Before:
- `bool`: a flag
- `Option<_>`: not required
- `Option<Option<_>>` is not required and when it is present, the value
is not required
- `Vec<_>`: multiple values, optional
- `Option<Vec<_>>`: multiple values, min values of 0, optional
After:
- `bool`: a flag
- `Option<_>`: not required
- `Option<Option<_>>` is not required and when it is present, the value
is not required
- `Vec<_>`: multiple occurrences, optional
- optional: `Vec` implies 0 or more, so should not imply required
- `Option<Vec<_>>`: multiple occurrences, optional
- optional: Use over `Vec` to detect when no option being present when
using multiple values
Motivations:
My priorities were:
1. Are we getting in the users way?
2. Does the API make sense?
3. Does the API encourage best practices?
I was originally concerned about the lack of composability with
`Option<Option<_>>` and `Option<Vec<_>>` (and eventually `Vec<Vec<_>>`).
It prescribes special meaning to each type depending on where it shows
up, rather than providing a single meaning for a type generally. You
then can't do things like have `Option<_>` mean "required argument with
optional value" without hand constructing it. However, in practice the
outer type correlates with the argument occurrence and the inner type
with the value. It is rare to want the value behavior without also the
occurrence behavior. So I figure it is probably fine as long as people
can set the flags to manually get the behavior they want.
`Vec<_>` implies multiple occurrences, rather than multiple values.
Anecdotally, whenever I've used the old `Arg::multiple`, I thought I was
getting `Arg::multiple_occurrences` only. `Arg::multiple_values`,
without any bounds or delimiter requirement, can lead to a confusing
user experience and isn't a good default for these. On top of that, if
someone does have an unbounded or a delimiter multiple values, they are
probably also using multiple occurrences.
`Vec<_>` is optional because a `Vec` implies 0 or more, so we stick to
the meaning of the rust type. At least for me, I also rarely need a
required with multiple occurrences argument but more often need optional
with multiple occurrences.
`Option<Vec<_>>` ends up matching `Vec<_>` which can raise the question
of why have it. Some users might prefer the type. Otherwise, this is
so users can detect whether the argument is present or not when using
`min_values(0)`. Rather than defining an entire policy around this and
having users customize it, or setting `min_values(0)` without the rest
of a default policy, this gives people a blank slate to work from.
Another design option would have been to not infer any special-type
settings if someone sets a handful of settings manually, which would
have avoided the confusion in Issue clap-rs/clap 2599 but I see that
being confusing (for someone who knows the default, they will be
expecting it to be additive; which flags disable inferred settings?) and
brittle (as flags are added or changed, how do we ensure we keep this
up?).
Tests were added to ensure we support people customizing the behavior to
match their needs.
This is not solving:
- `Vec<Vec<_>>`, see clap-rs/clap 2924
- `(T1, T2)`, `Vec<(T1, T2)>`, etc, see clap-rs/clap 1717
- `Vec<Option<_>>` and many other potential combinations
Fixes clap-rs/clap 1772
Fixes clap-rs/clap 2599
See also clap-rs/clap 2195
This reverts commits 24cb8b1..d0abb37 from clap-rs/clap#1840
This is part of #16. clap-rs/clap#1840 wasn't the right call but we
don't have time to make the decision now, so instead of having one
option and changing it in 4.0, this reverts back to clap2 behavior.
In experimenting on #1772, I want to write test cases for various
combinations of required or not, values vs occurrences, etc. There
wasn't really a clear place to put these.
On top of that, I wanted there to be a clear place in the tests for
describing the behavior of special types, to make it easier to audit and
easier to see how a PR for #1772 changes things.
As part of this effort in organizing these tests, I reduced the number
of tests that use special types. This better focuses these tests on the
cases they are intending to cover, rather than pulling in unrelated
features. This makes it easier to audit special types and makes it so
failures give more focused results, making it easier to see what broke.
The tests are using `to_string` which maps to `Display::fmt` and the
`Colorizer` version is colorless. To get color, it is only supported
with `print()` which has to go to stdout / stderr and can't be directed
to an arbitrary stream.
