Auto merge of #112849 - m-ou-se:panic-message-format, r=thomcc

Change default panic handler message format.

This changes the default panic hook's message format from:

```
thread '{thread}' panicked at '{message}', {location}
```

to

```
thread '{thread}' panicked at {location}:
{message}
```

This puts the message on its own line without surrounding quotes, making it easiser to read. For example:

Before:
```
thread 'main' panicked at 'env variable `IMPORTANT_PATH` should be set by `wrapper_script.sh`', src/main.rs:4:6
```
After:
```
thread 'main' panicked at src/main.rs:4:6:
env variable `IMPORTANT_PATH` should be set by `wrapper_script.sh`
```

---

See this PR by `@nyurik,` which does that for only multi-line messages (specifically because of `assert_eq`): rust-lang/rust#111071

This is the change that does that for *all* panic messages.

Author: bors

tests/fail/concurrency/unwind_top_of_stack.stderr

@@ -1,4 +1,5 @@
-thread '<unnamed>' panicked at 'explicit panic', $DIR/unwind_top_of_stack.rs:LL:CC
+thread '<unnamed>' panicked at $DIR/unwind_top_of_stack.rs:LL:CC:
+explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 error: Undefined Behavior: unwinding past the topmost frame of the stack
   --> $DIR/unwind_top_of_stack.rs:LL:CC

tests/fail/function_calls/exported_symbol_bad_unwind1.stderr

@@ -1,4 +1,5 @@
-thread 'main' panicked at 'explicit panic', $DIR/exported_symbol_bad_unwind1.rs:LL:CC
+thread 'main' panicked at $DIR/exported_symbol_bad_unwind1.rs:LL:CC:
+explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 error: Undefined Behavior: unwinding past a stack frame that does not allow unwinding
   --> $DIR/exported_symbol_bad_unwind1.rs:LL:CC

tests/fail/function_calls/exported_symbol_bad_unwind2.both.stderr

@@ -1,4 +1,5 @@
-thread 'main' panicked at 'explicit panic', $DIR/exported_symbol_bad_unwind2.rs:LL:CC
+thread 'main' panicked at $DIR/exported_symbol_bad_unwind2.rs:LL:CC:
+explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 error: abnormal termination: panic in a function that cannot unwind
   --> $DIR/exported_symbol_bad_unwind2.rs:LL:CC

tests/fail/function_calls/exported_symbol_bad_unwind2.definition.stderr

@@ -1,4 +1,5 @@
-thread 'main' panicked at 'explicit panic', $DIR/exported_symbol_bad_unwind2.rs:LL:CC
+thread 'main' panicked at $DIR/exported_symbol_bad_unwind2.rs:LL:CC:
+explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 error: abnormal termination: panic in a function that cannot unwind
   --> $DIR/exported_symbol_bad_unwind2.rs:LL:CC

tests/fail/function_calls/exported_symbol_bad_unwind2.extern_block.stderr

@@ -1,4 +1,5 @@
-thread 'main' panicked at 'explicit panic', $DIR/exported_symbol_bad_unwind2.rs:LL:CC
+thread 'main' panicked at $DIR/exported_symbol_bad_unwind2.rs:LL:CC:
+explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 error: Undefined Behavior: unwinding past a stack frame that does not allow unwinding
   --> $DIR/exported_symbol_bad_unwind2.rs:LL:CC

tests/fail/panic/bad_unwind.stderr

@@ -1,4 +1,5 @@
-thread 'main' panicked at 'explicit panic', $DIR/bad_unwind.rs:LL:CC
+thread 'main' panicked at $DIR/bad_unwind.rs:LL:CC:
+explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 error: Undefined Behavior: unwinding past a stack frame that does not allow unwinding
   --> $DIR/bad_unwind.rs:LL:CC

tests/fail/panic/double_panic.stderr

@@ -1,6 +1,8 @@
-thread 'main' panicked at 'first', $DIR/double_panic.rs:LL:CC
+thread 'main' panicked at $DIR/double_panic.rs:LL:CC:
+first
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
-thread 'main' panicked at 'second', $DIR/double_panic.rs:LL:CC
+thread 'main' panicked at $DIR/double_panic.rs:LL:CC:
+second
 stack backtrace:
 error: abnormal termination: panic in a function that cannot unwind
   --> $DIR/double_panic.rs:LL:CC

tests/fail/panic/no_std.stderr

@@ -1,4 +1,5 @@
-panicked at 'blarg I am dead', $DIR/no_std.rs:LL:CC
+panicked at $DIR/no_std.rs:LL:CC:
+blarg I am dead
 error: abnormal termination: the program aborted execution
   --> $DIR/no_std.rs:LL:CC
    |

