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C API: Clarify valid use of bindings ordering

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Robert Hensing 2025-09-20 00:47:00 +02:00
parent d0b1caf53a
commit c121c65640
1 changed files with 37 additions and 5 deletions
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42
src/libexpr-c/nix_api_value.h
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@ -315,10 +315,20 @@ nix_get_attr_byname_lazy(nix_c_context * context, const nix_value * value, EvalS
*/
bool nix_has_attr_byname(nix_c_context * context, const nix_value * value, EvalState * state, const char * name);
/** @brief Get an attribute by index in the sorted bindings
/** @brief Get an attribute by index
*
* Also gives you the name.
*
* Attributes are returned in an unspecified order which is NOT suitable for
* reproducible operations. In Nix's domain, reproducibility is paramount. The caller
* is responsible for sorting the attributes or storing them in an ordered map to
* ensure deterministic behavior in your application.
*
* @note When Nix does sort attributes, which it does for virtually all intermediate
* operations and outputs, it uses byte-wise lexicographic order (equivalent to
* lexicographic order by Unicode scalar value for valid UTF-8). We recommend
* applying this same ordering for consistency.
*
* Use nix_gc_decref when you're done with the pointer
* @param[out] context Optional, stores error information
* @param[in] value Nix value to inspect
@ -330,10 +340,22 @@ bool nix_has_attr_byname(nix_c_context * context, const nix_value * value, EvalS
nix_value *
nix_get_attr_byidx(nix_c_context * context, nix_value * value, EvalState * state, unsigned int i, const char ** name);
/** @brief Get an attribute by index in the sorted bindings, without forcing evaluation of the attribute's value
/** @brief Get an attribute by index, without forcing evaluation of the attribute's value
*
* Also gives you the name. Returns the attribute value without forcing its evaluation, allowing access to lazy values.
* The attribute set value itself must already be evaluated.
* Also gives you the name.
*
* Returns the attribute value without forcing its evaluation, allowing access to lazy values.
* The attribute set value itself must already have been evaluated.
*
* Attributes are returned in an unspecified order which is NOT suitable for
* reproducible operations. In Nix's domain, reproducibility is paramount. The caller
* is responsible for sorting the attributes or storing them in an ordered map to
* ensure deterministic behavior in your application.
*
* @note When Nix does sort attributes, which it does for virtually all intermediate
* operations and outputs, it uses byte-wise lexicographic order (equivalent to
* lexicographic order by Unicode scalar value for valid UTF-8). We recommend
* applying this same ordering for consistency.
*
* Use nix_gc_decref when you're done with the pointer
* @param[out] context Optional, stores error information
@ -346,10 +368,20 @@ nix_get_attr_byidx(nix_c_context * context, nix_value * value, EvalState * state
nix_value * nix_get_attr_byidx_lazy(
nix_c_context * context, nix_value * value, EvalState * state, unsigned int i, const char ** name);
/** @brief Get an attribute name by index in the sorted bindings
/** @brief Get an attribute name by index
*
* Returns the attribute name without forcing evaluation of the attribute's value.
*
* Attributes are returned in an unspecified order which is NOT suitable for
* reproducible operations. In Nix's domain, reproducibility is paramount. The caller
* is responsible for sorting the attributes or storing them in an ordered map to
* ensure deterministic behavior in your application.
*
* @note When Nix does sort attributes, which it does for virtually all intermediate
* operations and outputs, it uses byte-wise lexicographic order (equivalent to
* lexicographic order by Unicode scalar value for valid UTF-8). We recommend
* applying this same ordering for consistency.
*
* Owned by the nix EvalState
* @param[out] context Optional, stores error information
* @param[in] value Nix value to inspect