fallow_graph/graph/
public_exports.rs

1//! Exports-aware public-export-key computation (the hard 80% of 6.A).
2//!
3//! Given the set of *public-API entry points* (the `package.json` `exports`-mapped
4//! modules plus the no-`exports` source-index fallback; computed in core's
5//! `public_api_package_entry_points`, which already encodes rule R4), this
6//! resolves the set of export symbols reachable through that public surface and
7//! returns one stable `"<rel_path>::<name>"` key per public export.
8//!
9//! A name is public when it resolves to one unique value binding on a public-API
10//! entry point. Candidates come from the entry's own exports and its `export *`
11//! closure. Shadowed and ambiguous star names are not public bindings.
12//!
13//! Keying on the surface AS EXPOSED (the entry's own name, e.g. `index.js::pub`),
14//! not the origin's internal name (`src/impl.ts::pub`), is what makes the delta
15//! exports-aware and avoids double-counting one symbol on both the barrel and
16//! the origin. A symbol re-exported only through an INTERNAL barrel that is not
17//! in `exports` never resolves on a public entry, so it produces
18//! ZERO public-API delta (the Aisha repro); one re-exported through the
19//! `exports`-mapped entry lands on that entry once (exactly one). This mirrors
20//! the exports-aware reachability the `unprovided-inject` and
21//! `unrendered-component` detectors use, kept in the graph crate so the review
22//! brief (cli) can call it directly off the retained graph.
23
24use std::path::Path;
25
26use super::relativize;
27
28use fallow_types::discover::FileId;
29use rustc_hash::FxHashSet;
30
31use super::{EffectiveExportBinding, EffectiveExportResolution, ExportNamespace, ModuleGraph};
32
33/// Direct declaration exposed through at least one public package entry.
34#[derive(Debug, Clone, PartialEq, Eq, Hash)]
35pub struct PublicExportOrigin {
36    file_id: FileId,
37    export_name: String,
38}
39
40impl PublicExportOrigin {
41    /// Module that owns the public declaration.
42    #[must_use]
43    pub const fn file_id(&self) -> FileId {
44        self.file_id
45    }
46
47    /// Name of the declaration in its owning module.
48    #[must_use]
49    pub fn export_name(&self) -> &str {
50        &self.export_name
51    }
52}
53
54impl ModuleGraph {
55    /// Compute the set of public-export keys reachable through the given
56    /// `public_api_entry_points` (an exports-aware set; see module docs).
57    ///
58    /// Keys are `"<root-relative forward-slashed path>::<export name>"`.
59    /// Type-only exports are skipped: a type erased at build carries no runtime
60    /// contract, so it never widens the public *value* surface that 6.A tracks.
61    #[must_use]
62    pub fn public_export_keys(
63        &self,
64        public_api_entry_points: &FxHashSet<FileId>,
65        root: &Path,
66    ) -> FxHashSet<String> {
67        let candidate_names = self.public_value_export_names(public_api_entry_points);
68        let mut keys: FxHashSet<String> = FxHashSet::default();
69
70        for entry_id in public_api_entry_points {
71            let Some(entry) = self.modules.get(entry_id.0 as usize) else {
72                continue;
73            };
74            let rel = relativize(&entry.path, root);
75            for name in &candidate_names {
76                if matches!(
77                    self.resolve_export(*entry_id, name, ExportNamespace::Value),
78                    EffectiveExportResolution::Unique(_)
79                ) {
80                    keys.insert(format!("{rel}::{name}"));
81                }
82            }
83        }
84        keys
85    }
86
87    /// Resolve the direct declarations exposed through public package entries.
88    /// Shadowed and ambiguous star candidates contribute no origins.
89    #[must_use]
90    pub fn public_export_origins(
91        &self,
92        public_api_entry_points: &FxHashSet<FileId>,
93    ) -> FxHashSet<PublicExportOrigin> {
94        self.public_export_origins_in_namespace(public_api_entry_points, ExportNamespace::Value)
95    }
96
97    /// Resolve direct declarations exposed through public package entries in
98    /// one export namespace.
99    ///
100    /// Type-only public surfaces matter to structural consumers such as class
101    /// member analysis, while runtime consumers can continue to request only
102    /// the value namespace.
