release notes: 2.21.0

This commit is contained in:
Eelco Dolstra 2024-03-11 16:22:29 +01:00
parent 0ce58cd1c2
commit b12dc76cfc
23 changed files with 367 additions and 414 deletions

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@ -1,9 +0,0 @@
---
synopsis: "CLI options `--arg-from-file` and `--arg-from-stdin`"
prs: 10122
---
The new CLI option `--arg-from-file` *name* *path* passes the contents
of file *path* as a string value via the function argument *name* to a
Nix expression. Similarly, the new option `--arg-from-stdin` *name*
reads the contents of the string from standard input.

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@ -1,40 +0,0 @@
---
synopsis: Concise error printing in `nix repl`
prs: 9928
---
Previously, if an element of a list or attribute set threw an error while
evaluating, `nix repl` would print the entire error (including source location
information) inline. This output was clumsy and difficult to parse:
```
nix-repl> { err = builtins.throw "uh oh!"; }
{ err = «error:
… while calling the 'throw' builtin
at «string»:1:9:
1| { err = builtins.throw "uh oh!"; }
| ^
error: uh oh!»; }
```
Now, only the error message is displayed, making the output much more readable.
```
nix-repl> { err = builtins.throw "uh oh!"; }
{ err = «error: uh oh!»; }
```
However, if the whole expression being evaluated throws an error, source
locations and (if applicable) a stack trace are printed, just like you'd expect:
```
nix-repl> builtins.throw "uh oh!"
error:
… while calling the 'throw' builtin
at «string»:1:1:
1| builtins.throw "uh oh!"
| ^
error: uh oh!
```

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@ -1,9 +0,0 @@
---
synopsis: "`--debugger` can now access bindings from `let` expressions"
prs: 9918
issues: 8827.
---
Breakpoints and errors in the bindings of a `let` expression can now access
those bindings in the debugger. Previously, only the body of `let` expressions
could access those bindings.

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@ -1,9 +0,0 @@
---
synopsis: Enter the `--debugger` when `builtins.trace` is called if `debugger-on-trace` is set
prs: 9914
---
If the `debugger-on-trace` option is set and `--debugger` is given,
`builtins.trace` calls will behave similarly to `builtins.break` and will enter
the debug REPL. This is useful for determining where warnings are being emitted
from.

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@ -1,25 +0,0 @@
---
synopsis: Debugger prints source position information
prs: 9913
---
The `--debugger` now prints source location information, instead of the
pointers of source location information. Before:
```
nix-repl> :bt
0: while evaluating the attribute 'python311.pythonForBuild.pkgs'
0x600001522598
```
After:
```
0: while evaluating the attribute 'python311.pythonForBuild.pkgs'
/nix/store/hg65h51xnp74ikahns9hyf3py5mlbbqq-source/overrides/default.nix:132:27
131|
132| bootstrappingBase = pkgs.${self.python.pythonAttr}.pythonForBuild.pkgs;
| ^
133| in
```

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@ -1,25 +0,0 @@
---
synopsis: The `--debugger` will start more reliably in `let` expressions and function calls
prs: 9917
issues: 6649
---
Previously, if you attempted to evaluate this file with the debugger:
```nix
let
a = builtins.trace "before inner break" (
builtins.break "hello"
);
b = builtins.trace "before outer break" (
builtins.break a
);
in
b
```
Nix would correctly enter the debugger at `builtins.break a`, but if you asked
it to `:continue`, it would skip over the `builtins.break "hello"` expression
entirely.
Now, Nix will correctly enter the debugger at both breakpoints.

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@ -1,14 +0,0 @@
---
synopsis: Fix a FOD sandbox escape
issues:
prs:
---
Cooperating Nix derivations could send file descriptors to files in the Nix
store to each other via Unix domain sockets in the abstract namespace. This
allowed one derivation to modify the output of the other derivation, after Nix
has registered the path as "valid" and immutable in the Nix database.
In particular, this allowed the output of fixed-output derivations to be
modified from their expected content.
This isn't the case any more.

