fix(artifact): write and detect artifacts through wide paths on Windows (#1171)

src/pipeline/artifact.c

@@ -185,7 +185,10 @@ static int write_file_atomic(const char *path, const char *data, size_t len,
         return CBM_NOT_FOUND;
     }
 
-    FILE *fp = fopen(tmp, "wb");
+    /* cbm_fopen / cbm_rename_replace: wide paths on Windows. The ANSI CRT fopen
+     * and MoveFileExA mangled a repo path outside the active code page (a CJK
+     * checkout), so every persistent export failed there (#1171). */
+    FILE *fp = cbm_fopen(tmp, "wb");
     if (!fp) {
         file_error_set(out_err, "open_temp", errno);
         return CBM_NOT_FOUND;
@@ -207,22 +210,14 @@ static int write_file_atomic(const char *path, const char *data, size_t len,
         return CBM_NOT_FOUND;
     }
 
-#ifdef _WIN32
-    /* MoveFileEx replace approach suggested by @Ayush7Ranjan in #492. */
-    if (!MoveFileExA(tmp, path, MOVEFILE_REPLACE_EXISTING | MOVEFILE_WRITE_THROUGH)) {
-        DWORD saved_error = GetLastError();
-        cbm_unlink(tmp);
-        file_error_set(out_err, "rename_temp", (int)saved_error);
-        return CBM_NOT_FOUND;
-    }
-#else
-    if (rename(tmp, path) != 0) {
+    /* Replace-existing rename (MoveFileExW write-through on Windows, the
+     * approach suggested by @Ayush7Ranjan in #492); errno carries the cause. */
+    if (cbm_rename_replace(tmp, path) != 0) {
         int saved_errno = errno;
         cbm_unlink(tmp);
         file_error_set(out_err, "rename_temp", saved_errno);
         return CBM_NOT_FOUND;
     }
-#endif
     return 0;
 }
 
@@ -777,30 +772,31 @@ static void ensure_gitattributes(const char *repo_path) {
     char ga_path[CBM_SZ_4K];
     artifact_path(ga_path, sizeof(ga_path), repo_path, ".gitattributes");
 
-    /* Atomic create-only-if-absent: O_EXCL closes the TOCTOU window
-     * between checking existence and writing. If the file exists, open
-     * fails with EEXIST and we leave it untouched. */
-    int fd = open(ga_path, O_WRONLY | O_CREAT | O_EXCL, 0644);
-    if (fd < 0) {
-        if (errno != EEXIST) {
-            cbm_log_warn("artifact.gitattributes.open path=%s err=%s", ga_path, strerror(errno));
+    /* Atomic create-only-if-absent: the "x" mode (O_CREAT|O_EXCL) closes the
+     * TOCTOU window between checking existence and writing. If the file
+     * exists, the open fails with EEXIST and we leave it untouched.
+     * cbm_fopen, not open(): the ANSI CRT open() cannot create the file under
+     * a repo path outside the active code page on Windows, which silently
+     * dropped the merge=ours protection there (#1171). */
+    errno = 0;
+    FILE *fp = cbm_fopen(ga_path, "wbx");
+    if (!fp) {
+        int open_errno = errno;
+        if (open_errno != EEXIST) {
+            cbm_log_warn("artifact.gitattributes.open", "path", ga_path, "err",
+                         strerror(open_errno));
         }
         /* fall through to merge driver setup either way */
     } else {
-        FILE *fp = fdopen(fd, "w");
-        if (fp) {
-            /* Order matters: attributes apply left to right and the `binary`
-             * macro expands to `-diff -merge -text`, so a trailing `binary`
-             * unsets `merge=ours` and the conflict prevention this file
-             * exists for never engages. The macro must come first. */
-            (void)fputs("# Auto-generated by codebase-memory-mcp\n"
-                        "# Prevent merge conflicts on compressed artifact\n" CBM_ARTIFACT_FILENAME
-                        " binary merge=ours\n",
-                        fp);
-            (void)fclose(fp);
-        } else {
-            (void)close(fd);
-        }
+        /* Order matters: attributes apply left to right and the `binary`
+         * macro expands to `-diff -merge -text`, so a trailing `binary`
+         * unsets `merge=ours` and the conflict prevention this file
+         * exists for never engages. The macro must come first. */
+        (void)fputs("# Auto-generated by codebase-memory-mcp\n"
+                    "# Prevent merge conflicts on compressed artifact\n" CBM_ARTIFACT_FILENAME
+                    " binary merge=ours\n",
+                    fp);
+        (void)fclose(fp);
     }
 
     /* Best-effort: configure merge driver */
@@ -1188,7 +1184,7 @@ int cbm_artifact_import(const char *repo_path, const char *cache_db_path) {
      * stale WAL next to the cache path would be replayed on top of the
      * imported file at the next open (#897). */
     cbm_remove_db_sidecars(cache_db_path);
-    if (rename(tmp_path, cache_db_path) != 0) {
+    if (cbm_rename_replace(tmp_path, cache_db_path) != 0) {
         cbm_log_error("artifact.import", "err", "rename_to_cache");
         cbm_unlink(tmp_path);
         return CBM_NOT_FOUND;
@@ -1218,8 +1214,15 @@ bool cbm_artifact_exists(const char *repo_path) {
     char zst_path[CBM_SZ_4K];
     artifact_path(zst_path, sizeof(zst_path), repo_path, CBM_ARTIFACT_FILENAME);
 