103    #[must_use]
104    pub fn public_export_origins_in_namespace(
105        &self,
106        public_api_entry_points: &FxHashSet<FileId>,
107        namespace: ExportNamespace,
108    ) -> FxHashSet<PublicExportOrigin> {
109        self.public_export_declaration_bindings_in_namespace(public_api_entry_points, namespace)
110            .into_iter()
111            .filter_map(|binding| self.export_binding_origin(binding))
112            .map(|origin| PublicExportOrigin {
113                file_id: origin.file_id(),
114                export_name: origin.export().name.to_string(),
115            })
116            .collect()
117    }
118
119    /// Unique value bindings exposed through at least one public package entry.
120    #[must_use]
121    pub fn public_export_bindings(
122        &self,
123        public_api_entry_points: &FxHashSet<FileId>,
124    ) -> FxHashSet<EffectiveExportBinding> {
125        self.public_export_bindings_in_namespace(public_api_entry_points, ExportNamespace::Value)
126    }
127
128    fn public_export_bindings_in_namespace(
129        &self,
130        public_api_entry_points: &FxHashSet<FileId>,
131        namespace: ExportNamespace,
132    ) -> FxHashSet<EffectiveExportBinding> {
133        let candidate_names = self.public_export_names(public_api_entry_points, namespace);
134        public_api_entry_points
135            .iter()
136            .flat_map(|entry| {
137                candidate_names.iter().filter_map(|name| {
138                    match self.resolve_export(*entry, name, namespace) {
139                        EffectiveExportResolution::Unique(binding) => Some(binding),
140                        EffectiveExportResolution::Missing
141                        | EffectiveExportResolution::Ambiguous => None,
142                    }
143                })
144            })
145            .collect()
146    }
147
148    /// Direct declaration bindings exposed through public entries, including
149    /// declarations nested under public namespace-object exports.
150    fn public_export_declaration_bindings_in_namespace(
151        &self,
152        public_api_entry_points: &FxHashSet<FileId>,
153        namespace: ExportNamespace,
154    ) -> FxHashSet<EffectiveExportBinding> {
155        let mut declarations = FxHashSet::default();
156        let mut visited = FxHashSet::default();
157        let mut stack: Vec<_> = self
158            .public_export_bindings_in_namespace(public_api_entry_points, namespace)
159            .into_iter()
160            .collect();
161        while let Some(binding) = stack.pop() {
162            if !visited.insert(binding) {
163                continue;
164            }
165            if let Some(source) = binding.namespace_source() {
166                stack.extend(self.unique_export_bindings(source, namespace));
167            } else if self.export_binding_origin(binding).is_some() {
168                declarations.insert(binding);
169            }
170        }
171        declarations
172    }
173
174    fn public_value_export_names(
175        &self,
176        public_api_entry_points: &FxHashSet<FileId>,
177    ) -> FxHashSet<String> {
178        self.public_export_names(public_api_entry_points, ExportNamespace::Value)
179    }
180
181    fn public_export_names(
182        &self,
183        public_api_entry_points: &FxHashSet<FileId>,
184        namespace: ExportNamespace,
185    ) -> FxHashSet<String> {
186        let star_targets = self.public_star_re_export_targets(public_api_entry_points);
187        let mut names: FxHashSet<String> = public_api_entry_points
188            .iter()
189            .chain(star_targets.iter())
190            .filter_map(|id| self.modules.get(id.0 as usize))
191            .flat_map(|module| &module.exports)
192            .filter(|export| namespace == ExportNamespace::Type || !export.is_type_only)
193            .map(|export| export.name.to_string())
194            .collect();
195        names.insert("default".to_string());
196        names
197    }
198
199    /// The `export *` closure rooted at the public-API entry points: every module
200    /// reachable through a chain of `export * from './x'` edges starting from a
201    /// public entry. Their exported names are candidates for effective
202    /// resolution on each public entry.