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@ -1,32 +0,0 @@
---
synopsis: Nested debuggers are no longer supported
prs: 9920
---
Previously, evaluating an expression that throws an error in the debugger would
enter a second, nested debugger:
```
nix-repl> builtins.throw "what"
error: what
Starting REPL to allow you to inspect the current state of the evaluator.
Welcome to Nix 2.18.1. Type :? for help.
nix-repl>
```
Now, it just prints the error message like `nix repl`:
```
nix-repl> builtins.throw "what"
error:
… while calling the 'throw' builtin
at «string»:1:1:
1| builtins.throw "what"
| ^
error: what
```

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@ -1,7 +0,0 @@
---
synopsis: consistent order of lambda formals in printed expressions
prs: 9874
---
Always print lambda formals in lexicographic order rather than the internal, creation-time based symbol order.
This makes printed formals independent of the context they appear in.

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@ -1,6 +0,0 @@
---
synopsis: fix duplicate attribute error positions for `inherit`
prs: 9874
---
When an inherit caused a duplicate attribute error the position of the error was not reported correctly, placing the error with the inherit itself or at the start of the bindings block instead of the offending attribute name.

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@ -1,7 +0,0 @@
---
synopsis: "`inherit (x) ...` evaluates `x` only once"
prs: 9847
---
`inherit (x) a b ...` now evaluates the expression `x` only once for all inherited attributes rather than once for each inherited attribute.
This does not usually have a measurable impact, but side-effects (such as `builtins.trace`) would be duplicated and expensive expressions (such as derivations) could cause a measurable slowdown.

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@ -1,50 +0,0 @@
---
synopsis: Functions are printed with more detail
prs: 9606
issues: 7145
---
Functions and `builtins` are printed with more detail in `nix repl`, `nix
eval`, `builtins.trace`, and most other places values are printed.
Before:
```
$ nix repl nixpkgs
nix-repl> builtins.map
«primop»
nix-repl> builtins.map lib.id
«primop-app»
nix-repl> builtins.trace lib.id "my-value"
trace: <LAMBDA>
"my-value"
$ nix eval --file functions.nix
{ id = <LAMBDA>; primop = <PRIMOP>; primop-app = <PRIMOP-APP>; }
```
After:
```
$ nix repl nixpkgs
nix-repl> builtins.map
«primop map»
nix-repl> builtins.map lib.id
«partially applied primop map»
nix-repl> builtins.trace lib.id "my-value"
trace: «lambda id @ /nix/store/8rrzq23h2zq7sv5l2vhw44kls5w0f654-source/lib/trivial.nix:26:5»
"my-value"
$ nix eval --file functions.nix
{ id = «lambda id @ /Users/wiggles/nix/functions.nix:2:8»; primop = «primop map»; primop-app = «partially applied primop map»; }
```
This was actually released in Nix 2.20, but wasn't added to the release notes
so we're announcing it here. The historical release notes have been updated as well.
[type-error]: https://github.com/NixOS/nix/pull/9753
[coercion-error]: https://github.com/NixOS/nix/pull/9754

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@ -1,10 +0,0 @@
---
synopsis: Store paths are allowed to start with `.`
issues: 912
prs: 9867 9091 9095 9120 9121 9122 9130 9219 9224
---
Leading periods were allowed by accident in Nix 2.4. The Nix team has considered this to be a bug, but this behavior has since been relied on by users, leading to unnecessary difficulties.
From now on, leading periods are officially, definitively supported. The names `.` and `..` are disallowed, as well as those starting with `.-` or `..-`.
Nix versions that denied leading periods are documented [in the issue](https://github.com/NixOS/nix/issues/912#issuecomment-1919583286).

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@ -1,13 +0,0 @@
---
synopsis: Nix commands respect Ctrl-C
prs: 9687 6995
issues: 7245
---
Previously, many Nix commands would hang indefinitely if Ctrl-C was pressed
while performing various operations (including `nix develop`, `nix flake
update`, and so on). With several fixes to Nix's signal handlers, Nix commands
will now exit quickly after Ctrl-C is pressed.
This was actually released in Nix 2.20, but wasn't added to the release notes
so we're announcing it here. The historical release notes have been updated as well.