-    struct stat st;
-    if (stat(zst_path, &st) != 0 || st.st_size == 0) {
+    /* Present and non-empty. cbm_fopen, not stat(): the ANSI CRT stat misses a
+     * repo path outside the active Windows code page (#1171). */
+    FILE *fp = cbm_fopen(zst_path, "rb");
+    if (!fp) {
+        return false;
+    }
+    int first = fgetc(fp);
+    (void)fclose(fp);
+    if (first == EOF) {
         return false;
     }
 

tests/test_artifact.c

@@ -334,6 +334,82 @@ TEST(artifact_gitattributes_created) {
     PASS();
 }
 
+/* Read a small file through the UTF-8 path layer (wide on Windows), so a
+ * non-ASCII path is never misread by the test's own ANSI CRT call. Returns the
+ * byte count, or 0 when the file cannot be opened or is empty. */
+static size_t read_small_file_utf8(const char *path, char *buf, size_t cap) {
+    buf[0] = '\0';
+    FILE *fp = cbm_fopen(path, "rb");
+    if (!fp) {
+        return 0;
+    }
+    size_t rd = fread(buf, 1, cap - 1, fp);
+    (void)fclose(fp);
+    buf[rd] = '\0';
+    return rd;
+}
+
+/* #1171: a repository (and a cache directory) under a non-ASCII path must
+ * export, report the artifact present, and import — also onto an existing
+ * cache db. On Windows the atomic writer used the ANSI CRT fopen + MoveFileExA
+ * and the existence check the ANSI stat, so CJK characters outside the active
+ * code page made every step fail. The same export also writes the
+ * .gitattributes merge=ours protection, which ensure_gitattributes created
+ * with the ANSI CRT open(): on Windows it was silently missing. The bytes are
+ * escaped UTF-8 for a CJK repo directory name and a CJK cache directory name
+ * (kept ASCII in source). */
+#define ART_CJK_REPO "\xe6\x8c\x81\xe4\xb9\x85\xe5\x8c\x96\xe5\xa4\x8d\xe7\x8e\xb0"
+#define ART_CJK_CACHE "\xe5\xaf\xbc\xe5\x85\xa5"
+TEST(artifact_roundtrip_non_ascii_paths) {
+    setup_artifact_test();
+    create_test_db(g_db);
+
+    char repo[1024];
+    snprintf(repo, sizeof(repo), "%s/cbm-" ART_CJK_REPO, g_tmpdir);
+    ASSERT_TRUE(cbm_mkdir_p(repo, 0755));
+
+    ASSERT_EQ(cbm_artifact_export(g_db, repo, "test-proj", CBM_ARTIFACT_FAST), 0);
+    char zst[1024];
+    snprintf(zst, sizeof(zst), "%s/.codebase-memory/graph.db.zst", repo);
+    ASSERT_TRUE(cbm_file_exists(zst));
+    ASSERT_TRUE(cbm_artifact_exists(repo));
+
+    char ga[1024];
+    snprintf(ga, sizeof(ga), "%s/.codebase-memory/.gitattributes", repo);
+    char ga_content[512];
+    ASSERT_TRUE(read_small_file_utf8(ga, ga_content, sizeof(ga_content)) > 0);
+    ASSERT_NOT_NULL(strstr(ga_content, CBM_ARTIFACT_FILENAME " binary merge=ours"));
+
+    /* Create-only-if-absent: a re-export never rewrites an existing
+     * .gitattributes the user may have edited. */
+    static const char user_ga[] = "# user-owned\n";
+    FILE *uga = cbm_fopen(ga, "wb");
+    ASSERT_NOT_NULL(uga);
+    ASSERT_TRUE(fputs(user_ga, uga) >= 0);
+    ASSERT_EQ(fclose(uga), 0);
+    ASSERT_EQ(cbm_artifact_export(g_db, repo, "test-proj", CBM_ARTIFACT_FAST), 0);
+    ASSERT_EQ(read_small_file_utf8(ga, ga_content, sizeof(ga_content)), strlen(user_ga));
+    ASSERT_STR_EQ(ga_content, user_ga);
+
+    char cache_dir[1024];
+    snprintf(cache_dir, sizeof(cache_dir), "%s/" ART_CJK_CACHE, g_tmpdir);
+    ASSERT_TRUE(cbm_mkdir_p(cache_dir, 0755));
+    char import_db[1024];
+    snprintf(import_db, sizeof(import_db), "%s/imported.db", cache_dir);
+    ASSERT_EQ(cbm_artifact_import(repo, import_db), 0);
+    /* Re-import replaces the existing cache db (the second-session path). */
+    ASSERT_EQ(cbm_artifact_import(repo, import_db), 0);
+
+    cbm_store_t *s = cbm_store_open_path(import_db);
+    ASSERT_NOT_NULL(s);
+    ASSERT_EQ(cbm_store_count_nodes(s, "test-proj"), 2);
+    ASSERT_EQ(cbm_store_count_edges(s, "test-proj"), 1);
+    cbm_store_close(s);
+
+    cleanup_dir(g_tmpdir);
+    PASS();
+}
+
 TEST(artifact_export_rename_failure_logs_specific_error) {
     setup_artifact_test();
     create_test_db(g_db);
@@ -1102,6 +1178,7 @@ SUITE(artifact) {
     RUN_TEST(artifact_schema_version_mismatch);
     RUN_TEST(artifact_import_missing);
     RUN_TEST(artifact_gitattributes_created);
+    RUN_TEST(artifact_roundtrip_non_ascii_paths);
     RUN_TEST(artifact_export_rename_failure_logs_specific_error);
     RUN_TEST(pipeline_persistence_export_failure_returns_error);
     RUN_TEST(artifact_import_rejects_size_mismatch);