203    fn public_star_re_export_targets(
204        &self,
205        public_api_entry_points: &FxHashSet<FileId>,
206    ) -> FxHashSet<FileId> {
207        let mut targets: FxHashSet<FileId> = public_api_entry_points
208            .iter()
209            .filter_map(|id| self.modules.get(id.0 as usize))
210            .flat_map(|module| {
211                module
212                    .re_exports
213                    .iter()
214                    .filter(|re| re.exported_name == "*")
215                    .map(|re| re.source_file)
216            })
217            .collect();
218
219        let mut stack: Vec<FileId> = targets.iter().copied().collect();
220        while let Some(id) = stack.pop() {
221            let Some(module) = self.modules.get(id.0 as usize) else {
222                continue;
223            };
224            for re in module
225                .re_exports
226                .iter()
227                .filter(|re| re.exported_name == "*")
228            {
229                if targets.insert(re.source_file) {
230                    stack.push(re.source_file);
231                }
232            }
233        }
234        targets
235    }
236}
237
238#[cfg(test)]
239mod tests {
240    use super::*;
241    use crate::resolve::{ResolveResult, ResolvedImport, ResolvedModule, ResolvedReExport};
242    use fallow_types::discover::{DiscoveredFile, EntryPoint, EntryPointSource};
243    use fallow_types::extract::{
244        ExportInfo, ExportName, ImportInfo, ImportedName, ReExportInfo, VisibilityTag,
245    };
246    use std::path::PathBuf;
247
248    fn file(id: u32, path: &str) -> DiscoveredFile {
249        DiscoveredFile {
250            id: FileId(id),
251            path: PathBuf::from(path),
252            size_bytes: 10,
253        }
254    }
255
256    fn named_export(name: &str) -> ExportInfo {
257        ExportInfo {
258            name: ExportName::Named(name.to_string()),
259            local_name: Some(name.to_string()),
260            is_type_only: false,
261            visibility: VisibilityTag::None,
262            expected_unused_reason: None,
263            span: oxc_span::Span::new(0, 20),
264            members: vec![],
265            is_side_effect_used: false,
266            super_class: None,
267            deprecated: false,
268            deprecated_reason: None,
269        }
270    }
271
272    fn re_export(imported: &str, exported: &str, target: FileId) -> ResolvedReExport {
273        ResolvedReExport {
274            info: ReExportInfo {
275                source: "./impl".to_string(),
276                imported_name: imported.to_string(),
277                exported_name: exported.to_string(),
278                is_type_only: false,
279                span: oxc_span::Span::new(0, 10),
280                statement_span: oxc_span::Span::new(0, 0),
281                source_span: oxc_span::Span::new(0, 0),
282            },
283            target: ResolveResult::InternalModule(target),
284        }
285    }
286
287    fn named_import(name: &str, target: FileId) -> ResolvedImport {
288        ResolvedImport {
289            info: ImportInfo {
290                source: "./x".to_string(),
291                imported_name: ImportedName::Named(name.to_string()),
292                local_name: name.to_string(),
293                is_type_only: false,
294                is_type_only_star: false,
295                from_style: false,
296                span: oxc_span::Span::new(0, 10),
297                source_span: oxc_span::Span::default(),
298            },
299            target: ResolveResult::InternalModule(target),
300        }
301    }
302
303    /// index (0, the exports entry) re-exports `pub` from impl (1, NOT public);
304    /// internal-barrel (2) re-exports `priv` from impl. consumer (3) imports both.
305    fn build_graph() -> (ModuleGraph, FxHashSet<FileId>) {
306        let files = vec![
307            file(0, "/p/index.js"),
308            file(1, "/p/src/impl.ts"),
309            file(2, "/p/src/internal.ts"),
310            file(3, "/p/src/consumer.ts"),
311        ];
312        let entry_points = vec![EntryPoint {
313            path: PathBuf::from("/p/index.js"),
314            source: EntryPointSource::PackageJsonExports,
315        }];
316        let resolved = vec![
317            ResolvedModule {
318                file_id: FileId(0),
319                path: PathBuf::from("/p/index.js"),
320                re_exports: vec![re_export("pub", "pub", FileId(1))],
321                ..Default::default()
322            },
323            ResolvedModule {
324                file_id: FileId(1),
325                path: PathBuf::from("/p/src/impl.ts"),
326                exports: vec![named_export("pub"), named_export("priv")].into(),
327                ..Default::default()
328            },
329            ResolvedModule {
330                file_id: FileId(2),
331                path: PathBuf::from("/p/src/internal.ts"),
332                re_exports: vec![re_export("priv", "priv", FileId(1))],
333                ..Default::default()
334            },
335            ResolvedModule {
336                file_id: FileId(3),
337                path: PathBuf::from("/p/src/consumer.ts"),
338                resolved_imports: vec![
339                    named_import("pub", FileId(0)),
340                    named_import("priv", FileId(2)),
341                ],
342                ..Default::default()
343            },
344        ];
345        let graph = ModuleGraph::build(&resolved, &entry_points, &files);
346        // The exports-mapped entry set: only index.js (PackageJsonExports).
