From 72d015e263581cb7602bb5f7036c3416867ebeb6 Mon Sep 17 00:00:00 2001
From: Joey Perrott <josephperrott@gmail.com>
Date: Tue, 18 Feb 2025 15:23:45 +0000
Subject: [PATCH] feat(bazel): create strict_deps test for ts_project based
 build targets

Checks to ensure that all of the dependencies relied on within the ts_project sources are directly
provided as dependencies within that target, rather than being provided transitively.
---
 bazel/BUILD.bazel                             |   1 +
 bazel/ts_project/BUILD.bazel                  |   9 ++
 bazel/ts_project/index.bzl                    |   3 +
 bazel/ts_project/strict_deps/BUILD.bazel      |  26 ++++
 bazel/ts_project/strict_deps/diagnostic.mts   |  12 ++
 bazel/ts_project/strict_deps/index.bzl        | 135 ++++++++++++++++++
 bazel/ts_project/strict_deps/index.mts        |  77 ++++++++++
 bazel/ts_project/strict_deps/manifest.mts     |   5 +
 bazel/ts_project/strict_deps/test/BUILD.bazel |  56 ++++++++
 .../strict_deps/test/depth/BUILD.bazel        |   8 ++
 .../ts_project/strict_deps/test/depth/file.ts |   1 +
 .../strict_deps/test/depth/tsconfig.json      |   7 +
 .../strict_deps/test/import_from_depth.ts     |   3 +
 .../strict_deps/test/import_node_module.ts    |   4 +
 .../strict_deps/test/import_npm_module.ts     |   3 +
 .../test/import_npm_module/BUILD.bazel        |  10 ++
 .../test/import_npm_module/index.ts           |   3 +
 .../test/import_npm_module/tsconfig.json      |   6 +
 .../test/sibling_import_from_depth.ts         |   3 +
 .../strict_deps/test/transitive_from_depth.ts |   1 +
 .../ts_project/strict_deps/test/tsconfig.json |   6 +
 bazel/ts_project/strict_deps/tsconfig.json    |   9 ++
 bazel/ts_project/strict_deps/visitor.mts      |  40 ++++++
 23 files changed, 428 insertions(+)
 create mode 100644 bazel/ts_project/BUILD.bazel
 create mode 100644 bazel/ts_project/index.bzl
 create mode 100644 bazel/ts_project/strict_deps/BUILD.bazel
 create mode 100644 bazel/ts_project/strict_deps/diagnostic.mts
 create mode 100644 bazel/ts_project/strict_deps/index.bzl
 create mode 100644 bazel/ts_project/strict_deps/index.mts
 create mode 100644 bazel/ts_project/strict_deps/manifest.mts
 create mode 100644 bazel/ts_project/strict_deps/test/BUILD.bazel
 create mode 100644 bazel/ts_project/strict_deps/test/depth/BUILD.bazel
 create mode 100644 bazel/ts_project/strict_deps/test/depth/file.ts
 create mode 100644 bazel/ts_project/strict_deps/test/depth/tsconfig.json
 create mode 100644 bazel/ts_project/strict_deps/test/import_from_depth.ts
 create mode 100644 bazel/ts_project/strict_deps/test/import_node_module.ts
 create mode 100644 bazel/ts_project/strict_deps/test/import_npm_module.ts
 create mode 100644 bazel/ts_project/strict_deps/test/import_npm_module/BUILD.bazel
 create mode 100644 bazel/ts_project/strict_deps/test/import_npm_module/index.ts
 create mode 100644 bazel/ts_project/strict_deps/test/import_npm_module/tsconfig.json
 create mode 100644 bazel/ts_project/strict_deps/test/sibling_import_from_depth.ts
 create mode 100644 bazel/ts_project/strict_deps/test/transitive_from_depth.ts
 create mode 100644 bazel/ts_project/strict_deps/test/tsconfig.json
 create mode 100644 bazel/ts_project/strict_deps/tsconfig.json
 create mode 100644 bazel/ts_project/strict_deps/visitor.mts

diff --git a/bazel/BUILD.bazel b/bazel/BUILD.bazel
index 927517910..34d85382f 100644
--- a/bazel/BUILD.bazel
+++ b/bazel/BUILD.bazel
@@ -33,6 +33,7 @@ filegroup(
         "//bazel/private:files",
         "//bazel/remote-execution:files",
         "//bazel/spec-bundling:files",
+        "//bazel/ts_project:files",
     ],