`Parser::parse_from` will call `exit` on failure and we don't just lose
backtrace information but we don't even know which of the tests running
in parallel panicked. I ran into this when experimenting with
`clap_derive` and I couldn't tell what actually failed.
So let's switch to `Parse::try_parse_from`.
Errors went from:
```
test option_option ... ok
error: Found argument 'bar' which wasn't expected, or isn't valid in this context
USAGE:
clap_derive [OPTIONS]
For more information try --help
error: test failed, to rerun pass '--test arg_enum'
```
To:
```
test option_option ... ok
test variant_with_defined_casing ... ok
test skip_variant ... ok
test default_value ... ok
test vector ... FAILED
test option_vector ... ok
failures:
---- vector stdout ----
thread 'vector' panicked at 'called `Result::unwrap()` on an `Err` value: Error { message: Formatted(Colorizer { use_stderr: true, color_when: Auto
, pieces: [("error:", Some(Red)), (" ", None), ("Found argument '", None), ("bar", Some(Yellow)), ("' which wasn't expected, or isn't valid in this
context", None), ("\n\n", None), ("USAGE:\n clap_derive [OPTIONS]", None), ("\n\nFor more information try ", None), ("--help", Some(Green)), ("
\n", None)] }), kind: UnknownArgument, info: ["bar"], source: None, backtrace: Backtrace }', clap_derive/tests/arg_enum.rs:388:56
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
failures:
vector
test result: FAILED. 15 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
error: test failed, to rerun pass '--test arg_enum'
```
This is to help verify behavior added in #2943. We separated the error
raising site from the error formatting site and this verifies that the
formatting actually happens.
When an anonymous struct is inside of an enum, we end up applying the
App methods twice, once for the `augment_args` and once for variant.
This consolidates those calls.
Fixes#2898
Due to a copy/paste bug, we were reading the `help_heading` for
Subcommands from the enum's attribute and not the variant's attribute.
It doesn't make sense for the outer command's help_heading to control
the subcommands help_heading.
This does raise an interesting question on inheriting / propagating help_heading,
which I originally wrote the tests for. We'd first need to answer
whether it should be built-in to the builder or derive-specific.
In working on converting unwraps to errors, I noticed that we did not
spport `arg_enum` for `Option<Option<_>>` and `Option<Vec<_>>`, so this
addresses that.
My main motivation was to consolidate and make the logic more
consistent, the bug fix just fell out of that work.
In considering potential work for #2683, I realized we might need a type to carry data for
each of the `multiple_values`. `ArgValue` works both for that and for
possible values, so we need to come up with a better name for one or
both. Changing `ArgValue`s name now would be ideal since its new in
clap3 and by renaming it, we can reduce churn for users.
While thinking about this, I realized I regularly get these mixed
up, so renaming `ArgValue` to `PossibleValue` I think will help clear
things up, regardless of #2683.
Before, when `flatten`ing, the struct you flattened in could set the
help heading for all the following arguments. Now, we scope each
`flatten` to not do that.
I had originally intended to bake this into the initial / final methods
but that would have required some re-work to allow capturing state
between them that seemed unnecessary.
Fixes#2803
We normally set all app attributes at the end. This can be changed but
will require some work to ensure
- Top-level item's doc cmment ins our over flattened
- We still support `Args` / `Subcommand` be used to initialize an `App` when
creating a subcommand
In the mean time, this special cases `help_heading` to happen first.
We'll need this special casing anyways to address #2803 since we'll need
to capture the old help heading before addings args and then restore it
after. I guess we could unconditionally do that but its extra work /
boilerplate for when people have to dig into their what the derives do.
Fixes#2785
When working on #2803, I noticed a disprecancy in the augment
behavior between `Arg`s and `Subcommand`s that makes it so `Arg`s can't
be flattened with the update functionality.
For those that want the original behavior, you can usxe
`arg.help_heading(Some("FLAGS"))` on your flags. Limitations:
- This will not give you a special sort order
- This will not get a `[FLAGS]` added to usage
For templates, we removed `{unified}` and `{flags}`. To help people
catch these, a debug_assert was added.
