fix(workspace): do not follow links in the path-alias config walk

find_alias_files descended into every entry whose is_dir flag was set.
On Windows that flag is also set for a directory junction and a directory
symbolic link, so the tsconfig/jsconfig walk could leave the repository
through a link. Discovery and the incremental walker already skip links
(safe_stat, cbm_path_info_utf8().is_symlink); the alias walk now does the
same on every platform, and skips a child whose metadata cannot be read.

On POSIX the walk already stopped at links because readdir reports them
as DT_LNK rather than DT_DIR; the symbolic-link test pins that contract.
The junction test (cmd.exe mklink /J, no privilege needed) is the case
that changes and is compiled on Windows only.

Signed-off-by: Martin Vogel <martin.vogel.tech@gmail.com>

src/pipeline/path_alias.c

@@ -433,6 +433,15 @@ static void find_alias_files(const char *abs_dir, const char *rel_dir, alias_con
         if (cbm_pipeline_relpath_is_excluded(child_rel, excluded_dirs, excluded_count)) {
             continue;
         }
+        /* A link is not followed, as discovery does not follow one. is_dir is
+         * also true for a junction or a directory symbolic link on Windows,
+         * and either can lead out of the repository. A child whose metadata
+         * cannot be read is skipped the same way. */
+        cbm_path_info_t child_info;
+        if (cbm_path_info_utf8(child_abs, &child_info) != CBM_PATH_INFO_OK ||
+            child_info.is_symlink) {
+            continue;
+        }
         find_alias_files(child_abs, child_rel, out, count, max_count, depth + 1, excluded_dirs,
                          excluded_count);
     }

tests/test_path_alias.c

@@ -9,6 +9,7 @@
 #include "test_framework.h"
 #include "../src/pipeline/path_alias.h"
 #include "../src/foundation/compat.h"
+#include "../src/foundation/compat_fs.h"
 
 #include <stdarg.h>
 #include <stdio.h>
@@ -407,6 +408,148 @@ TEST(path_alias_loader_no_configs) {
     PASS();
 }
 