     visibility = ["//:npm"],
 )
diff --git a/bazel/ts_project/BUILD.bazel b/bazel/ts_project/BUILD.bazel
new file mode 100644
index 000000000..e25fbc468
--- /dev/null
+++ b/bazel/ts_project/BUILD.bazel
@@ -0,0 +1,9 @@
+package(default_visibility = ["//visibility:public"])
+
+# Make source files available for distribution
+filegroup(
+    name = "files",
+    srcs = glob(["*"]) + [
+        "//bazel/ts_project/strict_deps:files",
+    ],
+)
diff --git a/bazel/ts_project/index.bzl b/bazel/ts_project/index.bzl
new file mode 100644
index 000000000..8bce3696f
--- /dev/null
+++ b/bazel/ts_project/index.bzl
@@ -0,0 +1,3 @@
+load("//bazel/ts_project/strict_deps:index.bzl", _strict_deps_test = "strict_deps_test")
+
+strict_deps_test = _strict_deps_test
diff --git a/bazel/ts_project/strict_deps/BUILD.bazel b/bazel/ts_project/strict_deps/BUILD.bazel
new file mode 100644
index 000000000..8ca3bd0a4
--- /dev/null
+++ b/bazel/ts_project/strict_deps/BUILD.bazel
@@ -0,0 +1,26 @@
+load("@aspect_rules_js//js:defs.bzl", "js_binary")
+load("@aspect_rules_ts//ts:defs.bzl", "ts_project")
+
+package(default_visibility = ["//visibility:public"])
+
+# Make source files available for distribution
+filegroup(
+    name = "files",
+    srcs = glob(["*"]),
+)
+
+ts_project(
+    name = "lib",
+    srcs = glob(["*.mts"]),
+    deps = [
+        "//bazel:node_modules/@types/node",
+        "//bazel:node_modules/typescript",
+    ],
+)
+
+js_binary(
+    name = "bin",
+    data = [":lib"],
+    entry_point = ":index.mjs",
+    visibility = ["//visibility:public"],
+)
diff --git a/bazel/ts_project/strict_deps/diagnostic.mts b/bazel/ts_project/strict_deps/diagnostic.mts
new file mode 100644
index 000000000..2bc222205
--- /dev/null
+++ b/bazel/ts_project/strict_deps/diagnostic.mts
@@ -0,0 +1,12 @@
+import ts from 'typescript';
+
+export function createDiagnostic(message: string, node: ts.Node): ts.Diagnostic {
+  return {
+    category: ts.DiagnosticCategory.Error,
+    code: -1,
+    file: node.getSourceFile(),
+    start: node.getStart(),
+    length: node.getWidth(),
+    messageText: message,
+  };
+}
diff --git a/bazel/ts_project/strict_deps/index.bzl b/bazel/ts_project/strict_deps/index.bzl
new file mode 100644
index 000000000..451277c8e
--- /dev/null
+++ b/bazel/ts_project/strict_deps/index.bzl
@@ -0,0 +1,135 @@
+load("@aspect_rules_js//js:providers.bzl", "JsInfo")
+
+# A custom provider to pass along the npm package name for linked npm packages
+NpmPackage = provider()
+
+def _npm_package_aspect_impl(target, ctx):
+    if (ctx.rule.kind == "npm_link_package_store"):
+        package_name = ctx.rule.attr.package
+
+        # TODO: Determine how to include the package field information in locally built npm package targets
+        if package_name == "":
+            package_name = target[JsInfo].npm_package_store_infos.to_list()[0].package
+        return [NpmPackage(name = package_name)]
+    return []
+
+# Aspect to include the npm package name for use in strict deps checking.
+_npm_package_aspect = aspect(
+    implementation = _npm_package_aspect_impl,
+    required_providers = [],
+)
+
+def _strict_deps_impl(ctx):
+    sources = []
+
+    allowed_sources = []
+    allowed_module_names = []
+    test_files = []
+
+    # Whether or not the strict_deps check is expected to fail.
+    expect_failure = "true" if ctx.attr.will_fail else "false"
+
+    for dep in ctx.attr.deps:
+        if JsInfo in dep:
+            # Because each source maps to a corresponding type file, we can simply look at the type
+            # files for the sources, this also allows for situations in which we only provide types.
