompression bits to the main function performing the HTTP request. We introduce an underscore-prefixed argument to denote this behavior so it doesn't conflict with a named argument to a command.

keepalive: reorder header precedence There are 3 sources of headers used by this function: * The default headers defined by the URL opener * Headers that are copied on redirects * Headers that aren't copied on redirects Previously, we applied the default headers from the URL opener last. This feels wrong to me as those headers are the most low level and something built on top of the URL opener may wish to override them. So, this commit changes the order to apply them with the least precedence. While I was here, I removed a Python version test that is no longer necessary.

debuginstall: print compression engine support Since compression engines may be provided by extensions and since not all registered compression engines may be available to use, it seems useful to provide a mechanism to see the state of known compression engines. This commit teaches `hg debuginstall` to print info on known and available compression engines.

bdiff: don't check border condition in loop This is pretty much a copy of d500ddae7494, just to a different loop. The condition `p == plast` (`plast == a + len - 1`) was only true on the final iteration of the loop. So it was wasteful to check for it on every iteration. We decrease the iteration count by 1 and add an explicit check for `p == plast` after the loop. Again, we see modest wins. From the mozilla-unified repository: $ perfbdiff -m 3041e4d59df2 ! wall 0.035502 comb 0.040000 user 0.040000 sys 0.000000 (best of 100) ! wall 0.030480 comb 0.030000 user 0.030000 sys 0.000000 (best of 100) $ perfbdiff 0e9928989e9c --alldata --count 100 ! wall 4.097394 comb 4.100000 user 4.100000 sys 0.000000 (best of 3) ! wall 3.597798 comb 3.600000 user 3.600000 sys 0.000000 (best of 3) The 2nd example throws a total of ~3.3GB of data at bdiff. This change increases the throughput from ~811 MB/s to ~924 MB/s.

conflicts: make spacing consistent in conflict markers The way default marker template was defined before this patch, the spacing before dash in conflict markes was dependent on whether changeset is a tip one or not. This is a relevant part of template: '{ifeq(tags, "tip", "", "{tags} "}' If revision is a tip revision with no other tags, this would resolve to an empty string, but for revisions which are not tip and don't have any other tags, this would resolve to a single space string. In the end this causes weirdnesses like the ones you can see in the affected tests. This is a not a big deal, but double spacing may be visually less pleasant. Please note that test changes where commit hashes change are the result of marking files as resolved without removing markers.