Clarify the description of StorePath construction

This commit is contained in:
Carlo Nucera 2020-06-03 16:08:32 -04:00
parent 01572c2198
commit 132d6f2c24

View file

@ -69,7 +69,7 @@ string storePathToHash(const Path & path)
/* Store paths have the following form: /* Store paths have the following form:
<store>/<h>-<name> <realized-path> = <store>/<h>-<name>
where where
@ -93,11 +93,14 @@ string storePathToHash(const Path & path)
<type> = one of: <type> = one of:
"text:<r1>:<r2>:...<rN>" "text:<r1>:<r2>:...<rN>"
for plain text files written to the store using for plain text files written to the store using
addTextToStore(); <r1> ... <rN> are the references of the addTextToStore(); <r1> ... <rN> are the store paths referenced
path. by this path, in the form described by <realized-path>
"source" "source:<r1>:<r2>:...:<rN>:self"
for paths copied to the store using addToStore() when recursive for paths copied to the store using addToStore() when recursive
= true and hashAlgo = "sha256" = true and hashAlgo = "sha256". Just like in the text case, we
can have the store paths referenced by the path.
Additionally, we can have an optional :self label to denote self
reference.
"output:<id>" "output:<id>"
for either the outputs created by derivations, OR paths copied for either the outputs created by derivations, OR paths copied
to the store using addToStore() with recursive != true or to the store using addToStore() with recursive != true or
@ -125,6 +128,12 @@ string storePathToHash(const Path & path)
the contents of the path (or expected contents of the the contents of the path (or expected contents of the
path for fixed-output derivations) path for fixed-output derivations)
Note that since an output derivation has always type output, while
something added by addToStore can have type output or source depending
on the hash, this means that the same input can be hashed differently
if added to the store via addToStore or via a derivation, in the sha256
recursive case.
It would have been nicer to handle fixed-output derivations under It would have been nicer to handle fixed-output derivations under
"source", e.g. have something like "source:<rec><algo>", but we're "source", e.g. have something like "source:<rec><algo>", but we're
stuck with this for now... stuck with this for now...