+            sources.append(dep[JsInfo].types)
+        if NpmPackage in dep:
+            allowed_module_names.append(dep[NpmPackage].name)
+
+    for source in depset(transitive = sources).to_list():
+        allowed_sources.append(source.short_path)
+
+    for file in ctx.files.srcs:
+        allowed_sources.append(file.short_path)
+        if file.is_source:
+            test_files.append(file.short_path)
+
+    manifest = ctx.actions.declare_file("%s_strict_deps_manifest.json" % ctx.attr.name)
+    ctx.actions.write(
+        output = manifest,
+        content = json.encode({
+            # Note: Ensure this matches `StrictDepsManifest` from `manifest.mts`
+            "testFiles": test_files,
+            "allowedModuleNames": allowed_module_names,
+            "allowedSources": allowed_sources,
+        }),
+    )
+
+    launcher = ctx.actions.declare_file("%s_launcher.sh" % ctx.attr.name)
+    ctx.actions.write(
+        output = launcher,
+        is_executable = True,
+        # Bash runfile library taken from:
+        # https://github.com/bazelbuild/bazel/blob/master/tools/bash/runfiles/runfiles.bash.
+        content = """
+            #!/usr/bin/env bash
+
+            # --- begin runfiles.bash initialization v3 ---
+            # Copy-pasted from the Bazel Bash runfiles library v3.
+            set -uo pipefail; set +e; f=bazel_tools/tools/bash/runfiles/runfiles.bash
+            # shellcheck disable=SC1090
+            source "${RUNFILES_DIR:-/dev/null}/$f" 2>/dev/null || \
+            source "$(grep -sm1 "^$f " "${RUNFILES_MANIFEST_FILE:-/dev/null}" | cut -f2- -d' ')" 2>/dev/null || \
+            source "$0.runfiles/$f" 2>/dev/null || \
+            source "$(grep -sm1 "^$f " "$0.runfiles_manifest" | cut -f2- -d' ')" 2>/dev/null || \
+            source "$(grep -sm1 "^$f " "$0.exe.runfiles_manifest" | cut -f2- -d' ')" 2>/dev/null || \
+            { echo>&2 "ERROR: cannot find $f"; exit 1; }; f=; set -e
+            # --- end runfiles.bash initialization v3 ---
+
+            exec $(rlocation %s) $(rlocation %s) %s
+        """ % (
+            "%s/%s" % (ctx.workspace_name, ctx.files._bin[0].short_path),
+            "%s/%s" % (ctx.workspace_name, manifest.short_path),
+            expect_failure,
+        ),
+    )
+
+    bin_runfiles = ctx.attr._bin[DefaultInfo].default_runfiles
+
+    return [
+        DefaultInfo(
+            executable = launcher,
+            runfiles = ctx.runfiles(
+                files = ctx.files._runfiles_lib + ctx.files.srcs + [manifest],
+            ).merge(bin_runfiles),
+        ),
+    ]
+
+_strict_deps_test = rule(
+    implementation = _strict_deps_impl,
+    test = True,
+    doc = "Rule to verify that specified TS files only import from explicitly listed deps.",
+    attrs = {
+        "deps": attr.label_list(
+            aspects = [_npm_package_aspect],
+            doc = "Direct dependencies that are allowed",
+            default = [],
+        ),
+        "srcs": attr.label_list(
+            doc = "TS files to be checked",
+            allow_files = True,
+            mandatory = True,
+        ),
+        "will_fail": attr.bool(
+            doc = "Whether the test is expected to fail",
+            default = False,
+        ),
+        "_runfiles_lib": attr.label(
+            default = "@bazel_tools//tools/bash/runfiles",
+        ),
+        "_bin": attr.label(
+            default = "@devinfra//bazel/ts_project/strict_deps:bin",
+            executable = True,
+            cfg = "exec",
+        ),
+    },
+)
+
+def strict_deps_test(**kwargs):
+    kwargs["will_fail"] = False
+    _strict_deps_test(**kwargs)
+
+def invalid_strict_deps_test(**kwargs):
+    kwargs["will_fail"] = True
+    _strict_deps_test(**kwargs)
diff --git a/bazel/ts_project/strict_deps/index.mts b/bazel/ts_project/strict_deps/index.mts
new file mode 100644
index 000000000..7364b6fc6
--- /dev/null
+++ b/bazel/ts_project/strict_deps/index.mts
@@ -0,0 +1,77 @@
+import fs from 'node:fs/promises';
+import path from 'node:path';
+import ts from 'typescript';
+import {createDiagnostic} from './diagnostic.mjs';
+import {StrictDepsManifest} from './manifest.mjs';
+import {getImportsInSourceFile} from './visitor.mjs';
+
+const [manifestExecPath, expectedFailureRaw] = process.argv.slice(2);
+const expectedFailure = expectedFailureRaw === 'true';
+
+const manifest: StrictDepsManifest = JSON.parse(await fs.readFile(manifestExecPath, 'utf8'));
+
+/**
+ * Regex matcher to extract a npm package name, potentially with scope from a subpackage import path.
