fix(pipeline): harden ADR preservation and add regression test (#516)

Addresses review on #539.

- Free p->saved_adr in cbm_pipeline_free so it is not leaked on error
  paths that exit before the restore in dump_and_persist_hashes (e.g. a
  cbm_gbuf_dump_to_sqlite failure).
- Check cbm_store_adr_store's return value on restore and log an error
  instead of silently dropping the ADR (the original #516 symptom).
- Add reproduce-first test pipeline_adr_survives_full_reindex: index,
  store an ADR, force a full re-index by adding files, assert the ADR
  survives unchanged. Passes against the fix.

Signed-off-by: RithvikReddy0-0 <rithvikreddymukkara@gmail.com>

Author: RithvikReddy0-0

src/pipeline/pipeline.c

@@ -186,6 +186,9 @@ void cbm_pipeline_free(cbm_pipeline_t *p) {
     p->excluded_dirs = NULL;
     p->excluded_count = 0;
     free(p->branch_qn);
+    free(p->saved_adr); /* freed here too: error paths can exit before the
+                         * restore in dump_and_persist_hashes runs. Issue #516. */
+    p->saved_adr = NULL;
     cbm_git_context_free(&p->git_ctx);
     /* gbuf, store, registry freed during/after run */
     /* Defensively free userconfig in case run() was never called or panicked */
@@ -890,9 +893,12 @@ static int dump_and_persist_hashes(cbm_pipeline_t *p, const cbm_file_info_t *fil
     if (hash_store) {
         cbm_store_delete_file_hashes(hash_store, p->project_name);
 
-        /* Restore the ADR captured before the dump. Issue #516. */
+        /* Restore the ADR captured before the dump. Surface a failed restore
+         * rather than silently dropping the ADR (the original #516 symptom). */
         if (p->saved_adr) {
-            cbm_store_adr_store(hash_store, p->project_name, p->saved_adr);
+            if (cbm_store_adr_store(hash_store, p->project_name, p->saved_adr) != CBM_STORE_OK) {
+                cbm_log_error("pipeline.err", "phase", "adr_restore", "project", p->project_name);
+            }
         }
         for (int i = 0; i < file_count; i++) {
             struct stat fst;

tests/test_pipeline.c

@@ -273,6 +273,75 @@ TEST(pipeline_structure_nodes) {
     PASS();
 }
 
+/* Issue #516: an ADR stored via manage_adr (project_summaries) must survive a
+ * full re-index. A full re-index deletes the DB and rebuilds it from the graph
+ * buffer, which writes an empty project_summaries table; the fix captures the
+ * ADR before the delete and restores it after the rebuild. Reproduce-first:
+ * index, store an ADR, force a full re-index by adding files, assert the ADR
+ * is still present and unchanged. */
+TEST(pipeline_adr_survives_full_reindex) {
+    char tmp[256];
+    snprintf(tmp, sizeof(tmp), "/tmp/cbm_adr_XXXXXX");
+    if (!cbm_mkdtemp(tmp)) {
+        FAIL("failed to create temp dir");
+    }
+
+    char db_path[512];
+    snprintf(db_path, sizeof(db_path), "%s/test.db", tmp);
+
+    /* Initial index with a single source file. */
+    char path[512];
+    snprintf(path, sizeof(path), "%s/main.py", tmp);
+    FILE *f = fopen(path, "w");
+    ASSERT_NOT_NULL(f);
+    fprintf(f, "def foo():\n    pass\n");
+    fclose(f);
+
+    cbm_pipeline_t *p1 = cbm_pipeline_new(tmp, db_path, CBM_MODE_FULL);
+    ASSERT_NOT_NULL(p1);
+    ASSERT_EQ(cbm_pipeline_run(p1), 0);
+    const char *project = cbm_pipeline_project_name(p1);
+    char project_copy[256];
+    snprintf(project_copy, sizeof(project_copy), "%s", project);
+    cbm_pipeline_free(p1);
+
+    /* Store an ADR. */
+    const char *adr_text = "# Decision\nWe chose X over Y.";
+    cbm_store_t *s1 = cbm_store_open_path(db_path);
+    ASSERT_NOT_NULL(s1);
+    ASSERT_EQ(cbm_store_adr_store(s1, project_copy, adr_text), CBM_STORE_OK);
+    cbm_store_close(s1);
+
+    /* Force a full re-index: add enough files to exceed the incremental
+     * threshold so the DB is deleted and rebuilt. */
+    for (int i = 0; i < 4; i++) {
+        snprintf(path, sizeof(path), "%s/extra%d.py", tmp, i);
+        f = fopen(path, "w");
+        ASSERT_NOT_NULL(f);
+        fprintf(f, "def g%d():\n    return %d\n", i, i);
+        fclose(f);
+    }
+
+    cbm_pipeline_t *p2 = cbm_pipeline_new(tmp, db_path, CBM_MODE_FULL);
+    ASSERT_NOT_NULL(p2);
+    ASSERT_EQ(cbm_pipeline_run(p2), 0);
+    cbm_pipeline_free(p2);
+
+    /* The ADR must still be present and unchanged. */
+    cbm_store_t *s2 = cbm_store_open_path(db_path);
+    ASSERT_NOT_NULL(s2);
+    cbm_adr_t adr = {0};
+    int rc = cbm_store_adr_get(s2, project_copy, &adr);
+    ASSERT_EQ(rc, CBM_STORE_OK);
+    ASSERT_NOT_NULL(adr.content);
+    ASSERT_STR_EQ(adr.content, adr_text);
+    cbm_store_adr_free(&adr);
+    cbm_store_close(s2);
+
+    rm_rf(tmp);
+    PASS();
+}
+
 TEST(pipeline_structure_edges) {
     if (setup_test_repo() != 0) {
         FAIL("failed to create temp dir");
@@ -6092,6 +6161,7 @@ SUITE(pipeline) {
     /* Integration: structure pass */
     RUN_TEST(pipeline_structure_nodes);
     RUN_TEST(pipeline_committed_counts_match_persisted);
+    RUN_TEST(pipeline_adr_survives_full_reindex);
     RUN_TEST(pipeline_structure_edges);
     RUN_TEST(pipeline_branch_root_structure);
     RUN_TEST(pipeline_project_name_derived);