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@ -1,24 +0,0 @@
---
synopsis: "`nix repl` pretty-prints values"
prs: 9931
---
`nix repl` will now pretty-print values:
```
{
attrs = {
a = {
b = {
c = { };
};
};
};
list = [ 1 ];
list' = [
1
2
3
];
}
```

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@ -1,35 +0,0 @@
---
synopsis: Introduction of `--regex` and `--all` in `nix profile remove` and `nix profile upgrade`
prs: 10166
---
Previously the command-line arguments for `nix profile remove` and `nix profile upgrade` matched the package entries using regular expression.
For instance:
```
nix profile remove '.*vim.*'
```
This would remove all packages that contain `vim` in their name.
In most cases, only singular package names were used to remove and upgrade packages. Mixing this with regular expressions sometimes lead to unintended behavior. For instance, `python3.1` could match `python311`.
To avoid unintended behavior, the arguments are now only matching exact names.
Matching using regular expressions is still possible by using the new `--regex` flag:
```
nix profile remove --regex '.*vim.*'
```
One of the most useful cases for using regular expressions was to upgrade all packages. This was previously accomplished by:
```
nix profile upgrade '.*'
```
With the introduction of the `--all` flag, this now becomes more straightforward:
```
nix profile upgrade --all
```

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@ -1,37 +0,0 @@
---
synopsis: "Visual clutter in `--debugger` is reduced"
prs: 9919
---
Before:
```
info: breakpoint reached
Starting REPL to allow you to inspect the current state of the evaluator.
Welcome to Nix 2.20.0pre20231222_dirty. Type :? for help.
nix-repl> :continue
error: uh oh
Starting REPL to allow you to inspect the current state of the evaluator.
Welcome to Nix 2.20.0pre20231222_dirty. Type :? for help.
nix-repl>
```
After:
```
info: breakpoint reached
Nix 2.20.0pre20231222_dirty debugger
Type :? for help.
nix-repl> :continue
error: uh oh
nix-repl>
```

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@ -1,8 +0,0 @@
---
synopsis: "`nix repl` now respects Ctrl-C while printing values"
prs: 9927
---
`nix repl` will now halt immediately when Ctrl-C is pressed while it's printing
a value. This is useful if you got curious about what would happen if you
printed all of Nixpkgs.

View file

@ -1,22 +0,0 @@
---
synopsis: Cycle detection in `nix repl` is simpler and more reliable
prs: 9926
issues: 8672
---
The cycle detection in `nix repl`, `nix eval`, `builtins.trace`, and everywhere
else values are printed is now simpler and matches the cycle detection in
`nix-instantiate --eval` output.
Before:
```
nix eval --expr 'let self = { inherit self; }; in self'
{ self = { self = «repeated»; }; }
```
After:
```
{ self = «repeated»; }
```

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@ -1,23 +0,0 @@
---
synopsis: "In the debugger, `while evaluating the attribute` errors now include position information"
prs: 9915
---
Before:
```
0: while evaluating the attribute 'python311.pythonForBuild.pkgs'
0x600001522598
```
After:
```
0: while evaluating the attribute 'python311.pythonForBuild.pkgs'
/nix/store/hg65h51xnp74ikahns9hyf3py5mlbbqq-source/overrides/default.nix:132:27
131|
132| bootstrappingBase = pkgs.${self.python.pythonAttr}.pythonForBuild.pkgs;
| ^
133| in
```

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@ -1,9 +0,0 @@
---
synopsis: Stack size is increased on macOS
prs: 9860
---
Previously, Nix would set the stack size to 64MiB on Linux, but would leave the
stack size set to the default (approximately 8KiB) on macOS. Now, the stack
size is correctly set to 64MiB on macOS as well, which should reduce stack
overflow segfaults in deeply-recursive Nix expressions.