+ */
+const moduleSpeciferMatcher = /^(@[\w\d-_]+\/)?([\w\d-_]+)/;
+const extensionRemoveRegex = /\.[mc]?(js|(d\.)?ts)$/;
+const allowedModuleNames = new Set<string>(manifest.allowedModuleNames);
+const allowedSources = new Set<string>(
+  manifest.allowedSources.map((s) => s.replace(extensionRemoveRegex, '')),
+);
+
+const diagnostics: ts.Diagnostic[] = [];
+
+for (const fileExecPath of manifest.testFiles) {
+  const content = await fs.readFile(fileExecPath, 'utf8');
+  const sf = ts.createSourceFile(fileExecPath, content, ts.ScriptTarget.ESNext, true);
+  const imports = getImportsInSourceFile(sf);
+
+  for (const i of imports) {
+    const moduleSpecifier = i.moduleSpecifier.replace(extensionRemoveRegex, '');
+    // When the module specified is the file itself this is always a valid dep.
+    if (i.moduleSpecifier === '') {
+      continue;
+    }
+    if (moduleSpecifier.startsWith('.')) {
+      const targetFilePath = path.posix.join(
+        path.dirname(i.diagnosticNode.getSourceFile().fileName),
+        moduleSpecifier,
+      );
+
+      if (allowedSources.has(targetFilePath) || allowedSources.has(`${targetFilePath}/index`)) {
+        continue;
+      }
+    }
+
+    if (moduleSpecifier.startsWith('node:') && allowedModuleNames.has('@types/node')) {
+      continue;
+    }
+
+    if (
+      allowedModuleNames.has(moduleSpecifier.match(moduleSpeciferMatcher)?.[0] || moduleSpecifier)
+    ) {
+      continue;
+    }
+
+    diagnostics.push(
+      createDiagnostic(`No explicit Bazel dependency for this module.`, i.diagnosticNode),
+    );
+  }
+}
+
+if (diagnostics.length > 0) {
+  const formattedDiagnostics = ts.formatDiagnosticsWithColorAndContext(diagnostics, {
+    getCanonicalFileName: (f) => f,
+    getCurrentDirectory: () => '',
+    getNewLine: () => '\n',
+  });
+  console.error(formattedDiagnostics);
+  process.exitCode = 1;
+}
+
+if (expectedFailure && process.exitCode !== 0) {
+  console.log('Strict deps testing was marked as expected to fail, marking test as passing.');
+  // Force the exit code back to 0 as the process was expected to fail.
+  process.exitCode = 0;
+}
diff --git a/bazel/ts_project/strict_deps/manifest.mts b/bazel/ts_project/strict_deps/manifest.mts
new file mode 100644
index 000000000..ab547c130
--- /dev/null
+++ b/bazel/ts_project/strict_deps/manifest.mts
@@ -0,0 +1,5 @@
+export interface StrictDepsManifest {
+  allowedModuleNames: string[];
+  allowedSources: string[];
+  testFiles: string[];
+}
diff --git a/bazel/ts_project/strict_deps/test/BUILD.bazel b/bazel/ts_project/strict_deps/test/BUILD.bazel
new file mode 100644
index 000000000..d4f3d7d2e
--- /dev/null
+++ b/bazel/ts_project/strict_deps/test/BUILD.bazel
@@ -0,0 +1,56 @@
+load("@aspect_rules_ts//ts:defs.bzl", "ts_project")
+load("//bazel/ts_project/strict_deps:index.bzl", "invalid_strict_deps_test", "strict_deps_test")
+
+ts_project(
+    name = "sibling_import_from_depth",
+    srcs = ["sibling_import_from_depth.ts"],
+    deps = [
+        "//bazel/ts_project/strict_deps/test/depth",
+    ],
+)
+
+strict_deps_test(
+    name = "import_node_module",
+    srcs = ["import_node_module.ts"],
+    deps = [
+        "//bazel:node_modules/@types/node",
+    ],
+)
+
+invalid_strict_deps_test(
+    name = "invalid_import_node_module",
+    srcs = ["import_node_module.ts"],
+)
+
+strict_deps_test(
+    name = "import_npm_module",
+    srcs = ["import_npm_module.ts"],
+    deps = ["//bazel:node_modules/@microsoft/api-extractor"],