+/* ── Loader does not follow a linked directory ─────────────────── */
+
+/* The walk must not leave the repository through a link, as discovery does
+ * not. A config in a real subdirectory is collected; one reachable only
+ * through a link to a directory outside the tree is not. */
+TEST(path_alias_loader_skips_linked_directory) {
+#ifdef _WIN32
+    /* symlink() does not exist on Windows, and creating a symbolic link there
+     * needs a privilege an ordinary account (and the CI runner) does not hold.
+     * The Windows shape of this case is a directory junction (cmd.exe mklink
+     * /J), which this file has no cmd.exe fixture for; the junction case is
+     * not covered here. */
+    SKIP_PLATFORM("Windows: symlink() unavailable; links need a privilege");
+#else
+    char tmpl[256];
+    snprintf(tmpl, sizeof(tmpl), "/tmp/cbm_palias_link_XXXXXX");
+    char *root = cbm_mkdtemp(tmpl);
+    ASSERT_NOT_NULL(root);
+    char outside_tmpl[256];
+    snprintf(outside_tmpl, sizeof(outside_tmpl), "/tmp/cbm_palias_outside_XXXXXX");
+    char *outside = cbm_mkdtemp(outside_tmpl);
+    ASSERT_NOT_NULL(outside);
+
+    char sub[512];
+    snprintf(sub, sizeof(sub), "%s/pkg", root);
+    cbm_mkdir(sub);
+
+    char path[512];
+    snprintf(path, sizeof(path), "%s/pkg/tsconfig.json", root);
+    ASSERT_EQ(write_file(path,
+                         "{\n  \"compilerOptions\": {\n    \"paths\": {\n"
+                         "      \"@pkg/*\": [\"./src/*\"]\n    }\n  }\n}\n"),
+              0);
+    snprintf(path, sizeof(path), "%s/tsconfig.json", outside);
+    ASSERT_EQ(write_file(path,
+                         "{\n  \"compilerOptions\": {\n    \"paths\": {\n"
+                         "      \"@out/*\": [\"./src/*\"]\n    }\n  }\n}\n"),
+              0);
+
+    char link[512];
+    snprintf(link, sizeof(link), "%s/linked", root);
+    ASSERT_EQ(symlink(outside, link), 0);
+
+    cbm_path_alias_collection_t *coll = cbm_load_path_aliases(root);
+    ASSERT_NOT_NULL(coll);
+    /* Only the real subdirectory contributes a scope. */
+    ASSERT_EQ(coll->count, 1);
+    ASSERT_STR_EQ(coll->scopes[0].dir_prefix, "pkg");
+    ASSERT_NULL(cbm_path_alias_find_for_file(coll, "linked/src/x.ts"));
+    cbm_path_alias_collection_free(coll);
+
+    unlink(link);
+    snprintf(path, sizeof(path), "%s/pkg/tsconfig.json", root);
+    unlink(path);
+    snprintf(path, sizeof(path), "%s/pkg", root);
+    rmdir(path);
+    rmdir(root);
+    snprintf(path, sizeof(path), "%s/tsconfig.json", outside);
+    unlink(path);
+    rmdir(outside);
+    PASS();
+#endif
+}
+
+#ifdef _WIN32
+/* ── Loader does not follow a directory junction (Windows) ─────── */
+
+/* The Windows shape of the linked-directory case. A junction needs no
+ * privilege (a symbolic link does), and the directory listing reports it
+ * with the directory attribute, so is_dir alone would descend through it.
+ * Compiled out elsewhere: cmd.exe and junctions exist only on Windows, so
+ * this case runs on the Windows leg and nowhere else. */
+TEST(path_alias_loader_skips_junction) {
+    char root_tmpl[512];
+    char outside_tmpl[512];
+    snprintf(root_tmpl, sizeof(root_tmpl), "%s/cbm_palias_junction_XXXXXX", cbm_tmpdir());
+    snprintf(outside_tmpl, sizeof(outside_tmpl), "%s/cbm_palias_outside_XXXXXX", cbm_tmpdir());
+    char *root = cbm_mkdtemp(root_tmpl);
+    ASSERT_NOT_NULL(root);
+    char *outside = cbm_mkdtemp(outside_tmpl);
+    ASSERT_NOT_NULL(outside);
+
+    char sub[600];
+    snprintf(sub, sizeof(sub), "%s/pkg", root);
+    cbm_mkdir(sub);
+
+    char path[700];
+    snprintf(path, sizeof(path), "%s/pkg/tsconfig.json", root);
+    ASSERT_EQ(write_file(path,
+                         "{\n  \"compilerOptions\": {\n    \"paths\": {\n"
+                         "      \"@pkg/*\": [\"./src/*\"]\n    }\n  }\n}\n"),
+              0);
+    snprintf(path, sizeof(path), "%s/tsconfig.json", outside);
+    ASSERT_EQ(write_file(path,
+                         "{\n  \"compilerOptions\": {\n    \"paths\": {\n"
+                         "      \"@out/*\": [\"./src/*\"]\n    }\n  }\n}\n"),
+              0);
+
+    /* cbm_tmpdir() can expose the MSYS spelling C:/msys64/...; cmd's mklink
+     * builtin treats the slash before "msys64" as another option delimiter.
+     * Native backslashes are required only at this cmd.exe fixture boundary. */
+    char junction[600];
+    snprintf(junction, sizeof(junction), "%s/linked", root);
+    char junction_native[sizeof(junction)];
+    char outside_native[sizeof(outside_tmpl)];
+    snprintf(junction_native, sizeof(junction_native), "%s", junction);
+    snprintf(outside_native, sizeof(outside_native), "%s", outside);
+    for (char *cursor = junction_native; *cursor; cursor++) {
+        if (*cursor == '/') {
+            *cursor = '\\';
+        }
+    }
+    for (char *cursor = outside_native; *cursor; cursor++) {
+        if (*cursor == '/') {
+            *cursor = '\\';
+        }
+    }
+    const char *junction_argv[] = {"cmd.exe",       "/d",           "/c", "mklink", "/J",
+                                   junction_native, outside_native, NULL};
+    ASSERT_EQ(cbm_exec_no_shell(junction_argv), 0);
+
+    cbm_path_alias_collection_t *coll = cbm_load_path_aliases(root);
+    ASSERT_NOT_NULL(coll);
+    /* Only the real subdirectory contributes a scope. */
+    ASSERT_EQ(coll->count, 1);
+    ASSERT_STR_EQ(coll->scopes[0].dir_prefix, "pkg");
+    ASSERT_NULL(cbm_path_alias_find_for_file(coll, "linked/src/x.ts"));
+    cbm_path_alias_collection_free(coll);
+
+    /* Removing the junction removes the link, not its target. */
+    cbm_rmdir(junction);
+    snprintf(path, sizeof(path), "%s/pkg/tsconfig.json", root);
+    cbm_unlink(path);
+    cbm_rmdir(sub);
+    cbm_rmdir(root);
+    snprintf(path, sizeof(path), "%s/tsconfig.json", outside);
+    cbm_unlink(path);
+    cbm_rmdir(outside);
+    PASS();
+}
+#endif
+
 void suite_path_alias(void);
 void suite_path_alias(void) {
     RUN_TEST(path_alias_at_wildcard);
@@ -421,4 +564,8 @@ void suite_path_alias(void) {
     RUN_TEST(path_alias_loader_monorepo_dotdot_climb);
     RUN_TEST(path_alias_loader_honors_discovery_exclusions);
     RUN_TEST(path_alias_loader_no_configs);
+    RUN_TEST(path_alias_loader_skips_linked_directory);
+#ifdef _WIN32
+    RUN_TEST(path_alias_loader_skips_junction);
+#endif
 }