* Add `builtin_immutable_heads()` in the `revsets.toml`.
* Redefine `immutable_heads()` in terms of `builtin_immutable_heads()`
* Warn if user redefines `builtin_immutable_heads()`, `mutable()` or
`immutable()`.
* Update module constant in revset_util.rs from BUILTIN_IMMUTABLE_HEADS
to USER_IMMUTABLE_HEADS to avoid confusion since it points at
`immutable_heads()` **and** we now have a revset-alias
literally named `builtin_immutable_heads()`.
* Add unittest
* Update CHANGELOG
* Update documentation.
Fixes: #4162
Still alias function shadows builtin function (of any arity) by name. This
allows to detect argument error as such, but might be a bit inconvenient if
user wants to overload heads() for example. If needed, maybe we can add some
config/revset syntax to import builtin function to alias namespace.
The functions table is keyed by name, not by (name, arity) pair. That's mainly
because std collections require keys to be Borrow, and a pair of borrowed
values is incompatible with owned pair. Another reason is it makes easy to look
up overloads by name.
Alias overloading could also be achieved by adding default parameters, but that
will complicate the implementation a bit more, and can't prevent shadowing of
0-ary immutable_heads().
Closes#2966
I'm going to reorganize "single"/"default_single" revset functions in a way
that resolve_single_rev_with_hint_about_all_prefix() is inlined.
evaluate_revset_to_single_commit() could be a private method of
WorkspaceCommandHelper, but I want to minimize the code that has to be hosted
there.
Many callers of resolve_revset() and evaluate_revset() will be migrated to
this wrapper. "single" and "default_single" APIs won't be replaced because
they require more contexts to construct error messages.
id_prefix_context() now uses bare revset::parse() to avoid dependency cycle.
Because the CLI error handler now prints error sources in multi-line format,
it doesn't make much sense to render Revset/TemplateParseError differently.
This patch also fixes the source() of the SyntaxError kind. It should be
self.pest_error.source() (= None), not self.pest_error.
It's inconsistent that some warnings have headings and some don't, and it seems
the choice is arbitrary. Let's unify the style. There are two exceptions:
1. continued line following labeled message,
2. "unrecognized response" followed by prompt.
AST substitution is technically closer to parsing, but the parsed expression
can be modified further by caller. So I think it's better to do optimize() in
later pass.
revset_util::parse() is inlined.
I just wanted to remove CommandError from parse_immutable_expression(), which
will be called from the templater, but the new error message looks also better.
Some of them will be called directly from the commit templater which shouldn't
know WorkspaceCommandHelper. All parameters are passed as function arguments
instead of having a nicer wrapper struct. That's because some resources (e.g.
repo and id prefix context) are also used for different purposes, and it seemed
uneasy to introduce high-level abstraction satisfying all the use cases.