347        let public_entries: FxHashSet<FileId> = std::iter::once(FileId(0)).collect();
348        (graph, public_entries)
349    }
350
351    #[test]
352    fn export_reexported_through_exports_path_is_public() {
353        let (graph, public_entries) = build_graph();
354        let keys = graph.public_export_keys(&public_entries, Path::new("/p"));
355        // `pub` is re-exported through the exports-mapped index.js, so it appears
356        // on the public surface keyed at the entry (the exposed name), not the
357        // internal origin.
358        assert!(
359            keys.contains("index.js::pub"),
360            "exports-reachable symbol must be public: {keys:?}"
361        );
362    }
363
364    #[test]
365    fn export_reexported_only_through_internal_barrel_is_not_public() {
366        let (graph, public_entries) = build_graph();
367        let keys = graph.public_export_keys(&public_entries, Path::new("/p"));
368        // `priv` reaches a consumer ONLY through the internal (non-exports)
369        // barrel, so it is on no public-surface key (neither the entry nor a
370        // star-target).
371        assert!(
372            !keys.iter().any(|k| k.ends_with("::priv")),
373            "internal-barrel-only symbol must NOT be public: {keys:?}"
374        );
375    }
376
377    /// Build the Aisha-repro graph parameterized by which impl symbols exist and
378    /// which is re-exported through the exports-mapped `index.js`. `internal`
379    /// (if present) is re-exported only through the non-exports internal barrel.
380    fn build_aisha_graph(
381        impl_exports: &[&str],
382        exports_reexported: &[&str],
383        internal_reexported: &[&str],
384    ) -> (ModuleGraph, FxHashSet<FileId>) {
385        let files = vec![
386            file(0, "/p/index.js"),
387            file(1, "/p/src/impl.ts"),
388            file(2, "/p/src/internal.ts"),
389        ];
390        let entry_points = vec![EntryPoint {
391            path: PathBuf::from("/p/index.js"),
392            source: EntryPointSource::PackageJsonExports,
393        }];
394        let resolved = vec![
395            ResolvedModule {
396                file_id: FileId(0),
397                path: PathBuf::from("/p/index.js"),
398                re_exports: exports_reexported
399                    .iter()
400                    .map(|n| re_export(n, n, FileId(1)))
401                    .collect(),
402                ..Default::default()
403            },
404            ResolvedModule {
405                file_id: FileId(1),
406                path: PathBuf::from("/p/src/impl.ts"),
407                exports: impl_exports.iter().map(|n| named_export(n)).collect(),
408                ..Default::default()
409            },
410            ResolvedModule {
411                file_id: FileId(2),
412                path: PathBuf::from("/p/src/internal.ts"),
413                re_exports: internal_reexported
414                    .iter()
415                    .map(|n| re_export(n, n, FileId(1)))
416                    .collect(),
417                ..Default::default()
418            },
419        ];
420        let graph = ModuleGraph::build(&resolved, &entry_points, &files);
421        let public_entries: FxHashSet<FileId> = std::iter::once(FileId(0)).collect();
422        (graph, public_entries)
423    }
424
425    #[test]
426    fn done_condition_internal_zero_exports_one() {
427        let root = Path::new("/p");
428        // Base: impl exports `pub`, re-exported through the exports-mapped index.
429        let (base_graph, base_entries) = build_aisha_graph(&["pub"], &["pub"], &[]);
430        let base = base_graph.public_export_keys(&base_entries, root);
431
432        // Head A: add an internal-barrel symbol NOT in exports -> 0 public deltas.
433        let (head_a_graph, head_a_entries) =
434            build_aisha_graph(&["pub", "internalOnly"], &["pub"], &["internalOnly"]);
435        let head_a = head_a_graph.public_export_keys(&head_a_entries, root);
436        let internal_delta: Vec<_> = head_a.difference(&base).collect();
437        assert!(
438            internal_delta.is_empty(),
439            "internal-barrel symbol must yield ZERO public-API delta: {internal_delta:?}"
440        );
441
442        // Head B: add a symbol reachable through the exports path -> exactly 1.