I'm unsure but I think there might be a change in behavior in calcuating
when to show `[OPTION]` in usage. The old code only looked at
`required` while flags looked only at arg groups. We now look at both.
Ideally we'd add these in `_build` and remove special casing for
no-groups except in the sort order of groups. I feel like thats best
left for later.
This also reduced the scope of `App`s public API.
`get_*_with_no_heading` seemed a bit specialized to be in the public
API. #2853 looks at splitting it out into its own PR.
BREAKING CHANGE: Multiple
- `UnifiedHelpMessage` removed
- `{flags}` and `{unified}` are removed and will assert when present.
- `get_*_with_no_heading` removed
Fixes#2807
A lot of users expected `color` feature flag and `ColorAuto` etc to
control all colors. Having this extra flag around is easy to miss and
adds to our overall settings bloat, making it harder to find settings
people want.
This completely removes it, rather than make it deprecated like
functions in #2617, because there is extra work to mark things
deprecated as Settings and we should decide on our strategy first before
investing time in addressing that issue.
Fixes#2806
Before #2005, `Clap` was a special trait that derived all clap traits it
detected were relevant (including an enum getting both `ArgEnum`,
`Clap`, and `Subcommand`). Now, we have elevated `Clap`, `Args`,
`Subcommand`, and `ArgEnum` to be user facing but the name `Clap` isn't
very descriptive.
This also helps further clarify the relationships so a crate providing
an item to be `#[clap(flatten)]` or `#[clap(subcommand)]` is more likely
to choose the needed trait to derive.
Also, my proposed fix fo #2785 includes making `App` attributes almost
exclusively for `Clap`. Clarifying the names/roles will help
communicate this.
For prior discussion, see #2583
2823: fix(derive): Subcommands not working within macro_rules r=epage a=epage
2824: docs(derive): Fix explanation on optional string list argument r=epage a=epage
2827: feat: Add backtraces to errors r=epage a=epage
Co-authored-by: Ed Page <eopage@gmail.com>
2821: test(derive): Port structopt flatten coverage r=epage a=epage
2822: feat(derive): Add support for lower/upper in rename_all r=epage a=epage
Co-authored-by: Ed Page <eopage@gmail.com>
This carries over a test case from
https://github.com/TeXitoi/structopt/pull/448, and re-fixes it according
to the changes we've made since we forked. I also tried to identify
other cases and quote them to avoid playing whack-a-mole with this.
This is a part of #2809
Some programs do not use anything to separate word boundaries.
For example a struct may contain the field `build_dir` while the flag is
`--builddir`.
This is a port of https://github.com/TeXitoi/structopt/pull/412
This is part of #2809
Before there was no way to make `SubcommandsNegateReqs` with
`clap_derive` because it required a required field with a sentinel value
for when the required part was negated. We blocked that.
This turned out simpler than I expected.
This came out of the discussion for #2255 but that issue is more
specifically about the panic, so not closing it.
Before, validating UTF-8 was all-or-nothing and would cause a `panic` if
someone used the right API with non-UTF-8 input.
Now, all arguments are validated for UTF-8, unless opted-out. This
ensures a non-panicing path forward at the cost of people using the
builder API that previously did `value_of_os` need to now set this flag.
Fixes#751
Right now
- `default_value="something"` is a raw method
- `default_value` uses native types
This commit splits the meanings
- `default_value="something"` is a raw method
- `default_value_t` uses `T::default()`
- `default_value_t=expr` uses an expression that evaluates to `T`
This is meant to mirror the `value_of` / `value_of_t` API.
At the moment, this is limited to `T: Display` to work with clap's
default system. Something we can look at in the future is a way to
loosen that restriction. One quick win is to specialize when `arg_enum`
is set. The main downside is complicating the processing of attributes
because it then means we need some processed before others.
Since this builds on `clap`s existing default system, this also means
users do not get any performance gains out of using `default_value_t`,
since we still need to parse it but we also need to convert it to a
string.
Fixes#1694
