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pre -> fingerprint in store path grammar

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As suggested by @roberth in
https://github.com/NixOS/nix/pull/9295#discussion_r1486402040.

Thanks!
This commit is contained in:
John Ericson 2024-02-12 11:22:08 -05:00
parent 95190e68ed
commit 30f6b0f9c5
1 changed files with 5 additions and 5 deletions
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10
doc/manual/src/protocols/store-path.md
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@ -12,11 +12,11 @@ store-path = store-dir "/" digest "-" name
``` ```
where where
- `digest` = base-32 representation of the first 160 bits of a [SHA-256] hash of `pre` - `digest` = base-32 representation of the first 160 bits of a [SHA-256] hash of `fingerprint`
Th is :the hash part of the store name Th is :the hash part of the store name
- `pre` = the string - `fingerprint` = the string
```ebnf ```ebnf
type ":" sha256 ":" inner-digest ":" store ":" name type ":" sha256 ":" inner-digest ":" store ":" name
@ -57,9 +57,9 @@ where
`id` is the name of the output (usually, "out"). `id` is the name of the output (usually, "out").
For content-addressed store objects, `id`, is always "out". For content-addressed store objects, `id`, is always "out".
- `inner-digest` = base-16 representation of a SHA-256 hash of `inner-pre` - `inner-digest` = base-16 representation of a SHA-256 hash of `inner-fingerprint`
- `inner-pre` = one of the following based on `type`: - `inner-fingerprint` = one of the following based on `type`:
- if `type` = `"text:" ...`: - if `type` = `"text:" ...`:
@ -108,7 +108,7 @@ in that both can represent data hashed by its SHA-256 NAR serialization.
The original reason for this way of computing names was to prevent name collisions (for security). The original reason for this way of computing names was to prevent name collisions (for security).
For instance, the thinking was that it shouldn't be feasible to come up with a derivation whose output path collides with the path for a copied source. For instance, the thinking was that it shouldn't be feasible to come up with a derivation whose output path collides with the path for a copied source.
The former would have an `inner-pre` starting with `output:out:`, while the latter would have an `inner-pre` starting with `source:`. The former would have an `inner-fingerprint` starting with `output:out:`, while the latter would have an `inner-fingerprint` starting with `source:`.
Since `64519cfd657d024ae6e2bb74cb21ad21b886fd2a` (2008), however, it was decided that separting derivation-produced vs manually-hashed content-addressed data like this was not useful. Since `64519cfd657d024ae6e2bb74cb21ad21b886fd2a` (2008), however, it was decided that separting derivation-produced vs manually-hashed content-addressed data like this was not useful.
Now, data this is to be SHA-256 + NAR-serialization content-addressed always uses the `source:...` construction, regardless of how it was produced (manually or by derivation). Now, data this is to be SHA-256 + NAR-serialization content-addressed always uses the `source:...` construction, regardless of how it was produced (manually or by derivation).