feat: oxidized progress bars

[bepri]

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Implements the progress_bar method for the emitter. This one has an entirely different API from the existing one, but comes with far more content.

The exact appearance of the progress bar doesn't need much review, as the design team and I have not landed on an approved appearance yet.

I strongly recommend reviewing per-commit.

Here's a script that showcases some of the new behavior and gives a good starting point for testing by hand:

import logging
from time import sleep

from craft_cli import Emitter, Verbosity

logger = logging.getLogger(__name__)
logger.setLevel(logging.DEBUG)

e = Emitter(Verbosity.BRIEF, "blah.log", "Hello", streaming_brief=True)
logger.info("Testing")

TOTAL_NUMBERS = 50
with e.progress_bar("Crunching the numbers", TOTAL_NUMBERS, show_progress=True, show_percentage=True) as prog:
    # An overflow just keeps counting over the total.
    for i in range(TOTAL_NUMBERS + 10):
        prog.tick()
        sleep(0.1)
        if i % 25 == 0:
            logger.warning("⚠️ Booping imminent ⚠️")
            sleep(0.1)
            prog.println("Boop")

    # Can't increment with a negative
    try:
        prog.inc(-1)
    except OverflowError as err:
        prog.println(f"Caught: {err}")
        prog.println("Phew, that was close.")

    # Can't use emitter methods while progress bar is active
    try:
        e.message("MOM SAID IT'S MY TURN WITH THE TTY")
    except RuntimeError as err:
        prog.println(f"Caught: {err}")
        prog.println("I get one more CPU cycle!")

e.message("Done")

CRAFT-4983

[bepri]

I found this refactor was necessary because the previous Message/MessageType model meant that all messages would require the same set of fields in a Message instance, even if their associated MessageType did not care about the fields. For example, a hypothetical MessageType::FinishProgressBar would never care about the Message.permanent field.

[bepri]

All of these unreachable!() blocks are such because the condition is already checked on the Printer. The reason it isn't checked here is that the InnerPrinter's thread ("printer thread" from here on) can panic and have its fail state not be noticed until the end of execution. From the main thread's side, this is only noticed at the end of execution when it tries to join the printer thread's handle again and discovers an error. Therefore, if we want an immediate error upon improper use, it has to originate from the main thread.

I'm not a huge fan of this architecture and would be happy to revisit it, but any alternative would've been well out of scope for this PR.

[bepri]

This macro allows the easy creation of builder-style object instantiation. In this particular use case, it converts the new method below into a method on Progresser called build, where each parameter of the method is instead a builder method.

This is a really common pattern in Rust that developers of this crate will expect, but the Python wrapper converts this builder pattern into a kwargs-based pattern for familiarity on the Python side.

[bepri]

See https://docs.rs/indicatif/0.18.3/indicatif/index.html#templates for an explanation of the keys used throughout this method

[mr-cal]

Looks nice overall!

Here's a few things:
If I raise an error midway through, it raises the error then prints a completed progress bar. I'd expect the progress bar to (1) not pretend it completed and (2) not print after an exception.

I'm also noticing the printing isn't deterministic. Look where boop is in these 3 consecutive runs:

I can only get it to print out of order in like 1 of 20 runs.

repro:

import logging
from time import sleep

from craft_cli import Emitter, Verbosity

logger = logging.getLogger(__name__)
logger.setLevel(logging.DEBUG)

e = Emitter(Verbosity.TRACE, "blah.log", "Hello", streaming_brief=True)
logger.info("Testing")

TOTAL_NUMBERS = 999
with e.progress_bar(
    "Crunching the numbers", TOTAL_NUMBERS, show_progress=True, show_percentage=True
) as prog:
    # An overflow just keeps counting over the total.
    for i in range(TOTAL_NUMBERS + 10):
        prog.tick()
        sleep(0.1)
        if i % 25 == 0:
            prog.inc(20)
            logger.warning("⚠️ Booping imminent ⚠️")
            sleep(0.1)
            prog.println("Boop")
            raise ValueError("boom")


e.message("Done")

And a last comment, should the println messages go to the log?

[bepri]

If I raise an error midway through, it raises the error then prints a completed progress bar. I'd expect the progress bar to (1) not pretend it completed and (2) not print after an exception.

I'm also noticing the printing isn't deterministic. Look where boop is in these 3 consecutive runs:

I fixed (1), but (2) and the nondeterministic printing I think are better handled in/after CRAFT-4985 (adding CraftError handling). I'll have to create a standardized way to raise errors and make sure the printing thread stops yapping before surfacing the traceback.

I'll take this as a win though. It ain't true multi-threaded programming unless there's nondeterminism.

[mr-cal]

LGTM!

[Copilot]

Pull request overview

Adds a new Rust-backed progress bar API to the Craft CLI emitter/printer pipeline, refactoring printer messages into a richer Event model to support progress bar lifecycle + printing while a bar is active.

Changes:

• Replaced the old Message/MessageType printer payload with Event + Text (and added progress-bar events).
• Implemented a new PyO3 Progresser context manager (Emitter.progress_bar(...)) backed by indicatif.
• Updated stream/log listeners to emit Event::Stream / Event::Log and added bon as a dependency.

Reviewed changes

Copilot reviewed 9 out of 10 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
src/printer.rs	Introduces Event model, progress-bar lifecycle handling, and routing/validation logic in Printer::send.
src/progress.rs	New PyO3 Progresser context manager and indicatif progress bar construction/printing APIs.
src/emitter.rs	Exposes Emitter.progress_bar(...) returning Progresser; updates emits to use Event::Text(Text).
src/streams.rs	Emits Event::Stream(Text) instead of the old Message struct.
src/logs.rs	Emits Event::Log(Text) instead of the old Message struct.
src/lib.rs	Registers the new Rust module (mod progress).
craft_cli/_rs/progress.pyi	Adds typing for the new Progresser API.
craft_cli/_rs/emitter.pyi	Adds typing for Emitter.progress_bar(...) -> Progresser.
Cargo.toml / Cargo.lock	Adds the bon dependency and locks transitive deps.

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