fix(codegen): recursively resolve nested fragment spreads in generated documents

[wax911]

Description

Fixes #423. The codegen FragmentResolver only inlined fragment references directly referenced from the operation document. When a fragment transitively referenced other fragments (e.g. MediaCoreFragment spreads MediaTitleFragment), those nested spreads were left as unresolved ...FragmentName in the generated document, producing invalid GraphQL requests.

Root Cause

flattenFragments() used collectReferencedNames(document) which only collected fragment spreads from the operation document itself. Then relevantDefinitions was filtered to only those directly-referenced names — excluding any fragments only reachable through nested spreads inside fragment definitions.

Fix (Option A — Recursive Inline)

Replaced the shallow single-pass approach with a 4-phase resolution:

Phase	Method	What it does
1	computeReachableFragments	BFS from operation → fragment definitions → nested definitions, computing full transitive closure. Missing fragment definitions throw at build time.
2	detectCycles	DFS with inStack/visited over reachable fragments. Cycles at any depth are rejected.
3	AstTransformer inlining	Replaces FragmentSpread → InlineFragment using the full transitive closure for relevantDefinitions. AstTransformer recurses into children automatically. Directives (@include, @skip) from the original spread are preserved on the generated inline fragment.
4	Invariant check	AST walk to verify zero FragmentSpread nodes remain (defensive guard).

Tests

19 tests total (6 existing + 13 new):

• Transitive nested (operation → Parent → Child)
• Deep transitive chain (3+ levels)
• Sibling nested fragments (one parent, multiple children)
• Shared nested fragment across multiple operations
• Missing nested fragment → build error
• Cycles through transitive references → build error
• Variable preservation through transitive inlining
• Independent operation resolution
• No-spread operation with available fragments
• Directive preservation: @include(if: $enabled)
• Directive preservation: @skip(if: $skip)
• No-directive spread baseline

Validation

• All 19 tests pass
• Full :codegen-core:test suite passes
• App module codegen regenerated: 8 operation documents produced with zero unresolved named fragment spreads (all inlined to ... on TypeName { fields })
• No changes to :runtime, :api, or any other module

Notes

• The .slim/deepwork/issue-423-progress.md file tracks the deepwork session; feel free to remove if not part of project conventions.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Enhancement (Improve existing functionality)

[codacy-production]

Up to standards ✅

🟢 Issues 0 issues

Results:
0 new issues

View in Codacy

🟢 Metrics 26 complexity · 8 duplication

Metric	Results
Complexity	26
Duplication	8

View in Codacy

_{NEW Get contextual insights on your PRs based on Codacy's metrics, along with PR and Jira context, without leaving GitHub. Enable AI reviewer
TIP This summary will be updated as you push new changes.}

[wax911]

One remaining blocker before merge: directive preservation during inline replacement.

The current code replaces a named fragment spread with an inline fragment using only the fragment definition type condition and selection set. That appears to drop directives attached to the original spread.

Example: a spread using @include(if: $enabled) should become an inline fragment that still has @include(if: $enabled). Otherwise the generated document changes query semantics.

Please carry the original spread directives onto the generated inline fragment and add a regression test for @include or @skip on a named fragment spread.

The rest of the PR looks aligned with #423: transitive reachability, missing nested fragment failure, cycle detection, sibling fragments, shared fragments, variable preservation, and independent operation resolution are covered.

[wax911]

Addressed the directive preservation review comment:

• Fix: The InlineFragment builder now carries node.directives from the original FragmentSpread onto the generated InlineFragment. Spreads using @include(if: \$enabled) or @skip(if: \$skip) will retain those directives after inlining.
• Tests added: 3 new regression tests — @include preservation, @skip preservation, and a no-directive spread baseline.

[github-actions]

Auto approved automated PR