wroclaw-git-backups/nix
1
0
Fork 0
mirror of https://github.com/NixOS/nix synced 2025-06-27 12:41:15 +02:00
Code Activity

Fix derivation load assertion errors

Browse source 
When loading a derivation from a JSON, malformed input would trigger
cryptic "assertion failed" errors. Simply replacing calls to `operator []`
with calls to `.at()` was not enough, as this would cause json.execptions
to be printed verbatim.

Display nice error messages instead and give some indication where the
error happened.

*Before:*

```
$ echo 4 | nix derivation add
error: [json.exception.type_error.305] cannot use operator[] with a string argument with number

$ nix derivation show nixpkgs#hello | nix derivation add
Assertion failed: (it != m_value.object->end()), function operator[], file /nix/store/8h9pxgq1776ns6qi5arx08ifgnhmgl22-nlohmann_json-3.11.2/include/nlohmann/json.hpp, line 2135.

$ nix derivation show nixpkgs#hello | jq '.[] | .name = 5' | nix derivation add
error: [json.exception.type_error.302] type must be string, but is object

$ nix derivation show nixpkgs#hello | jq '.[] | .outputs = { out: "/nix/store/8j3f8j-hello" }' | nix derivation add
error: [json.exception.type_error.302] type must be object, but is string

```

*After:*

```
$ echo 4 | nix derivation add
error: Expected JSON of derivation to be of type 'object', but it is of type 'number'

$ nix derivation show nixpkgs#hello | nix derivation add
error: Expected JSON object to contain key 'name' but it doesn't

$ nix derivation show nixpkgs#hello | jq '.[] | .name = 5' | nix derivation add
error: Expected JSON value to be of type 'string' but it is of type 'number'

$ nix derivation show nixpkgs#hello | jq '.[] | .outputs = { out: "/nix/store/8j3f8j-hello" }' | nix derivation add
error:
       … while reading key 'outputs'

       error: Expected JSON value to be of type 'object' but it is of type 'string'
```
This commit is contained in:
Felix Uhl 2023-07-28 22:23:56 +02:00
parent dcdd5fed74
commit 3fefc2b284
4 changed files with 76 additions and 12 deletions
Download patch file Download diff file Expand all files Collapse all files

24
src/libutil/json-utils.cc
View file

@ -1,4 +1,5 @@
#include "json-utils.hh"
#include "error.hh"
namespace nix {
@ -16,4 +17,27 @@ nlohmann::json * get(nlohmann::json & map, const std::string & key)
return &*i;
}
const nlohmann::json & valueAt(
const nlohmann::json & map,
const std::string & key)
{
if (!map.contains(key))
throw Error("Expected JSON object to contain key '%s' but it doesn't", key);
return map[key];
}
const nlohmann::json & ensureType(
const nlohmann::json & value,
nlohmann::json::value_type expectedType
)
{
if (value.type() != expectedType)
throw Error(
"Expected JSON value to be of type '%s' but it is of type '%s'",
nlohmann::json(expectedType).type_name(),
value.type_name());
return value;
}
}