product:configure

Interactive SPL feature configurator with constraint propagation and formal validation.

Usage
Description
1. What it does
Constraint propagation
1. Visual feedback
Example output
Version resolution
Validation
Requirements
UVL alignment
See also

Usage

splent product:configure

No options – the command is fully interactive.

Description

product:configure reads the UVL model from the SPL catalog, walks the entire feature tree interactively, and writes the resulting feature selection to the product’s pyproject.toml.

The configurator respects all UVL group semantics:

Group type	Semantics	Prompt style
mandatory	Always selected	Auto-selected, no prompt
optional	User’s choice	Yes/no confirmation
alternative	Exactly one from N	Numbered list, pick one
or	One or more from N	Yes/no per child, minimum enforced
cardinality	[n..m] from N	Yes/no per child, min/max enforced

What it does

Loads the UVL model via Flamapy from splent_catalog/<spl_name>/<spl_name>.uvl
Computes mandatory features from the root down
Walks the feature tree recursively, prompting for selections per group type
Propagates constraints in real-time (implications, exclusions, parent-chain activation)
Shows auto-selected and blocked features as propagation resolves them
Validates the final configuration against the UVL model (SAT check via Flamapy)
Clears existing feature entries and symlinks
Resolves versions from cache or PyPI
Writes the new feature list to [tool.splent.features] in pyproject.toml

Constraint propagation

The configurator propagates constraints after every user selection:

Rule	Direction	Example
A selected and A => B	Forward	Selecting `confirmemail` auto-selects `auth`
Child selected => parent selected	Forward	Selecting a leaf activates its ancestor chain
Parent selected => mandatory children	Forward	Selecting a group parent adds mandatory children
A selected and A excludes B	Exclusion	Selecting `filesystem_session` blocks `redis_session`
B excluded and A => B	Contrapositive	If `auth` is blocked, anything that requires `auth` is also blocked

The propagation runs in a fixed-point loop until no more changes occur.

Visual feedback

During configuration, the command shows real-time feedback:

    Optional features:

    Include admin? (requires: + auth)  [y/N]: y
      ↳ auth  (auto-selected)

    Include session_filesystem?  [y/N]: n
    Include session_redis?  [y/N]: y
      ↳ redis  (auto-selected)

Blocked features are shown in red and cannot be selected:

    ✗ session_filesystem  (blocked by constraint)

Example output

  SPL Configurator -- sample_splent_spl
  ───────────────────────────────────────────────────────

  Mandatory (auto-selected):
    ✓ auth
    ✓ public

  WebFramework  (pick exactly one)
    1) flask
    2) django (blocked by constraint)
  Select [1-2]: 1
  → flask

  Optional features:

  Include admin? (requires: + auth)  [y/N]: y
  Include mail?  [y/N]: y
  Include confirmemail? (requires: auth ✓)  [y/N]: y
  Include profile? (requires: auth ✓)  [y/N]: y
  Include redis?  [y/N]: y
  Include session_redis? (requires: + redis)  [y/N]: y

  ─── Configuration ───

    ✓ auth  (mandatory)
    ✓ public  (mandatory)
    ✓ admin
    ✓ confirmemail
    ✓ mail
    ✓ profile
    ✓ redis
    ✓ session_redis
    · session_filesystem

  Validating configuration... satisfiable

  Apply this configuration? (attach features to product) [y/N]: y

    splent-io/splent_feature_auth@v1.5.3
    splent-io/splent_feature_public@v1.5.2
    splent-io/splent_feature_admin@v1.0.1
    splent-io/splent_feature_confirmemail@v1.2.10
    splent-io/splent_feature_mail@v1.3.2
    splent-io/splent_feature_profile@v1.5.2
    splent-io/splent_feature_redis@v1.5.2
    splent-io/splent_feature_session_redis@v1.0.1

  Configuration applied.

  Next: download and link features with:
     splent product:resolve

Version resolution

When applying the configuration, the command resolves a version for each selected feature:

Cache first – looks in .splent_cache/features/<org>/ for the highest versioned directory
PyPI fallback – queries pip index versions <package> if not cached
Editable – if no version is found, the feature is written without a version (editable mode)

Validation

Before applying, the configuration is validated with Flamapy’s SAT solver against the full UVL model. If the configuration is unsatisfiable (e.g., conflicting constraints), the command reports the error and exits without writing.

Requirements

SPLENT_APP must be set (a product must be selected)
[tool.splent].spl must be set in the product’s pyproject.toml
The SPL must exist in splent_catalog/ with a valid UVL file
Flamapy must be installed (pip install flamapy)

UVL alignment

The configurator is aligned with the UVL specification (Benavides et al., JSS 2025):

UVL concept	Implementation
Table 1: group semantics	mandatory, optional, alternative, or, cardinality
Fig. 4-5: metamodel	SPLModel, SPLFeature, SPLGroup
Fig. 7-9: cross-tree constraints	implies, excludes, equivalence (A <=> B)
Section 5.2: feature cardinality	Recognised and displayed; clone semantics not yet implemented