feat(compose): flag composables and resolve @Preview into PREVIEWS edges - #1624

Adds two Compose-aware facts to the graph: is_composable on Function, and a PREVIEWS edge from each @Preview function to the composable it renders. Now also fixes #1602 at source, which this PR previously only worked around.

Both Compose facts exist to answer questions that are currently unanswerable. A Compose UI tree is a call graph of @Composable functions and nothing marks them as such; and a @Preview function looks exactly like dead code — nothing calls it, because the IDE and the Compose tooling do.

is_composable

Set from an anchored module-level match, ^@Composable\b. Anchored and word-bounded on purpose: a substring test would also match @NonComposable-style names, and \b keeps it from matching a longer annotation that merely starts with the same letters.

Declared in all three places the Kuzu backend requires — node-table declaration, SCHEMA_MAP allow-list, and simple_migrations. Missing any one of the three loses the property with no error: CREATE NODE TABLE on an existing database throws "already exists" and is swallowed, and SCHEMA_MAP is an allow-list whose misses are dropped silently at write time. The failure mode is that Kuzu quietly lacks the property while schemaless backends have it, so the two backends disagree and nothing reports it.

PREVIEWS

FROM Function TO Function. Source is the @Preview-annotated function, target is the composable it calls.

Annotation matching strips arguments down to the bare name and compares for equality against "Preview". That's the word-boundary-safe equivalent of the is_composable regex, and it's why PreviewParameter and PreviewScreenSizes are correctly excluded without needing a second annotation-name parser.

Resolution is scoped to calls in the preview function's own body, so an unrelated call (a logging helper, say) isn't mistaken for the previewed composable.

Second commit: fixing #1602 rather than working around it

KOTLIN_QUERIES["calls"] captures constructor_invocation nodes — and an annotation carrying arguments is a constructor_invocation in this grammar. So @Preview(showBackground = true) on fun GreetingPreview() was recorded as a call, from GreetingPreview, named Preview.

The echo also reached expressions inside the argument list: @PreviewParameter(provider = FooProvider::class) contributes a callable_reference capture. That's why a preview function appeared to call itself and every type named anywhere in its own annotations.

The first version of this PR filtered these annotation-echo rows inside build_previews_links and left the parser alone. That was the wrong layer — the phantoms are present in function_calls for Kotlin generally, not only under Compose. The second commit filters at source instead.

The discriminator is the parse tree, not the name. _is_within_annotation walks ancestors looking for an annotation node:

A filter keyed on the node type alone would have deleted the last two — every superclass-construction and constructor-delegation edge in the Kotlin graph. The regression guards for both are in the test class.

Two node types are accepted, not one. Declaration-level annotations nest under annotation, which covers functions, classes, objects, interfaces, typealiases, properties, and use-site targets like @field:ColumnInfo(...) and @get:JvmName(...). File-level annotations are the exception — @file:JvmName("Utils") produces file_annotation with no annotation anywhere in the chain, so checking only annotation would have left the phantom at the top of every file using a @file: target. Each position has a test.

build_previews_links keeps its own_decorator_names rejection as a backstop rather than dropping it now that the parser is clean. It costs one set lookup, and its test feeds hand-built rows rather than parser output, so it still pins a real invariant. The docstring now says the parser filters at source.

Golden refresh

The Kotlin golden was already stale on this branch before the fix commit — AndroidAnnotations.kt gained the compose functions, shifting line numbers for UserViewModel, UserEntity, PlainHelper and findAll. tests/integration/test_parser_goldens.py -k kotlin was red on the first commit and is green now. (This is the refresh @Shashankss1205 flagged on #1623 as owed by this PR.)

Unlike every previous golden refresh in this series, this one removes edges, so I regenerated twice — once without the fix, once with — to isolate what the fix itself changes:

                without fix -> with fix
CALLS                    28 ->   24   (-4)
BINDS                     2 ->    2
COMPANION_OF              2 ->    2
CONTAINS                249 ->  249
HAS_PARAMETER            26 ->   26
IMPORTS                   2 ->    2
INHERITS                 11 ->   11
PREVIEWS                  2 ->    2
nodes                   244 ->  244

Only CALLS moves. At parser level the fix drops 6 phantom rows across the fixture, of which 4 had resolved into graph edges:

AndroidAnnotations.kt   'Preview' from GreetingPreview
                        'Entity'  from UserEntity
                        'Query'   from findAll
Annotations.kt          'Fancy'   from Foo, from baz (x2)

Three of the six are in Annotations.kt — a plain, non-Android Kotlin fixture using @Fancy(...) — which confirms the bug was never Compose- or Android-specific.

Verification

Measured on this branch, on macOS:

tests/unit          3 failed, 1246 passed, 19 skipped
tests/integration              45 passed

Baseline on the first commit of this PR was 3 failed, 1238 passed — the same 3 failures, +8 new tests. Those 3 are #1608 (tempfile returns /var/… while the parser resolves to /private/var/…); they reproduce on a clean checkout of main and are unrelated to this PR. Integration was red before the fix commit (stale golden) and is green after.

The fixture declares @Composable/@Preview as local stub annotations, so no Compose compiler or Android SDK is needed on the test path. Tests cover the negative cases directly: @PreviewParameter must not be treated as @Preview, and the self-edge from the annotation echo must not appear.

Commits

db56984  feat(compose): flag composables and resolve @Preview into PREVIEWS edges
bbd67db  fix(parsers/kotlin): stop recording annotations as function calls (#1602)

Last of the five-PR Android/Kotlin series; its three prerequisites (#1620, #1622, #1623) have merged, and #1621 (gradle) was independent and has also merged.

Closes #1602