d6a88ed74d
Introduces the `id` field to `build.zig.zon`. Together with name, this represents a globally unique package identifier. This field should be initialized with a 16-bit random number when the package is first created, and then *never change*. This allows Zig to unambiguously detect when one package is an updated version of another. When forking a Zig project, this id should be regenerated with a new random number if the upstream project is still maintained. Otherwise, the fork is *hostile*, attempting to take control over the original project's identity. `0x0000` is invalid because it obviously means a random number wasn't used. `0xffff` is reserved to represent "naked" packages. Tracking issue #14288 Additionally: * Fix bad path in error messages regarding build.zig.zon file. * Manifest validates that `name` and `version` field of build.zig.zon are maximum 32 bytes. * Introduce error for root package to not switch to enum literal for name. * Introduce error for root package to omit `id`. * Update init template to generate `id` * Update init template to populate `minimum_zig_version`. * New package hash format changes: - name and version limited to 32 bytes via error rather than truncation - truncate sha256 to 192 bits rather than 40 bits - include the package id This means that, given only the package hashes for a complete dependency tree, it is possible to perform version selection and know the final size on disk, without doing any fetching whatsoever. This prevents wasted bandwidth since package versions not selected do not need to be fetched.
3.1 KiB
build.zig.zon Documentation
This is the manifest file for build.zig scripts. It is named build.zig.zon in order to make it clear that it is metadata specifically pertaining to build.zig.
- build root - the directory that contains
build.zig
Top-Level Fields
name
Enum literal. Required.
This is the default name used by packages depending on this one. For example,
when a user runs zig fetch --save <url>, this field is used as the key in the
dependencies table. Although the user can choose a different name, most users
will stick with this provided value.
It is redundant to include "zig" in this name because it is already within the Zig package namespace.
Must be a valid bare Zig identifier (don't @ me), limited to 32 bytes.
id
Together with name, this represents a globally unique package identifier. This field should be initialized with a 16-bit random number when the package is first created, and then never change. This allows Zig to unambiguously detect when one package is an updated version of another.
When forking a Zig project, this id should be regenerated with a new random number if the upstream project is still maintained. Otherwise, the fork is hostile, attempting to take control over the original project's identity.
0x0000 is invalid because it obviously means a random number wasn't used.
0xffff is reserved to represent "naked" packages.
version
String. Required.
Limited to 32 bytes.
minimum_zig_version
String. Optional.
This is currently advisory only; the compiler does not yet do anything with this version.
dependencies
Struct.
Each dependency must either provide a url and hash, or a path.
url
String.
When updating this field to a new URL, be sure to delete the corresponding
hash, otherwise you are communicating that you expect to find the old hash at
the new URL. If the contents of a URL change this will result in a hash mismatch
which will prevent zig from using it.
hash
String.
This is computed from the file contents of the directory of files that is
obtained after fetching url and applying the inclusion rules given by
paths.
This field is the source of truth; packages do not come from a url; they
come from a hash. url is just one of many possible mirrors for how to
obtain a package matching this hash.
path
String.
When this is provided, the package is found in a directory relative to the
build root. In this case the package's hash is irrelevant and therefore not
computed. This field and url are mutually exclusive.
lazy
Boolean.
When this is set to true, a package is declared to be lazily fetched. This
makes the dependency only get fetched if it is actually used.
paths
List. Required.
Specifies the set of files and directories that are included in this package.
Paths are relative to the build root. Use the empty string ("") to refer to
the build root itself.
Only files included in the package are used to compute a package's hash.