View file

@ -121,6 +121,7 @@
- [C++ style guide](contributing/cxx.md)
- [Release Notes](release-notes/index.md)
{{#include ./SUMMARY-rl-next.md}}
- [Release 2.21 (2024-03-11)](release-notes/rl-2.21.md)
- [Release 2.20 (2024-01-29)](release-notes/rl-2.20.md)
- [Release 2.19 (2023-11-17)](release-notes/rl-2.19.md)
- [Release 2.18 (2023-09-20)](release-notes/rl-2.18.md)

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@ -0,0 +1,366 @@
# Release 2.21.0 (2024-03-11)
- CLI options `--arg-from-file` and `--arg-from-stdin` [#10122](https://github.com/NixOS/nix/pull/10122)
The new CLI option `--arg-from-file` *name* *path* passes the contents
of file *path* as a string value via the function argument *name* to a
Nix expression. Similarly, the new option `--arg-from-stdin` *name*
reads the contents of the string from standard input.
- Concise error printing in `nix repl` [#9928](https://github.com/NixOS/nix/pull/9928)
Previously, if an element of a list or attribute set threw an error while
evaluating, `nix repl` would print the entire error (including source location
information) inline. This output was clumsy and difficult to parse:
```
nix-repl> { err = builtins.throw "uh oh!"; }
{ err = «error:
… while calling the 'throw' builtin
at «string»:1:9:
1| { err = builtins.throw "uh oh!"; }
| ^
error: uh oh!»; }
```
Now, only the error message is displayed, making the output much more readable.
```
nix-repl> { err = builtins.throw "uh oh!"; }
{ err = «error: uh oh!»; }
```
However, if the whole expression being evaluated throws an error, source
locations and (if applicable) a stack trace are printed, just like you'd expect:
```
nix-repl> builtins.throw "uh oh!"
error:
… while calling the 'throw' builtin
at «string»:1:1:
1| builtins.throw "uh oh!"
| ^
error: uh oh!
```
- `--debugger` can now access bindings from `let` expressions [#8827](https://github.com/NixOS/nix/issues/8827) [#9918](https://github.com/NixOS/nix/pull/9918)
Breakpoints and errors in the bindings of a `let` expression can now access
those bindings in the debugger. Previously, only the body of `let` expressions
could access those bindings.
- Enter the `--debugger` when `builtins.trace` is called if `debugger-on-trace` is set [#9914](https://github.com/NixOS/nix/pull/9914)
If the `debugger-on-trace` option is set and `--debugger` is given,
`builtins.trace` calls will behave similarly to `builtins.break` and will enter
the debug REPL. This is useful for determining where warnings are being emitted
from.
- Debugger prints source position information [#9913](https://github.com/NixOS/nix/pull/9913)
The `--debugger` now prints source location information, instead of the
pointers of source location information. Before:
```
nix-repl> :bt
0: while evaluating the attribute 'python311.pythonForBuild.pkgs'
0x600001522598
```
After:
```
0: while evaluating the attribute 'python311.pythonForBuild.pkgs'
/nix/store/hg65h51xnp74ikahns9hyf3py5mlbbqq-source/overrides/default.nix:132:27
131|
132| bootstrappingBase = pkgs.${self.python.pythonAttr}.pythonForBuild.pkgs;
| ^
133| in
```
- The `--debugger` will start more reliably in `let` expressions and function calls [#6649](https://github.com/NixOS/nix/issues/6649) [#9917](https://github.com/NixOS/nix/pull/9917)
Previously, if you attempted to evaluate this file with the debugger:
```nix
let
a = builtins.trace "before inner break" (
builtins.break "hello"
);
b = builtins.trace "before outer break" (
builtins.break a
);
in
b
```
Nix would correctly enter the debugger at `builtins.break a`, but if you asked
it to `:continue`, it would skip over the `builtins.break "hello"` expression
entirely.
Now, Nix will correctly enter the debugger at both breakpoints.
- Fix a FOD sandbox escape
Cooperating Nix derivations could send file descriptors to files in the Nix
store to each other via Unix domain sockets in the abstract namespace. This
allowed one derivation to modify the output of the other derivation, after Nix
has registered the path as "valid" and immutable in the Nix database.
