feat: Add GetFeatureByName and GetSegmentByName

[matthewelwell]

Adds lookups by name for features and segments, so callers that know a project UUID and a name — but not a UUID — can resolve an entity.

This unblocks terraform-provider-flagsmith#153, which asks for flagsmith_feature and flagsmith_segment data sources so that features created outside of Terraform can be referenced.

func (c *Client) GetFeatureByName(projectUUID, featureName string) (*Feature, error)
func (c *Client) GetSegmentByName(projectUUID, segmentName string) (*Segment, error)

Things worth knowing about the API

Both are built on a shared searchProjectResources helper, because two API details make this less trivial than it looks:

• Features filter on search, segments filter on q. Passing the wrong param is silently ignored and returns every result in the project.
• Both filters are case-insensitive contains matches, so results have to be filtered client-side for an exact match. Without that, asking for flag could resolve to flagship.

Pages are requested as page=N against the client's configured base URL rather than by following DRF's next link, which is built from the incoming request host and so can be unreachable behind a self-hosted reverse proxy. next is used only as a "there is more" signal.

ProjectUUID is set from the argument, since the API never returns it. The Terraform provider depends on this: a data source read whose required attributes don't echo the configuration is rejected by Terraform core.

Duplicate names

Segment names are not unique within a project (Segment.Meta has no constraint), so a name matching more than one segment returns MultipleSegmentsFoundError rather than picking arbitrarily. Feature names are uniquely indexed, so MultipleFeaturesFoundError is defensive only — but it fails loudly rather than silently choosing a row if that invariant ever changes.

Tests

19 new unit tests in search_test.go covering exact-match filtering, partial-match-only, case sensitivity, pagination, duplicate matches, API errors, an unresolvable project, the segment rules tree, feature-specific segments, and that the search/q params and ProjectUUID stamping are correct. No existing behaviour changes.

Release

Needs a v0.12.0 tag once merged, so the Terraform provider can depend on it.

🤖 Generated with Claude Code

[matthewelwell]

Superseded: the Terraform provider data sources are now keyed on uuid (see terraform-provider-flagsmith#244), which GetFeature and GetSegment already cover on v0.11.1. No client change is needed for that issue after all.

Lookup by name is still a reasonable addition if it's wanted later — the branch is kept for reference. The two API details it dealt with are worth recording either way: features filter on search while segments filter on q, and both are case-insensitive contains matches, so exact matching has to happen client-side.