{
"$schema":"http://json-schema.org/draft-07/schema#",
"title":"Spack concretizer configuration file schema",
"type":"object",
"additionalProperties":false,
"properties":{
"concretizer":{
"type":"object",
"additionalProperties":false,
"description":"Concretizer configuration that controls dependency selection, package reuse, and solver behavior",
"properties":{
"force":{
"type":"boolean",
"default":false,
"description":"Force re-concretization when concretizing environments"
},
"reuse":{
"description":"Controls how aggressively Spack reuses installed packages and build caches during concretization",
"oneOf":[
{
"type":"boolean",
"description":"If true, reuse installed packages and build caches for all specs; if false, always perform fresh concretization"
},
{
"type":"string",
"enum":[
"dependencies"
],
"description":"Reuse installed packages and build caches only for dependencies, not root specs"
},
{
"type":"object",
"description":"Advanced reuse configuration with fine-grained control over which specs are reused",
"properties":{
"roots":{
"type":"boolean",
"description":"If true, root specs are reused; if false, only dependencies of root specs are reused"
},
"include":{
"type":"array",
"items":{
"type":"string"
},
"description":"List of spec constraints. Reusable specs must match at least one constraint"
},
"exclude":{
"type":"array",
"items":{
"type":"string"
},
"description":"List of spec constraints. Reusable specs must not match any constraint"
},
"from":{
"type":"array",
"description":"List of sources from which reused specs are taken",
"items":{
"type":"object",
"description":"Source configuration for reusable specs",
"properties":{
"type":{
"type":"string",
"enum":[
"local",
"buildcache",
"external",
"environment"
],
"description":"Type of source: 'local' (installed packages), 'buildcache' (remote binaries), 'external' (system packages), or 'environment' (from specific environment)"
},
"path":{
"type":"string",
"description":"Path to the source (for environment type sources)"
},
"include":{
"type":"array",
"items":{
"type":"string"
},
"description":"Spec constraints that must be matched for this source (overrides global include)"
},
"exclude":{
"type":"array",
"items":{
"type":"string"
},
"description":"Spec constraints that must not be matched for this source (overrides global exclude)"
}
}
}
}
}
}
]
},
"enable_node_namespace":{
"type":"boolean",
"description":"Enable node namespace functionality in the concretizer"
},
"targets":{
"type":"object",
"description":"Controls which target microarchitectures are considered during concretization",
"properties":{
"host_compatible":{
"type":"boolean",
"description":"If true, only allow targets compatible with the current host; if false, allow any target (e.g., concretize for icelake while running on haswell)"
},
"granularity":{
"type":"string",
"enum":[
"generic",
"microarchitectures"
],
"description":"Target selection granularity: 'microarchitectures' (e.g., haswell, skylake) or 'generic' (e.g., x86_64_v3, aarch64)"
}
}
},
"unify":{
"description":"Controls whether environment specs are concretized together or separately",
"oneOf":[
{
"type":"boolean",
"description":"If true, concretize environment root specs together for unified dependencies; if false, concretize each spec independently"
},
{
"type":"string",
"enum":[
"when_possible"
],
"description":"Maximizes reuse, while allowing multiple instances of the same package"
}
]
},
"compiler_mixing":{
"oneOf":[
{
"type":"boolean"
},
{
"type":"array"
}
],
"description":"Whether to allow compiler mixing between link/run dependencies"
},
"splice":{
"type":"object",
"additionalProperties":false,
"description":"Configuration for spec splicing: replacing dependencies with ABI-compatible alternatives to improve package reuse",
"properties":{
"explicit":{
"type":"array",
"default":[],
"description":"List of explicit splice configurations to replace specific dependencies",
"items":{
"type":"object",
"required":[
"target",
"replacement"
],
"additionalProperties":false,
"description":"Explicit splice configuration",
"properties":{
"target":{
"type":"string",
"description":"Abstract spec to be replaced (e.g., 'mpi' or specific package)"
},
"replacement":{
"type":"string",
"description":"Concrete spec with hash to use as replacement (e.g., 'mpich/abcdef')"
},
"transitive":{
"type":"boolean",
"default":false,
"description":"If true, use transitive splice (conflicts resolved using replacement dependencies); if false, use intransitive splice (conflicts resolved using original dependencies)"
}
}
}
},
"automatic":{
"type":"boolean",
"description":"Enable automatic splicing for ABI-compatible packages (experimental feature)"
}
}
},
"duplicates":{
"type":"object",
"description":"Controls whether the dependency graph can contain multiple configurations of the same package",
"properties":{
"strategy":{
"type":"string",
"enum":[
"none",
"minimal",
"full"
],
"description":"Duplication strategy: 'none' (single config per package), 'minimal' (allow build-tools duplicates), 'full' (experimental: allow full build-tool stack separation)"
},
"max_dupes":{
"type":"object",
"description":"Maximum number of duplicates allowed per package when using strategies that permit duplicates",
"additionalProperties":{
"type":"integer",
"minimum":1,
"description":"Maximum number of duplicate instances for this package"
}
}
}
},
"static_analysis":{
"type":"boolean",
"description":"Enable static analysis to reduce concretization time by generating smaller ASP problems"
},
"timeout":{
"type":"integer",
"minimum":0,
"description":"Maximum time in seconds for the solve phase (0 means no time limit)"
},
"error_on_timeout":{
"type":"boolean",
"description":"If true, timeout always results in error; if false, use best suboptimal solution found before timeout (yields unreproducible results)"
},
"os_compatible":{
"type":"object",
"additionalProperties":{
"type":"array"
},
"description":"Compatibility mapping between operating systems for reuse of compilers and packages (key: target OS, value: list of compatible source OSes)"
},
"concretization_cache":{
"type":"object",
"description":"Configuration for caching solver outputs from successful concretization runs",
"properties":{
"enable":{
"type":"boolean",
"description":"Whether to utilize a cache of solver outputs from successful concretization runs"
},
"url":{
"type":"string",
"description":"Path to the location where Spack will root the concretization cache"
},
"entry_limit":{
"type":"integer",
"minimum":0,
"description":"Limit on the number of concretization results that Spack will cache (0 disables pruning)"
}
}
},
"externals":{
"type":"object",
"description":"Configuration for how Spack handles external packages during concretization",
"properties":{
"completion":{
"type":"string",
"enum":[
"architecture_only",
"default_variants"
],
"description":"Controls how missing information (variants, etc.) is completed for external packages: 'architecture_only' completes only mandatory architectural information; 'default_variants' also completes missing variants using their default values"
}
}
}
}
}
}
}