+)
+
+invalid_strict_deps_test(
+    name = "invalid_import_npm_module_transitively",
+    srcs = ["import_npm_module.ts"],
+    deps = [
+        "//bazel/ts_project/strict_deps/test/import_npm_module",
+    ],
+)
+
+invalid_strict_deps_test(
+    name = "invalid_import_npm_module",
+    srcs = ["import_npm_module.ts"],
+)
+
+strict_deps_test(
+    name = "import_from_depth",
+    srcs = ["import_from_depth.ts"],
+    deps = ["//bazel/ts_project/strict_deps/test/depth"],
+)
+
+invalid_strict_deps_test(
+    name = "invalid_import_from_depth",
+    srcs = ["import_from_depth.ts"],
+    deps = [
+        ":sibling_import_from_depth",
+    ],
+)
diff --git a/bazel/ts_project/strict_deps/test/depth/BUILD.bazel b/bazel/ts_project/strict_deps/test/depth/BUILD.bazel
new file mode 100644
index 000000000..dc7818df9
--- /dev/null
+++ b/bazel/ts_project/strict_deps/test/depth/BUILD.bazel
@@ -0,0 +1,8 @@
+load("@aspect_rules_ts//ts:defs.bzl", "ts_project")
+
+ts_project(
+    name = "depth",
+    srcs = ["file.ts"],
+    declaration = True,
+    visibility = ["//visibility:public"],
+)
diff --git a/bazel/ts_project/strict_deps/test/depth/file.ts b/bazel/ts_project/strict_deps/test/depth/file.ts
new file mode 100644
index 000000000..cd2dcde1e
--- /dev/null
+++ b/bazel/ts_project/strict_deps/test/depth/file.ts
@@ -0,0 +1 @@
+export const depthValue = 42;
diff --git a/bazel/ts_project/strict_deps/test/depth/tsconfig.json b/bazel/ts_project/strict_deps/test/depth/tsconfig.json
new file mode 100644
index 000000000..94205b059
--- /dev/null
+++ b/bazel/ts_project/strict_deps/test/depth/tsconfig.json
@@ -0,0 +1,7 @@
+{
+  "compilerOptions": {
+    "strict": true,
+    "lib": ["esnext", "DOM"],
+    "declaration": true
+  }
+}
diff --git a/bazel/ts_project/strict_deps/test/import_from_depth.ts b/bazel/ts_project/strict_deps/test/import_from_depth.ts
new file mode 100644
index 000000000..2a3affeca
--- /dev/null
+++ b/bazel/ts_project/strict_deps/test/import_from_depth.ts
@@ -0,0 +1,3 @@
+import {depthValue} from './depth/file';
+
+console.log(`The value from deeper down is ${depthValue}`);
diff --git a/bazel/ts_project/strict_deps/test/import_node_module.ts b/bazel/ts_project/strict_deps/test/import_node_module.ts
new file mode 100644
index 000000000..12ff64316
--- /dev/null
+++ b/bazel/ts_project/strict_deps/test/import_node_module.ts
@@ -0,0 +1,4 @@
+import {basename, join} from 'node:path';
+import {cwd} from 'node:process';
+
+join(basename(cwd()), 'test.txt');
diff --git a/bazel/ts_project/strict_deps/test/import_npm_module.ts b/bazel/ts_project/strict_deps/test/import_npm_module.ts
new file mode 100644
index 000000000..b349d2182
--- /dev/null
+++ b/bazel/ts_project/strict_deps/test/import_npm_module.ts
@@ -0,0 +1,3 @@
+import {Extractor} from '@microsoft/api-extractor';
+
+export const AnExtractor = Extractor;
diff --git a/bazel/ts_project/strict_deps/test/import_npm_module/BUILD.bazel b/bazel/ts_project/strict_deps/test/import_npm_module/BUILD.bazel
new file mode 100644
index 000000000..911045acd
--- /dev/null
+++ b/bazel/ts_project/strict_deps/test/import_npm_module/BUILD.bazel
@@ -0,0 +1,10 @@
+load("@aspect_rules_ts//ts:defs.bzl", "ts_project")
+
+ts_project(
+    name = "import_npm_module",
+    srcs = ["index.ts"],
+    visibility = ["//visibility:public"],
+    deps = [
+        "//bazel:node_modules/@microsoft/api-extractor",
+    ],
+)