In particular, this allowed the output of fixed-output derivations to be
modified from their expected content.
This isn't the case any more.
- Nested debuggers are no longer supported [#9920](https://github.com/NixOS/nix/pull/9920)
Previously, evaluating an expression that throws an error in the debugger would
enter a second, nested debugger:
```
nix-repl> builtins.throw "what"
error: what
Starting REPL to allow you to inspect the current state of the evaluator.
Welcome to Nix 2.18.1. Type :? for help.
nix-repl>
```
Now, it just prints the error message like `nix repl`:
```
nix-repl> builtins.throw "what"
error:
… while calling the 'throw' builtin
at «string»:1:1:
1| builtins.throw "what"
| ^
error: what
```
- consistent order of lambda formals in printed expressions [#9874](https://github.com/NixOS/nix/pull/9874)
Always print lambda formals in lexicographic order rather than the internal, creation-time based symbol order.
This makes printed formals independent of the context they appear in.
- fix duplicate attribute error positions for `inherit` [#9874](https://github.com/NixOS/nix/pull/9874)
When an inherit caused a duplicate attribute error the position of the error was not reported correctly, placing the error with the inherit itself or at the start of the bindings block instead of the offending attribute name.
- `inherit (x) ...` evaluates `x` only once [#9847](https://github.com/NixOS/nix/pull/9847)
`inherit (x) a b ...` now evaluates the expression `x` only once for all inherited attributes rather than once for each inherited attribute.
This does not usually have a measurable impact, but side-effects (such as `builtins.trace`) would be duplicated and expensive expressions (such as derivations) could cause a measurable slowdown.
- Functions are printed with more detail [#7145](https://github.com/NixOS/nix/issues/7145) [#9606](https://github.com/NixOS/nix/pull/9606)
Functions and `builtins` are printed with more detail in `nix repl`, `nix
eval`, `builtins.trace`, and most other places values are printed.
Before:
```
$ nix repl nixpkgs
nix-repl> builtins.map
«primop»
nix-repl> builtins.map lib.id
«primop-app»
nix-repl> builtins.trace lib.id "my-value"
trace: <LAMBDA>
"my-value"
$ nix eval --file functions.nix
{ id = <LAMBDA>; primop = <PRIMOP>; primop-app = <PRIMOP-APP>; }
```
After:
```
$ nix repl nixpkgs
nix-repl> builtins.map
«primop map»
nix-repl> builtins.map lib.id
«partially applied primop map»
nix-repl> builtins.trace lib.id "my-value"
trace: «lambda id @ /nix/store/8rrzq23h2zq7sv5l2vhw44kls5w0f654-source/lib/trivial.nix:26:5»
"my-value"
$ nix eval --file functions.nix
{ id = «lambda id @ /Users/wiggles/nix/functions.nix:2:8»; primop = «primop map»; primop-app = «partially applied primop map»; }
```
This was actually released in Nix 2.20, but wasn't added to the release notes
so we're announcing it here. The historical release notes have been updated as well.
[type-error]: https://github.com/NixOS/nix/pull/9753
[coercion-error]: https://github.com/NixOS/nix/pull/9754
- Store paths are allowed to start with `.` [#912](https://github.com/NixOS/nix/issues/912) [#9091](https://github.com/NixOS/nix/pull/9091) [#9095](https://github.com/NixOS/nix/pull/9095) [#9120](https://github.com/NixOS/nix/pull/9120) [#9121](https://github.com/NixOS/nix/pull/9121) [#9122](https://github.com/NixOS/nix/pull/9122) [#9130](https://github.com/NixOS/nix/pull/9130) [#9219](https://github.com/NixOS/nix/pull/9219) [#9224](https://github.com/NixOS/nix/pull/9224) [#9867](https://github.com/NixOS/nix/pull/9867)
Leading periods were allowed by accident in Nix 2.4. The Nix team has considered this to be a bug, but this behavior has since been relied on by users, leading to unnecessary difficulties.
From now on, leading periods are officially, definitively supported. The names `.` and `..` are disallowed, as well as those starting with `.-` or `..-`.
Nix versions that denied leading periods are documented [in the issue](https://github.com/NixOS/nix/issues/912#issuecomment-1919583286).
