Allow allocations during most panics

The panic logger is allowed to allocate now. If a panic message uses
string formatting then that may still trigger `assert_no_alloc`.

Cargo.lock

@@ -2118,16 +2118,6 @@ dependencies = [
  "value-bag",
 ]
 
-[[package]]
-name = "log-panics"
-version = "2.0.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ae0136257df209261daa18d6c16394757c63e032e27aafd8b07788b051082bef"
-dependencies = [
- "backtrace",
- "log",
-]
-
 [[package]]
 name = "loudness_war_winner"
 version = "0.1.0"
@@ -2387,6 +2377,7 @@ dependencies = [
  "assert_no_alloc",
  "atomic_float",
  "atomic_refcell",
+ "backtrace",
  "baseview 0.1.0 (git+https://github.com/robbert-vdh/baseview.git?branch=feature/resize)",
  "bitflags",
  "cfg-if 1.0.0",
@@ -2397,7 +2388,6 @@ dependencies = [
  "lazy_static",
  "libc",
  "log",
- "log-panics",
  "midi-consts",
  "nih_plug_derive",
  "parking_lot 0.12.1",

Cargo.toml

@@ -64,13 +64,13 @@ nih_plug_derive = { path = "nih_plug_derive" }
 
 atomic_float = "0.1"
 atomic_refcell = "0.1"
+backtrace = "0.3.65"
 bitflags = "1.3"
 cfg-if = "1.0"
 clap-sys = "0.1"
 crossbeam = "0.8"
 lazy_static = "1.4"
 log = { version = "0.4", features = ["std", "release_max_level_info"] }
-log-panics = { version = "2.0", features = ["with-backtrace"] }
 midi-consts = "0.1"
 parking_lot = "0.12"
 raw-window-handle = "0.4"

src/wrapper/util.rs

@@ -1,9 +1,12 @@
+use backtrace::Backtrace;
 use std::cmp;
 use std::fs::File;
 use std::marker::PhantomData;
 use std::os::raw::c_char;
 use std::sync::atomic::{AtomicBool, Ordering};
 
+use crate::util::permit_alloc;
+
 /// The environment variable for controlling the logging behavior.
 const NIH_LOG_ENV: &str = "NIH_LOG";
 
@@ -123,7 +126,48 @@ pub fn setup_logger() {
         }
     }
 
-    log_panics::init();
+    // This is copied from same as the `log_panics` crate, but it's wrapped in `permit_alloc()`.
+    // Otherwise logging panics will trigger `assert_no_alloc` as this also allocates.
+    std::panic::set_hook(Box::new(|info| {
+        permit_alloc(|| {
+            // All of this is directly copied from `permit_no_alloc`, except that `error!()` became
+            // `nih_error!()` and `Shim` has been inlined
+            let backtrace = Backtrace::new();
+
+            let thread = std::thread::current();
+            let thread = thread.name().unwrap_or("unnamed");
+
+            let msg = match info.payload().downcast_ref::<&'static str>() {
+                Some(s) => *s,
+                None => match info.payload().downcast_ref::<String>() {
+                    Some(s) => &**s,
+                    None => "Box<Any>",
+                },
+            };
+
+            match info.location() {
+                Some(location) => {
+                    nih_error!(
+                        target: "panic", "thread '{}' panicked at '{}': {}:{}\n{:?}",
+                        thread,
+                        msg,
+                        location.file(),
+                        location.line(),
+                        backtrace
+                    );
+                }
+                None => {
+                    nih_error!(
+                        target: "panic",
+                        "thread '{}' panicked at '{}'\n{:?}",
+                        thread,
+                        msg,
+                        backtrace
+                    )
+                }
+            }
+        })
+    }));
 }
 
 /// A wrapper around the entire process function, including the plugin wrapper parts. This sets up