Failed to demangle defmt symbol ...: missing field `crate_name` when running probe-run 0.3.7 works with 0.3.6

[bplaat]

Describe the bug I have a small micro-controller Rust project that uses defmt and probe-run. It worked fine with probe-run 0.3.6. But when I want to run the program with cargo run --release with probe-run 0.3.7, I got this error:

Error: failed to demangle defmt symbol `{"package":"blink-rust","tag":"defmt_info","data":"Blink interval: {} ms","disambiguator":"11913491891077987529"}`: missing field `crate_name` at line 1 column 113

To Reproduce Steps to reproduce the behavior:

Example

1. Write src/main.rs

   
   #![no_std]
   #![no_main]

// ..

use {defmtrtt as , panicprobe as };

[entry]

fn main() -> ! { loop { defmt::info!("Test"); } }

2. Run it with `cargo run --release`

**Expected and observed behavior**
With `probe-run 0.3.6` this works fine but with `0.3.7` you get this error message:
```console
$ cargo run --release
    Finished release [optimized + debuginfo] target(s) in 0.24s
     Running `probe-run --chip STM32H743ZITx 'target\thumbv7em-none-eabihf\release\blink-rust'`
Error: failed to demangle defmt symbol `{"package":"blink-rust","tag":"defmt_info","data":"Blink interval: {} ms","disambiguator":"11913491891077987529"}`: missing field `crate_name` at line 1 column 113

config.toml The contents of your project's .cargo/config.toml file:

[target.thumbv7em-none-eabihf]
runner = 'probe-run --chip STM32H743VITx'
rustflags = [
  "-C", "link-arg=-Tlink.x",
  "-C", "link-arg=-Tdefmt.x",
]

[build]
target = "thumbv7em-none-eabihf"

[env]
DEFMT_LOG = "trace"

Cargo.toml The contents of your project's Cargo.toml file:

[package]
name = "blink-rust"
version = "0.1.0"
edition = "2021"
include = ["src/main.rs"]

[dependencies]
cortex-m = { version = "0.7.4", features = ["critical-section-single-core"] }
cortex-m-rt = "0.7.1"
stm32h7xx-hal = {version = "0.13.1", features = ["stm32h743v","rt"]}
panic-probe = { version = "0.3", features = ["print-rtt"] }
defmt = "0.3.3"
defmt-rtt = "0.4"

[profile.release]
codegen-units = 1
debug = 1
lto = 'fat'
opt-level = 'z'
overflow-checks = false

Probe details

$ probe-run --list-probes
the following probes were found:
[0]: STLink V2-1 (VID: 0483, PID: 374b, Serial: 0671FF525149787867184947, StLink)

Operating System: Windows, on WSL (Ubuntu) I get the same issue

Additional context Maybe I forgot something stupid or maybe the JSON symbol info really is missing a field :|

[Urhengulas]

This is because we changed the wire format but missed bumping the wire format version. Updating your defmt should fix this.

[Slushee-a]

The latest version of defmt on crates.io (0.3.4) still suffers from this issue. A temporary workaround is using the defmt repository directly.

defmt-rtt 0.4 requires defmt 0.3.4, so doing defmt = { git = ... } won't work. patch.crates-io can be used instead.

[dependencies]
defmt = "0.3.4"
defmt-rtt = "0.4"

[patch.crates-io]
defmt = { git = "https://github.com/knurling-rs/defmt" }

[Urhengulas]

https://github.com/knurling-rs/defmt/pull/750 adds backwards compatibility for wire format 3. This will get released soon.