revset: allow to parse single integer as a range Even though this wouldn't be any useful in followlines(), it helps to unify range processing.

revset: extract a helper to parse integer range It's getting common. As a first step, this patch adds getintrange() and makes followlines() use it. I wanted to unify the error messages to make the function interface simple, but I failed to phrase it briefly.

commit: if interactive, look elsewhere for whitespace settings (BC) Previously, when doing `commit -i`, we respected `diff.ignorews` and other whitespace-related settings, which is probably unexpected. The primary reason for this is to support hgext.record's commandline options, it's probably accidental that the `[diff]` settings were also considered. See comments on issue6042 and D5490. This can cause problems (issue5839, issue6042). It is assumed by the author that the `[diff]` section is primarily for *viewing* diffs, and that it is unlikely what people intend when attempting to commit or revert. With this change, if a user wants the behavior, they can clone their `[diff]` settings to `commands.commit.interactive.<setting>`. This is thus a mild BC change, but one I suspect is not going to be relied on by anyone. Note: while doing a partial commit/revert, we do not know what command the user is actually running. This means that the split extension, which ends up calling into this code, will respect the `commands.commit.interactive.<setting>` settings, and not a hypothetical `commands.split.interactive.<setting>`. This *also* means that setting `commands.commit.interactive.ignoreblanklines`, for example, will still cause issue5839. Considering the highly unlikely chance that a user actually sets `commands.commit.interactive.<setting>`, the author deems this risk acceptable. Differential Revision: https://phab.mercurial-scm.org/D5834

diff: when looking for diff configs, support a configurable prefix In a future commit, I want to make it possible to have the diff options pulled from (as an example) `commands.commit.interactive.ignorews`; previously we only supported this for customizable sections (so this would have needed a `commit-interactive` section and been named `commit-interactive.ignorews`, which felt a bit weird. Differential Revision: https://phab.mercurial-scm.org/D5833

config: extract diff-related coreconfigitem()s to a helper method We already have 'annotate' and 'diff' that use the same set of options, and I want to add more in a followup commit, so I'm attempting to reduce maintenance burden and duplication by making it possible to register all of them at once. Differential Revision: https://phab.mercurial-scm.org/D5832

commit: ignore diff whitespace settings when doing `commit -i` (issue5839) Previously, we respected options like `diff.ignoreblanklines` and `diff.ignorews`. This can cause problems when the user is attempting to actually commit the blank line change. Specifically, the split extension can get into an infinite loop because it detects that the working copy is not clean, but when we get the diff we don't see the changes, so it just skips popping up the chunk selection flow, saying there's no changes to record. These options are primarily meant for viewing diffs; it is highly unlikely that someone is actually intending to add extraneous whitespace and have it ignored if they attempt to interactively commit (but *not* ignored if they non-interactively commit). Differential Revision: https://phab.mercurial-scm.org/D5744

tests: add syntax warnings on Python 3.8 in python-zstandard These are warnings from upstream test code. Let's just acknowledge them for now. These should go away in a future python-zstandard release :) Differential Revision: https://phab.mercurial-scm.org/D5846

check-py3-compat: manually format and print warnings The warnings mechanism may print to stderr on Python 3. Independent buffering of stdout and stderr can lead to warnings output not being printed properly. This commit traps warnings when executing individual files and prints warnings to stdout so output is deterministic. Differential Revision: https://phab.mercurial-scm.org/D5845

check-py3-compat: provide filename to ast.parse() This ensures any warning/error messages print a valid filename instead of potentially '<unknown>'. Differential Revision: https://phab.mercurial-scm.org/D5844

doc: escape backslash This avoids a SyntaxWarning on Python 3.8 due to invalid \ escape. Differential Revision: https://phab.mercurial-scm.org/D5843