diff --git a/bazel/ts_project/strict_deps/test/import_npm_module/index.ts b/bazel/ts_project/strict_deps/test/import_npm_module/index.ts
new file mode 100644
index 000000000..36fe84eb4
--- /dev/null
+++ b/bazel/ts_project/strict_deps/test/import_npm_module/index.ts
@@ -0,0 +1,3 @@
+import {Extractor} from '@microsoft/api-extractor';
+
+console.log(Extractor);
diff --git a/bazel/ts_project/strict_deps/test/import_npm_module/tsconfig.json b/bazel/ts_project/strict_deps/test/import_npm_module/tsconfig.json
new file mode 100644
index 000000000..93c008b62
--- /dev/null
+++ b/bazel/ts_project/strict_deps/test/import_npm_module/tsconfig.json
@@ -0,0 +1,6 @@
+{
+  "compilerOptions": {
+    "strict": true,
+    "lib": ["esnext", "DOM"]
+  }
+}
diff --git a/bazel/ts_project/strict_deps/test/sibling_import_from_depth.ts b/bazel/ts_project/strict_deps/test/sibling_import_from_depth.ts
new file mode 100644
index 000000000..0b0baacdd
--- /dev/null
+++ b/bazel/ts_project/strict_deps/test/sibling_import_from_depth.ts
@@ -0,0 +1,3 @@
+import {depthValue} from './depth/file';
+
+console.log(depthValue);
diff --git a/bazel/ts_project/strict_deps/test/transitive_from_depth.ts b/bazel/ts_project/strict_deps/test/transitive_from_depth.ts
new file mode 100644
index 000000000..e80e6e247
--- /dev/null
+++ b/bazel/ts_project/strict_deps/test/transitive_from_depth.ts
@@ -0,0 +1 @@
+export {depthValue} from './depth/file';
diff --git a/bazel/ts_project/strict_deps/test/tsconfig.json b/bazel/ts_project/strict_deps/test/tsconfig.json
new file mode 100644
index 000000000..93c008b62
--- /dev/null
+++ b/bazel/ts_project/strict_deps/test/tsconfig.json
@@ -0,0 +1,6 @@
+{
+  "compilerOptions": {
+    "strict": true,
+    "lib": ["esnext", "DOM"]
+  }
+}
diff --git a/bazel/ts_project/strict_deps/tsconfig.json b/bazel/ts_project/strict_deps/tsconfig.json
new file mode 100644
index 000000000..c553a5d72
--- /dev/null
+++ b/bazel/ts_project/strict_deps/tsconfig.json
@@ -0,0 +1,9 @@
+{
+  "compilerOptions": {
+    "strict": true,
+    "module": "NodeNext",
+    "moduleResolution": "nodenext",
+    "types": ["node"]
+  },
+  "files": ["index.mts"]
+}
diff --git a/bazel/ts_project/strict_deps/visitor.mts b/bazel/ts_project/strict_deps/visitor.mts
new file mode 100644
index 000000000..deeaeddd7
--- /dev/null
+++ b/bazel/ts_project/strict_deps/visitor.mts
@@ -0,0 +1,40 @@
+import ts from 'typescript';
+
+export interface Import {
+  diagnosticNode: ts.Node;
+  moduleSpecifier: string;
+}
+
+export function getImportsInSourceFile(sf: ts.SourceFile): Import[] {
+  const result: Import[] = [];
+
+  const visitor = (node: ts.Node) => {
+    if (ts.isImportDeclaration(node) || ts.isExportDeclaration(node)) {
+      const moduleSpecifier = node.moduleSpecifier as ts.StringLiteral;
+      // If not moduleSpecifier is included in the declaration, it is infered to be the local file,
+      // essentially a self import and can be ignored.
+      if (moduleSpecifier) {
+        result.push({
+          diagnosticNode: moduleSpecifier,
+          moduleSpecifier: moduleSpecifier.text,
+        });
+      }
+    }
+    if (
+      ts.isCallExpression(node) &&
+      node.expression.kind === ts.SyntaxKind.ImportKeyword &&
+      node.arguments.length >= 1 &&
+      ts.isStringLiteralLike(node.arguments[0])
+    ) {
+      result.push({
+        diagnosticNode: node,
+        moduleSpecifier: node.arguments[0].text,
+      });
+    }
+    ts.forEachChild(node, visitor);
+  };
+
+  ts.forEachChild(sf, visitor);
+
+  return result;
+}