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Maximilian Bosch 7c76964daa
libexpr: misc improvements for proper error position
When working on some more complex Nix code, there are sometimes rather
unhelpful or misleading error messages, especially if coerce-errors are
thrown.

This patch is a first steps towards improving that. I'm happy to file
more changes after that, but I'd like to gather some feedback first.

To summarize, this patch does the following things:

* Attrsets (a.k.a. `Bindings` in `libexpr`) now have a `Pos`. This is
  helpful e.g. to identify which attribute-set in `listToAttrs` is
  invalid.

* The `Value`-struct has a new method named `determinePos` which tries
  to guess the position of a value and falls back to a default if that's
  not possible.

  This can be used to provide better messages if a coercion fails.

* The new `determinePos`-API is used by `builtins.concatMap` now. With
  that change, Nix shows the exact position in the error where a wrong
  value was returned by the lambda.

  To make sure it's still obvious that `concatMap` is the problem,
  another stack-frame was added.

* The changes described above can be added to every other `primop`, but
  first I'd like to get some feedback about the overall approach.
2021-04-13 23:12:38 +02:00
.github Bump cachix/cachix-action from v9 to v10 2021-04-12 05:21:11 +00:00
config Update config.guess for proper arm64 macOS detection 2020-12-02 19:14:34 -06:00
contrib function-trace: always show the trace 2019-09-18 23:23:21 +02:00
doc/manual [prerequisites]: add JSON lib dependency 2021-04-01 22:54:09 +01:00
m4 autoconf: Fix C++17 detection not working on Ubuntu 16.04. 2019-07-03 04:32:25 +02:00
maintainers set Content-Type to "text/plain" for install script 2020-08-20 13:21:22 +02:00
misc Add some missing clean-files 2020-10-18 20:32:59 +02:00
mk Merge pull request #4582 from puckipedia/cppflags 2021-03-01 13:08:14 +01:00
nix-rust Remove 'dist' target 2020-12-03 16:17:58 +01:00
perl Make sodium a required dependency 2021-01-06 17:56:53 +01:00
scripts Merge pull request #4532 from abathur/macos_nixbld_ids 2021-03-25 10:35:56 +01:00
src libexpr: misc improvements for proper error position 2021-04-13 23:12:38 +02:00
tests Merge pull request #4676 from bjornfor/fix-fetchgit-ref-head 2021-03-30 12:07:05 +02:00
.dir-locals.el .dir-locals.el: Set c-block-comment-prefix 2020-07-10 11:21:06 +02:00
.editorconfig Add .editorconfig 2017-06-05 22:57:28 +01:00
.gitignore Generate separate manpages for each nix subcommand 2020-12-02 23:23:23 +01:00
.version Revert "Bump version to 3.0" 2020-10-26 11:30:18 +01:00
bootstrap.sh bootstrap: Simplify & make more robust. 2011-09-06 12:11:05 +00:00
configure.ac Add x86_64 compute levels as additional system types 2021-02-22 09:11:15 +01:00
COPYING * Change this to LGPL to keep the government happy. 2006-04-25 16:41:06 +00:00
default.nix Simplify shell.nix and default.nix 2020-06-17 19:21:46 +02:00
flake.lock flake.lock: Update 2021-02-26 16:03:39 +01:00
flake.nix Merge pull request #4239 from tweag/test-against-old-daemon 2021-03-29 16:15:36 +02:00
local.mk Remove 'dist' target 2020-12-03 16:17:58 +01:00
Makefile Move command plugin interface to libnixcmd 2021-01-26 06:22:24 -05:00
Makefile.config.in Properly propagate libseccomp linker flags 2021-02-26 23:01:16 +00:00
precompiled-headers.h Config: Use nlohmann/json 2020-08-20 11:02:16 +02:00
README.md README: fix link to hacking guide 2020-12-28 09:30:14 -08:00
shell.nix Add back flake-compat shell.nix 2020-07-17 14:58:59 +00:00

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