443        let (head_b_graph, head_b_entries) =
444            build_aisha_graph(&["pub", "widget"], &["pub", "widget"], &[]);
445        let head_b = head_b_graph.public_export_keys(&head_b_entries, root);
446        let exports_delta: Vec<_> = head_b.difference(&base).collect();
447        assert_eq!(
448            exports_delta.len(),
449            1,
450            "exports-reachable symbol must yield EXACTLY ONE public-API delta: {exports_delta:?}"
451        );
452        assert_eq!(exports_delta[0], "index.js::widget");
453    }
454
455    #[test]
456    fn type_only_exports_are_skipped() {
457        let files = vec![file(0, "/p/index.ts")];
458        let entry_points = vec![EntryPoint {
459            path: PathBuf::from("/p/index.ts"),
460            source: EntryPointSource::PackageJsonExports,
461        }];
462        let mut type_export = named_export("T");
463        type_export.is_type_only = true;
464        let resolved = vec![ResolvedModule {
465            file_id: FileId(0),
466            path: PathBuf::from("/p/index.ts"),
467            exports: vec![type_export, named_export("v")].into(),
468            ..Default::default()
469        }];
470        let graph = ModuleGraph::build(&resolved, &entry_points, &files);
471        let public_entries: FxHashSet<FileId> = std::iter::once(FileId(0)).collect();
472        let keys = graph.public_export_keys(&public_entries, Path::new("/p"));
473        assert!(keys.contains("index.ts::v"));
474        assert!(!keys.contains("index.ts::T"), "type-only export skipped");
475
476        let type_origins =
477            graph.public_export_origins_in_namespace(&public_entries, ExportNamespace::Type);
478        assert!(
479            type_origins
480                .iter()
481                .any(|origin| origin.export_name() == "T"),
482            "type namespace keeps the public declaration"
483        );
484        assert!(
485            graph
486                .public_export_origins(&public_entries)
487                .iter()
488                .all(|origin| origin.export_name() != "T"),
489            "value-only consumers still exclude type-only declarations"
490        );
491    }
492
493    #[test]
494    fn public_namespace_objects_expand_to_declaration_bindings() {
495        let (graph, public_entries) = build_star_surface_graph(
496            vec![re_export("*", "SDK", FileId(1))],
497            vec![ResolvedModule {
498                file_id: FileId(1),
499                path: PathBuf::from("/p/sdk.ts"),
500                exports: vec![named_export("Client")].into(),
501                ..Default::default()
502            }],
503        );
504
505        let declarations = graph.public_export_declaration_bindings_in_namespace(
506            &public_entries,
507            ExportNamespace::Value,
508        );
509
510        assert_eq!(declarations.len(), 1);
511        let binding = *declarations.iter().next().expect("public Client binding");
512        let origin = graph.export_binding_origin(binding).expect("direct origin");
513        assert_eq!(origin.file_id(), FileId(1));
514        assert_eq!(origin.export().name.to_string(), "Client");
515    }
516
517    fn build_star_surface_graph(
518        entry_re_exports: Vec<ResolvedReExport>,
519        source_modules: Vec<ResolvedModule>,
520    ) -> (ModuleGraph, FxHashSet<FileId>) {
521        let mut files = vec![file(0, "/p/index.ts")];
522        files.extend(source_modules.iter().map(|module| {
523            file(
524                module.file_id.0,
525                module.path.to_str().expect("test path is UTF-8"),
526            )
527        }));
528        let entry_points = vec![EntryPoint {
529            path: PathBuf::from("/p/index.ts"),
530            source: EntryPointSource::PackageJsonExports,
531        }];
532        let mut resolved = vec![ResolvedModule {
533            file_id: FileId(0),
534            path: PathBuf::from("/p/index.ts"),
535            re_exports: entry_re_exports,
536            ..Default::default()
537        }];
538        resolved.extend(source_modules);
539        let graph = ModuleGraph::build(&resolved, &entry_points, &files);
540        (graph, std::iter::once(FileId(0)).collect())
541    }
542
543    #[test]
544    fn explicit_export_hides_shadowed_star_binding_from_public_surface() {
545        let (graph, public_entries) = build_star_surface_graph(
546            vec![
547                re_export("*", "*", FileId(1)),
548                re_export("foo", "foo", FileId(2)),
549            ],
550            vec![