tests/fail/panic/panic_abort1.stderr

@@ -1,4 +1,5 @@
-thread 'main' panicked at 'panicking from libstd', $DIR/panic_abort1.rs:LL:CC
+thread 'main' panicked at $DIR/panic_abort1.rs:LL:CC:
+panicking from libstd
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 error: abnormal termination: the program aborted execution
   --> RUSTLIB/panic_abort/src/lib.rs:LL:CC

tests/fail/panic/panic_abort2.stderr

@@ -1,4 +1,5 @@
-thread 'main' panicked at '42-panicking from libstd', $DIR/panic_abort2.rs:LL:CC
+thread 'main' panicked at $DIR/panic_abort2.rs:LL:CC:
+42-panicking from libstd
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 error: abnormal termination: the program aborted execution
   --> RUSTLIB/panic_abort/src/lib.rs:LL:CC

tests/fail/panic/panic_abort3.stderr

@@ -1,4 +1,5 @@
-thread 'main' panicked at 'panicking from libcore', $DIR/panic_abort3.rs:LL:CC
+thread 'main' panicked at $DIR/panic_abort3.rs:LL:CC:
+panicking from libcore
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 error: abnormal termination: the program aborted execution
   --> RUSTLIB/panic_abort/src/lib.rs:LL:CC

tests/fail/panic/panic_abort4.stderr

@@ -1,4 +1,5 @@
-thread 'main' panicked at '42-panicking from libcore', $DIR/panic_abort4.rs:LL:CC
+thread 'main' panicked at $DIR/panic_abort4.rs:LL:CC:
+42-panicking from libcore
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 error: abnormal termination: the program aborted execution
   --> RUSTLIB/panic_abort/src/lib.rs:LL:CC

tests/fail/panic/thread_local_const_drop_panic.stderr

@@ -1,4 +1,5 @@
-thread $NAME panicked at 'ow', $DIR/thread_local_const_drop_panic.rs:LL:CC
+thread $NAME panicked at $DIR/thread_local_const_drop_panic.rs:LL:CC:
+ow
 fatal runtime error: thread local panicked on drop
 error: abnormal termination: the program aborted execution
 

tests/fail/panic/thread_local_drop_panic.stderr

@@ -1,4 +1,5 @@
-thread $NAME panicked at 'ow', $DIR/thread_local_drop_panic.rs:LL:CC
+thread $NAME panicked at $DIR/thread_local_drop_panic.rs:LL:CC:
+ow
 fatal runtime error: thread local panicked on drop
 error: abnormal termination: the program aborted execution
 

tests/fail/terminate-terminator.stderr

@@ -1,6 +1,7 @@
 warning: You have explicitly enabled MIR optimizations, overriding Miri's default which is to completely disable them. Any optimizations may hide UB that Miri would otherwise detect, and it is not necessarily possible to predict what kind of UB will be missed. If you are enabling optimizations to make Miri run faster, we advise using cfg(miri) to shrink your workload instead. The performance benefit of enabling MIR optimizations is usually marginal at best.
 
-thread 'main' panicked at 'explicit panic', $DIR/terminate-terminator.rs:LL:CC
+thread 'main' panicked at $DIR/terminate-terminator.rs:LL:CC:
+explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 error: abnormal termination: panic in a function that cannot unwind
   --> $DIR/terminate-terminator.rs:LL:CC

tests/fail/unwind-action-terminate.stderr

@@ -1,4 +1,5 @@
-thread 'main' panicked at 'explicit panic', $DIR/unwind-action-terminate.rs:LL:CC
+thread 'main' panicked at $DIR/unwind-action-terminate.rs:LL:CC:
+explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 error: abnormal termination: panic in a function that cannot unwind
   --> $DIR/unwind-action-terminate.rs:LL:CC

tests/panic/div-by-zero-2.stderr

@@ -1,2 +1,3 @@
-thread 'main' panicked at 'attempt to divide by zero', $DIR/div-by-zero-2.rs:LL:CC
+thread 'main' panicked at $DIR/div-by-zero-2.rs:LL:CC:
+attempt to divide by zero
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

