packaging: replace dockerlib.sh with a Python script I want to do some more advanced things with Docker in upcoming commits. Trying to do that with shell scripts will be a bit too painful for my liking. Implementing things in Python will be vastly simpler in the long run. This commit essentially ports dockerlib.sh to a Python script. dockerdeb and dockerrpm have been ported to use the new hg-docker script. hg-docker requires Python 3. I've only tested on Python 3.5. Unlike the local packaging scripts which may need to run on old distros, the Docker packaging scripts don't have these constraints. So I think it is acceptable to require Python 3.5. As part of the transition, the Docker image tags changed slightly. I don't think that's a big deal: the Docker image names are effectively arbitrary and are a means to an end to achieve running commands in Docker containers. The code for resolving the Dockerfile content allows substituting values passed as arguments. This will be used in a subsequent commit. Differential Revision: https://phab.mercurial-scm.org/D3759

packaging: consistently create build user in Dockerfiles Previously, dockerlib.sh appended some commands to create a "build" user in each Docker image. The resulting Docker images could be inconsistent depending on the execution environment and base image. With this change, we explicitly create our custom user and group as the first action in each Dockerfile. The user always has user:group 1000:1000 and all built images are consistent. We also create a home directory for the user under /build. This directory is currently ignored. As part of this, we stop setting the DBUILDUSER variable in dockerlib.sh and instead set it in the respective scripts that call it. This is in preparation for further refactoring of dockerlib.sh. Differential Revision: https://phab.mercurial-scm.org/D3758

scmutil: move construction of instability count message to separate fn When the commad we are running, introduces new instabilities, we show a message like `5 new orphan changesets`, `2 new content-divergent changesets`, `1 new phase-divergent changesets` etc which is very nice. Now taking a step ahead, we want users to show how to fix them too. Something like: `5 new orphan changesets (run 'hg evolve' to resolve/stabilize them)` `2 new content-divergent changesets (run 'hg evolve --content-divergent' to resolve them)` and maybe telling user a way to understand more about those new instabilities like `hg evolve --list` or `hg log -r 'orphan()'` something like that. The idea came from issue5855 which I want to fix because fixing that will result in a nice UI. Taking the construction logic out will allow extensions like evolve (maybe rebase too) to wrap that and add information about how to resolve and how to understand the instability more. Differential Revision: https://phab.mercurial-scm.org/D3734

procutil: use unbuffered stdout on Windows Windows doesn't support line buffering, treating it as fully buffered. This causes output of slow commands to stutter. We use unbuffered instead.

procutil: use unbuffered stdout on Windows Windows doesn't support line buffering, treating it as fully buffered. This causes output of slow commands to stutter. We use unbuffered instead.

graft: introduce --abort flag to abort interrupted graft This patch introduces a new --abort flag to `hg graft` command which aborts an interrupted graft and rollbacks to the state before graft. The behavior when some of grafted changeset get's published while interrupted graft or we have new descendants on grafted changesets is same as that of rebase which is warn the user, don't strip and abort the abort the graft. Tests are added for the new flag. .. feature:: `hg graft` now has a `--abort` flag which aborts the interrupted graft and rollbacks to state before the graft. Differential Revision: https://phab.mercurial-scm.org/D3754

graft: move `if continue` to elif and add new line This will make upcoming patch where we introduce a new elif for the abort case more readable. Also added a new line before the if-else starts. Differential Revision: https://phab.mercurial-scm.org/D3752

graft: start storing new nodes formed in graftstate This patch starts storing the new nodes formed during the ongoing graft operation in the graftstate. We need the list of new nodes formed while implmenting `graft --abort` which will strip out the new nodes. Differential Revision: https://phab.mercurial-scm.org/D3751

show: use filter() function to strip "tip" tag Before, an empty tag "" was inserted in place of "tip", resulting in double spaces.

templater: extend filter() to accept template expression for emptiness test This utilizes the pass-by-name nature of template arguments.