551                ResolvedModule {
552                    file_id: FileId(1),
553                    path: PathBuf::from("/p/star-source.ts"),
554                    exports: vec![named_export("foo")].into(),
555                    ..Default::default()
556                },
557                ResolvedModule {
558                    file_id: FileId(2),
559                    path: PathBuf::from("/p/explicit-source.ts"),
560                    exports: vec![named_export("foo")].into(),
561                    ..Default::default()
562                },
563            ],
564        );
565
566        let keys = graph.public_export_keys(&public_entries, Path::new("/p"));
567
568        assert_eq!(keys, FxHashSet::from_iter(["index.ts::foo".to_string()]));
569    }
570
571    #[test]
572    fn ambiguous_star_binding_is_absent_from_public_surface() {
573        let (graph, public_entries) = build_star_surface_graph(
574            vec![
575                re_export("*", "*", FileId(1)),
576                re_export("*", "*", FileId(2)),
577            ],
578            vec![
579                ResolvedModule {
580                    file_id: FileId(1),
581                    path: PathBuf::from("/p/left.ts"),
582                    exports: vec![named_export("foo")].into(),
583                    ..Default::default()
584                },
585                ResolvedModule {
586                    file_id: FileId(2),
587                    path: PathBuf::from("/p/right.ts"),
588                    exports: vec![named_export("foo")].into(),
589                    ..Default::default()
590                },
591            ],
592        );
593
594        let keys = graph.public_export_keys(&public_entries, Path::new("/p"));
595
596        assert!(
597            keys.is_empty(),
598            "ambiguous foo is not a public binding: {keys:?}"
599        );
600    }
601
602    #[test]
603    fn convergent_star_diamond_has_one_exposed_public_key() {
604        let (graph, public_entries) = build_star_surface_graph(
605            vec![
606                re_export("*", "*", FileId(1)),
607                re_export("*", "*", FileId(2)),
608            ],
609            vec![
610                ResolvedModule {
611                    file_id: FileId(1),
612                    path: PathBuf::from("/p/left.ts"),
613                    re_exports: vec![re_export("*", "*", FileId(3))],
614                    ..Default::default()
615                },
616                ResolvedModule {
617                    file_id: FileId(2),
618                    path: PathBuf::from("/p/right.ts"),
619                    re_exports: vec![re_export("*", "*", FileId(3))],
620                    ..Default::default()
621                },
622                ResolvedModule {
623                    file_id: FileId(3),
624                    path: PathBuf::from("/p/source.ts"),
625                    exports: vec![named_export("foo")].into(),
626                    ..Default::default()
627                },
628            ],
629        );
630
631        let keys = graph.public_export_keys(&public_entries, Path::new("/p"));
632
633        assert_eq!(keys, FxHashSet::from_iter(["index.ts::foo".to_string()]));
634    }
635
636    #[test]
637    fn public_surface_preserves_aliases_default_and_value_namespace() {
638        let mut default_export = named_export("Widget");
639        default_export.name = ExportName::Default;
640        let mut type_export = named_export("T");
641        type_export.is_type_only = true;
642        let mut type_re_export = re_export("T", "PublicType", FileId(1));
643        type_re_export.info.is_type_only = true;
644        let (graph, public_entries) = build_star_surface_graph(
645            vec![
646                re_export("default", "default", FileId(1)),
647                re_export("default", "Widget", FileId(1)),
648                type_re_export,
649            ],
650            vec![ResolvedModule {
651                file_id: FileId(1),
652                path: PathBuf::from("/p/widget.ts"),
653                exports: vec![default_export, type_export].into(),
654                ..Default::default()
655            }],
656        );
657
658        let keys = graph.public_export_keys(&public_entries, Path::new("/p"));
659
660        assert_eq!(
661            keys,
662            FxHashSet::from_iter([
663                "index.ts::default".to_string(),
664                "index.ts::Widget".to_string(),
665            ])
666        );
667    }
668}
fallow_graph/graph/public_exports.rs

fallow_graph/graph/
public_exports.rs