tests/panic/function_calls/exported_symbol_good_unwind.stderr

@@ -1,4 +1,7 @@
-thread 'main' panicked at 'explicit panic', $DIR/exported_symbol_good_unwind.rs:LL:CC
+thread 'main' panicked at $DIR/exported_symbol_good_unwind.rs:LL:CC:
+explicit panic
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
-thread 'main' panicked at 'explicit panic', $DIR/exported_symbol_good_unwind.rs:LL:CC
-thread 'main' panicked at 'explicit panic', $DIR/exported_symbol_good_unwind.rs:LL:CC
+thread 'main' panicked at $DIR/exported_symbol_good_unwind.rs:LL:CC:
+explicit panic
+thread 'main' panicked at $DIR/exported_symbol_good_unwind.rs:LL:CC:
+explicit panic

tests/panic/oob_subslice.stderr

@@ -1,2 +1,3 @@
-thread 'main' panicked at 'range end index 5 out of range for slice of length 4', $DIR/oob_subslice.rs:LL:CC
+thread 'main' panicked at $DIR/oob_subslice.rs:LL:CC:
+range end index 5 out of range for slice of length 4
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

tests/panic/overflowing-lsh-neg.stderr

@@ -1,2 +1,3 @@
-thread 'main' panicked at 'attempt to shift left with overflow', $DIR/overflowing-lsh-neg.rs:LL:CC
+thread 'main' panicked at $DIR/overflowing-lsh-neg.rs:LL:CC:
+attempt to shift left with overflow
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

tests/panic/overflowing-rsh-1.stderr

@@ -1,2 +1,3 @@
-thread 'main' panicked at 'attempt to shift right with overflow', $DIR/overflowing-rsh-1.rs:LL:CC
+thread 'main' panicked at $DIR/overflowing-rsh-1.rs:LL:CC:
+attempt to shift right with overflow
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

tests/panic/overflowing-rsh-2.stderr

@@ -1,2 +1,3 @@
-thread 'main' panicked at 'attempt to shift right with overflow', $DIR/overflowing-rsh-2.rs:LL:CC
+thread 'main' panicked at $DIR/overflowing-rsh-2.rs:LL:CC:
+attempt to shift right with overflow
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

tests/panic/panic1.stderr

@@ -1,4 +1,5 @@
-thread 'main' panicked at 'panicking from libstd', $DIR/panic1.rs:LL:CC
+thread 'main' panicked at $DIR/panic1.rs:LL:CC:
+panicking from libstd
 stack backtrace:
    0: std::panicking::begin_panic_handler
  at RUSTLIB/std/src/panicking.rs:LL:CC

tests/panic/panic2.stderr

@@ -1,2 +1,3 @@
-thread 'main' panicked at '42-panicking from libstd', $DIR/panic2.rs:LL:CC
+thread 'main' panicked at $DIR/panic2.rs:LL:CC:
+42-panicking from libstd
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

tests/panic/panic3.stderr

@@ -1,2 +1,3 @@
-thread 'main' panicked at 'panicking from libcore', $DIR/panic3.rs:LL:CC
+thread 'main' panicked at $DIR/panic3.rs:LL:CC:
+panicking from libcore
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

tests/panic/panic4.stderr

@@ -1,2 +1,3 @@
-thread 'main' panicked at '42-panicking from libcore', $DIR/panic4.rs:LL:CC
+thread 'main' panicked at $DIR/panic4.rs:LL:CC:
+42-panicking from libcore
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

tests/panic/transmute_fat2.stderr

@@ -1,2 +1,3 @@
-thread 'main' panicked at 'index out of bounds: the len is 0 but the index is 0', $DIR/transmute_fat2.rs:LL:CC
+thread 'main' panicked at $DIR/transmute_fat2.rs:LL:CC:
+index out of bounds: the len is 0 but the index is 0
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

tests/panic/unsupported_foreign_function.stderr

@@ -1,2 +1,3 @@
-thread 'main' panicked at 'unsupported Miri functionality: can't call foreign function `foo` on $OS', $DIR/unsupported_foreign_function.rs:LL:CC
+thread 'main' panicked at $DIR/unsupported_foreign_function.rs:LL:CC:
+unsupported Miri functionality: can't call foreign function `foo` on $OS
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

tests/panic/unsupported_syscall.stderr

@@ -1,2 +1,3 @@
-thread 'main' panicked at 'unsupported Miri functionality: can't execute syscall with ID 0', $DIR/unsupported_syscall.rs:LL:CC
+thread 'main' panicked at $DIR/unsupported_syscall.rs:LL:CC:
+unsupported Miri functionality: can't execute syscall with ID 0
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

tests/pass/concurrency/simple.stderr

@@ -1,3 +1,5 @@
-thread '<unnamed>' panicked at 'Hello!', $DIR/simple.rs:LL:CC
+thread '<unnamed>' panicked at $DIR/simple.rs:LL:CC:
+Hello!
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
-thread 'childthread' panicked at 'Hello, world!', $DIR/simple.rs:LL:CC
+thread 'childthread' panicked at $DIR/simple.rs:LL:CC:
+Hello, world!