- Nix commands respect Ctrl-C [#7245](https://github.com/NixOS/nix/issues/7245) [#6995](https://github.com/NixOS/nix/pull/6995) [#9687](https://github.com/NixOS/nix/pull/9687)
Previously, many Nix commands would hang indefinitely if Ctrl-C was pressed
while performing various operations (including `nix develop`, `nix flake
update`, and so on). With several fixes to Nix's signal handlers, Nix commands
will now exit quickly after Ctrl-C is pressed.
This was actually released in Nix 2.20, but wasn't added to the release notes
so we're announcing it here. The historical release notes have been updated as well.
- `nix repl` pretty-prints values [#9931](https://github.com/NixOS/nix/pull/9931)
`nix repl` will now pretty-print values:
```
{
attrs = {
a = {
b = {
c = { };
};
};
};
list = [ 1 ];
list' = [
1
2
3
];
}
```
- Introduction of `--regex` and `--all` in `nix profile remove` and `nix profile upgrade` [#10166](https://github.com/NixOS/nix/pull/10166)
Previously the command-line arguments for `nix profile remove` and `nix profile upgrade` matched the package entries using regular expression.
For instance:
```
nix profile remove '.*vim.*'
```
This would remove all packages that contain `vim` in their name.
In most cases, only singular package names were used to remove and upgrade packages. Mixing this with regular expressions sometimes lead to unintended behavior. For instance, `python3.1` could match `python311`.
To avoid unintended behavior, the arguments are now only matching exact names.
Matching using regular expressions is still possible by using the new `--regex` flag:
```
nix profile remove --regex '.*vim.*'
```
One of the most useful cases for using regular expressions was to upgrade all packages. This was previously accomplished by:
```
nix profile upgrade '.*'
```
With the introduction of the `--all` flag, this now becomes more straightforward:
```
nix profile upgrade --all
```
- Visual clutter in `--debugger` is reduced [#9919](https://github.com/NixOS/nix/pull/9919)
Before:
```
info: breakpoint reached
Starting REPL to allow you to inspect the current state of the evaluator.
Welcome to Nix 2.20.0pre20231222_dirty. Type :? for help.
nix-repl> :continue
error: uh oh
Starting REPL to allow you to inspect the current state of the evaluator.
Welcome to Nix 2.20.0pre20231222_dirty. Type :? for help.
nix-repl>
```
After:
```
info: breakpoint reached
Nix 2.20.0pre20231222_dirty debugger
Type :? for help.
nix-repl> :continue
error: uh oh
nix-repl>
```
- `nix repl` now respects Ctrl-C while printing values [#9927](https://github.com/NixOS/nix/pull/9927)
`nix repl` will now halt immediately when Ctrl-C is pressed while it's printing
a value. This is useful if you got curious about what would happen if you
printed all of Nixpkgs.
- Cycle detection in `nix repl` is simpler and more reliable [#8672](https://github.com/NixOS/nix/issues/8672) [#9926](https://github.com/NixOS/nix/pull/9926)
The cycle detection in `nix repl`, `nix eval`, `builtins.trace`, and everywhere
else values are printed is now simpler and matches the cycle detection in
`nix-instantiate --eval` output.
Before:
```
nix eval --expr 'let self = { inherit self; }; in self'
{ self = { self = «repeated»; }; }
```
After:
```
{ self = «repeated»; }
```
- In the debugger, `while evaluating the attribute` errors now include position information [#9915](https://github.com/NixOS/nix/pull/9915)
Before:
```
0: while evaluating the attribute 'python311.pythonForBuild.pkgs'
0x600001522598
```
After:
```
0: while evaluating the attribute 'python311.pythonForBuild.pkgs'
/nix/store/hg65h51xnp74ikahns9hyf3py5mlbbqq-source/overrides/default.nix:132:27
131|
132| bootstrappingBase = pkgs.${self.python.pythonAttr}.pythonForBuild.pkgs;
| ^
133| in
```
- Stack size is increased on macOS [#9860](https://github.com/NixOS/nix/pull/9860)
Previously, Nix would set the stack size to 64MiB on Linux, but would leave the
stack size set to the default (approximately 8KiB) on macOS. Now, the stack
size is correctly set to 64MiB on macOS as well, which should reduce stack
overflow segfaults in deeply-recursive Nix expressions.