tests/pass/panic/catch_panic.stderr

@@ -1,24 +1,35 @@
-thread 'main' panicked at 'Hello from panic: std', $DIR/catch_panic.rs:LL:CC
+thread 'main' panicked at $DIR/catch_panic.rs:LL:CC:
+Hello from panic: std
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 Caught panic message (&str): Hello from panic: std
-thread 'main' panicked at 'Hello from panic: 1', $DIR/catch_panic.rs:LL:CC
+thread 'main' panicked at $DIR/catch_panic.rs:LL:CC:
+Hello from panic: 1
 Caught panic message (String): Hello from panic: 1
-thread 'main' panicked at 'Hello from panic: 2', $DIR/catch_panic.rs:LL:CC
+thread 'main' panicked at $DIR/catch_panic.rs:LL:CC:
+Hello from panic: 2
 Caught panic message (String): Hello from panic: 2
-thread 'main' panicked at 'Box<dyn Any>', $DIR/catch_panic.rs:LL:CC
+thread 'main' panicked at $DIR/catch_panic.rs:LL:CC:
+Box<dyn Any>
 Failed to get caught panic message.
-thread 'main' panicked at 'Hello from panic: core', $DIR/catch_panic.rs:LL:CC
+thread 'main' panicked at $DIR/catch_panic.rs:LL:CC:
+Hello from panic: core
 Caught panic message (&str): Hello from panic: core
-thread 'main' panicked at 'Hello from panic: 5', $DIR/catch_panic.rs:LL:CC
+thread 'main' panicked at $DIR/catch_panic.rs:LL:CC:
+Hello from panic: 5
 Caught panic message (String): Hello from panic: 5
-thread 'main' panicked at 'index out of bounds: the len is 3 but the index is 4', $DIR/catch_panic.rs:LL:CC
+thread 'main' panicked at $DIR/catch_panic.rs:LL:CC:
+index out of bounds: the len is 3 but the index is 4
 Caught panic message (String): index out of bounds: the len is 3 but the index is 4
-thread 'main' panicked at 'attempt to divide by zero', $DIR/catch_panic.rs:LL:CC
+thread 'main' panicked at $DIR/catch_panic.rs:LL:CC:
+attempt to divide by zero
 Caught panic message (&str): attempt to divide by zero
-thread 'main' panicked at 'align_offset: align is not a power-of-two', RUSTLIB/core/src/ptr/const_ptr.rs:LL:CC
+thread 'main' panicked at RUSTLIB/core/src/ptr/const_ptr.rs:LL:CC:
+align_offset: align is not a power-of-two
 Caught panic message (&str): align_offset: align is not a power-of-two
-thread 'main' panicked at 'assertion failed: false', $DIR/catch_panic.rs:LL:CC
+thread 'main' panicked at $DIR/catch_panic.rs:LL:CC:
+assertion failed: false
 Caught panic message (&str): assertion failed: false
-thread 'main' panicked at 'assertion failed: false', $DIR/catch_panic.rs:LL:CC
+thread 'main' panicked at $DIR/catch_panic.rs:LL:CC:
+assertion failed: false
 Caught panic message (&str): assertion failed: false
 Success!

tests/pass/panic/concurrent-panic.stderr

@@ -1,10 +1,12 @@
 Thread 1 starting, will block on mutex
 Thread 1 reported it has started
-thread '<unnamed>' panicked at 'panic in thread 2', $DIR/concurrent-panic.rs:LL:CC
+thread '<unnamed>' panicked at $DIR/concurrent-panic.rs:LL:CC:
+panic in thread 2
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 Thread 2 blocking on thread 1
 Thread 2 reported it has started
 Unlocking mutex
-thread '<unnamed>' panicked at 'panic in thread 1', $DIR/concurrent-panic.rs:LL:CC
+thread '<unnamed>' panicked at $DIR/concurrent-panic.rs:LL:CC:
+panic in thread 1
 Thread 1 has exited
 Thread 2 has exited

tests/pass/panic/nested_panic_caught.stderr

@@ -1,4 +1,6 @@
-thread 'main' panicked at 'once', $DIR/nested_panic_caught.rs:LL:CC
+thread 'main' panicked at $DIR/nested_panic_caught.rs:LL:CC:
+once
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
-thread 'main' panicked at 'twice', $DIR/nested_panic_caught.rs:LL:CC
+thread 'main' panicked at $DIR/nested_panic_caught.rs:LL:CC:
+twice
 stack backtrace: