fix(extract): YAML walkers grow their stacks instead of capping content

walk_yaml_mapping (dotted key paths, 256 frames) and
scan_yaml_for_infra_bindings (512 nodes) kept their pending nodes in
fixed-size stacks and stopped pushing once full. A mapping with more than
256 nested sibling mappings lost the full key_path of every leaf past the
cap: `k299.url` was only recorded as the shorter path that the walk of a
nested block emits on its own.

The infra Route pass decides on those paths. A `data:` payload block with
300 entries lost `data.svcN.webhook_url` for N >= 256, the payload deny
never saw those values, and 44 of them were minted as infra Route nodes.

Both walkers now start on the same-sized on-stack chunk and grow through
cbm_walk_stack_reserve / cbm_walk_stack_release (#2375). If the stack
cannot grow, the failure is logged as extract.walk_stack_alloc_failed and
the walk stops, instead of truncating silently.

Part of #2388.

Signed-off-by: Gaurav Dubey <gauravdubey0107@gmail.com>

internal/cbm/extract_unified.c

@@ -1663,27 +1663,39 @@ typedef struct {
     TSNode node;
     const char *prefix;
 } yaml_walk_frame_t;
-#define YAML_WALK_STACK_CAP CBM_SZ_256
+/* On-stack first chunk of the key-path walk; wider mappings spill to the heap
+ * through cbm_walk_stack_reserve instead of dropping frames (#2388). */
+#define YAML_WALK_STACK_INLINE CBM_SZ_256
 
-/* Push block_mapping children of a block_node/block_mapping value onto the walk stack. */
-static void push_yaml_block_children(TSNode val, const char *path, yaml_walk_frame_t *stack,
-                                     int *top) {
+/* Push block_mapping children of a block_node/block_mapping value onto the walk
+ * stack, growing it as needed. False when the stack could not grow (logged by
+ * cbm_walk_stack_reserve as extract.walk_stack_alloc_failed). */
+static bool push_yaml_block_children(TSNode val, const char *path, yaml_walk_frame_t **stack,
+                                     int *cap, int *top, const yaml_walk_frame_t *inline_buf) {
     uint32_t vnc = ts_node_named_child_count(val);
-    for (int vi = (int)vnc - SKIP_ONE; vi >= 0 && *top < YAML_WALK_STACK_CAP; vi--) {
+    if (!cbm_walk_stack_reserve((void **)stack, cap, *top + (int)vnc, sizeof(yaml_walk_frame_t),
+                                inline_buf, "yaml_key_paths")) {
+        return false;
+    }
+    for (int vi = (int)vnc - SKIP_ONE; vi >= 0; vi--) {
         TSNode vc = ts_node_named_child(val, (uint32_t)vi);
         const char *vctype = ts_node_type(vc);
         if (strcmp(vctype, "block_mapping") == 0 || strcmp(vctype, "block_mapping_pair") == 0) {
-            stack[(*top)++] = (yaml_walk_frame_t){vc, path};
+            (*stack)[(*top)++] = (yaml_walk_frame_t){vc, path};
         }
     }
+    return true;
 }
 
 static void walk_yaml_mapping(CBMExtractCtx *ctx, TSNode root, const char *root_prefix) {
-    yaml_walk_frame_t stack[YAML_WALK_STACK_CAP];
+    yaml_walk_frame_t inline_stack[YAML_WALK_STACK_INLINE];
+    yaml_walk_frame_t *stack = inline_stack;
+    int cap = YAML_WALK_STACK_INLINE;
     int top = 0;
     stack[top++] = (yaml_walk_frame_t){root, root_prefix};
+    bool grown = true;
 
-    while (top > 0) {
+    while (grown && top > 0) {
         yaml_walk_frame_t frame = stack[--top];
         TSNode node = frame.node;
         const char *prefix = frame.prefix;
@@ -1709,12 +1721,16 @@ static void walk_yaml_mapping(CBMExtractCtx *ctx, TSNode root, const char *root_
             }
             const char *vk = ts_node_type(val);
             if (strcmp(vk, "block_node") == 0 || strcmp(vk, "block_mapping") == 0) {
-                push_yaml_block_children(val, path, stack, &top);
+                grown = push_yaml_block_children(val, path, &stack, &cap, &top, inline_stack);
+                if (!grown) {
+                    break;
+                }
                 continue;
             }
             emit_yaml_leaf_value(ctx, val, path);
         }
     }
+    cbm_walk_stack_release(stack, inline_stack);
 }
 
 /* ── Infrastructure binding extraction ─────────────────────────────
@@ -1873,9 +1889,13 @@ static void scan_mapping_for_bindings(CBMExtractCtx *ctx, TSNode mapping) {
     emit_infra_bindings(ctx, sources, source_keys, n_sources, targets, n_targets);
 }
 
-#define INFRA_SCAN_STACK_CAP CBM_SZ_512
+/* On-stack first chunk of the binding scan; wider subtrees spill to the heap
+ * through cbm_walk_stack_reserve instead of dropping nodes (#2388). */
+#define INFRA_SCAN_STACK_INLINE CBM_SZ_512
 static void scan_yaml_for_infra_bindings(CBMExtractCtx *ctx, TSNode root) {
-    TSNode stack[INFRA_SCAN_STACK_CAP];
+    TSNode inline_stack[INFRA_SCAN_STACK_INLINE];
+    TSNode *stack = inline_stack;
+    int cap = INFRA_SCAN_STACK_INLINE;
     int top = 0;
     stack[top++] = root;
     while (top > 0) {
@@ -1884,10 +1904,15 @@ static void scan_yaml_for_infra_bindings(CBMExtractCtx *ctx, TSNode root) {
             scan_mapping_for_bindings(ctx, node);
         }
         uint32_t nc = ts_node_named_child_count(node);
-        for (int i = (int)nc - SKIP_ONE; i >= 0 && top < INFRA_SCAN_STACK_CAP; i--) {
+        if (!cbm_walk_stack_reserve((void **)&stack, &cap, top + (int)nc, sizeof(TSNode),
+                                    inline_stack, "yaml_infra_bindings")) {
+            break;
+        }
+        for (int i = (int)nc - SKIP_ONE; i >= 0; i--) {
             stack[top++] = ts_node_named_child(node, (uint32_t)i);
         }
     }
+    cbm_walk_stack_release(stack, inline_stack);
 }
 
 /* ── HCL infrastructure binding extraction ───────────────────────────

tests/test_extraction.c

@@ -7229,6 +7229,85 @@ TEST(body_tokens_wide_body_samples_from_the_start) {
     PASS();
 }
 
+/* The YAML walkers kept their pending mappings in fixed-size stacks (256 for
+ * the dotted key-path walk, 512 for the infrastructure-binding scan) and
+ * silently stopped pushing once full (#2388). A root mapping with more nested
+ * sibling mappings than the old cap lost the full dotted key_path of every
+ * leaf past it: `k299.url` was only ever recorded as the bare `url` that the
+ * per-mapping walk of the nested block emits. */
+enum { WIDE_YAML_KEYS = 300, WIDE_YAML_ITEMS = 600 };
+
+static int has_string_ref_path(CBMFileResult *r, const char *key_path, const char *value) {
+    for (int i = 0; i < r->string_refs.count; i++) {
+        const CBMStringRef *s = &r->string_refs.items[i];
+        if (s->key_path && s->value && strcmp(s->key_path, key_path) == 0 &&
+            strcmp(s->value, value) == 0) {
+            return 1;
+        }
+    }
+    return 0;
+}
+
+TEST(yaml_key_paths_wide_mapping_exceed_old_stack_cap) {
+    size_t cap = (size_t)WIDE_YAML_KEYS * 48 + 64;
+    char *src = malloc(cap);
+    ASSERT_NOT_NULL(src);
+    size_t pos = 0;
+    for (int i = 0; i < WIDE_YAML_KEYS; i++) {
+        pos += (size_t)snprintf(src + pos, cap - pos,
+                                "k%d:\n  url: \"https://h%d.example.com/x\"\n", i, i);
+    }
+    CBMFileResult *r = extract(src, CBM_LANG_YAML, "t", "wide.yaml");
+    ASSERT_NOT_NULL(r);
+    ASSERT_FALSE(r->has_error);
+    for (int i = 0; i < WIDE_YAML_KEYS; i++) {
+        char path[32];
+        char value[48];
+        snprintf(path, sizeof(path), "k%d.url", i);
+        snprintf(value, sizeof(value), "https://h%d.example.com/x", i);
+        ASSERT(has_string_ref_path(r, path, value));
+    }
+    cbm_free_result(r);
+    free(src);
+    PASS();
+}
+
+static int has_infra_source(CBMFileResult *r, const char *source, const char *url) {
+    for (int i = 0; i < r->infra_bindings.count; i++) {
+        const CBMInfraBinding *b = &r->infra_bindings.items[i];
+        if (b->source_name && b->target_url && strcmp(b->source_name, source) == 0 &&
+            strcmp(b->target_url, url) == 0) {
+            return 1;
+        }
+    }
+    return 0;
+}
+
+TEST(yaml_infra_bindings_wide_sequence_exceed_old_stack_cap) {
+    size_t cap = (size_t)WIDE_YAML_ITEMS * 64 + 64;
+    char *src = malloc(cap);
+    ASSERT_NOT_NULL(src);
+    size_t pos = 0;
+    for (int i = 0; i < WIDE_YAML_ITEMS; i++) {
+        pos += (size_t)snprintf(src + pos, cap - pos,
+                                "- topic: t%d\n  push_endpoint: \"https://h%d.example.com/p\"\n", i,
+                                i);
+    }
+    CBMFileResult *r = extract(src, CBM_LANG_YAML, "t", "pubsub.yaml");
+    ASSERT_NOT_NULL(r);
+    ASSERT_FALSE(r->has_error);
+    for (int i = 0; i < WIDE_YAML_ITEMS; i++) {
+        char source[16];
+        char url[48];
+        snprintf(source, sizeof(source), "t%d", i);
+        snprintf(url, sizeof(url), "https://h%d.example.com/p", i);
+        ASSERT(has_infra_source(r, source, url));
+    }
+    cbm_free_result(r);
+    free(src);
+    PASS();
+}
+
 /* ═══════════════════════════════════════════════════════════════════
  * Perl call-graph noise (#459 follow-up)
  * ═══════════════════════════════════════════════════════════════════ */
@@ -13483,6 +13562,8 @@ SUITE(extraction) {
     RUN_TEST(complexity_wide_body_exceeds_old_stack_cap);
     RUN_TEST(count_branching_wide_body_exceeds_old_stack_cap);
     RUN_TEST(body_tokens_wide_body_samples_from_the_start);
+    RUN_TEST(yaml_key_paths_wide_mapping_exceed_old_stack_cap);
+    RUN_TEST(yaml_infra_bindings_wide_sequence_exceed_old_stack_cap);
     RUN_TEST(extract_c_ifdef_split_brace_fn_recovered_issue961);
     RUN_TEST(extract_cpp_preproc_signature_gap_issue946);
     RUN_TEST(extract_cpp_preproc_macro_generated_callable_skipped_issue949);

tests/test_lang_contract.c

@@ -1553,6 +1553,39 @@ TEST(contract_edge_infra_routes_from_deploy_configs_still_minted) {
     PASS();
 }
 
+/* #2388: the YAML key-path walk kept its pending mappings in a 256-frame stack
+ * and stopped pushing once full. A `data:` payload block with more nested
+ * entries than that lost the full `data.<entry>.webhook_url` path of every entry
+ * past the cap; only the shorter per-mapping refs survived, the payload deny
+ * never saw them, and each of those values minted an infra Route (44 of 300
+ * here). Every payload value must stay unminted however wide the block is. */
+enum { WIDE_PAYLOAD_ENTRIES = 300 };
+
+TEST(contract_edge_no_infra_routes_from_wide_payload_block_issue2388) {
+    size_t cap = (size_t)WIDE_PAYLOAD_ENTRIES * 64 + 16;
+    char *src = malloc(cap);
+    ASSERT_NOT_NULL(src);
+    size_t pos = (size_t)snprintf(src, cap, "data:\n");
+    for (int i = 0; i < WIDE_PAYLOAD_ENTRIES; i++) {
+        pos +=
+            (size_t)snprintf(src + pos, cap - pos,
+                             "  svc%d:\n    webhook_url: https://h%d.payload.example/hook\n", i, i);
+    }
+    LangProj lp;
+    LangFile f[] = {{"service.yaml", src}};
+    cbm_store_t *store = lang_index_files(&lp, f, 1);
+    ASSERT_NOT_NULL(store);
+    int routes = count_infra_routes_matching(store, lp.project, "payload.example");
+    if (routes != 0) {
+        fprintf(stderr, "  [2388] FAIL wide payload block minted %d infra routes (expected 0)\n",
+                routes);
+    }
+    ASSERT_EQ(routes, 0);
+    lang_cleanup(&lp, store);
+    free(src);
+    PASS();
+}
+
 /* A config URL becomes an infra Route only under a key that names an endpoint
  * this service exposes. Reference links are not: across 17 infra repositories
  * the infra Routes were changelog `pull_request` links (deckhouse 6,240),
@@ -1945,6 +1978,7 @@ SUITE(lang_contract) {
     RUN_TEST(contract_edge_python_aliased_import_call_resolves_issue988);
     RUN_TEST(contract_edge_no_infra_routes_from_ci_configs_issue999);
     RUN_TEST(contract_edge_infra_routes_from_deploy_configs_still_minted);
+    RUN_TEST(contract_edge_no_infra_routes_from_wide_payload_block_issue2388);
     RUN_TEST(contract_edge_no_infra_routes_from_reference_links);
     RUN_TEST(contract_edge_infra_routes_from_endpoint_key_spellings);
     RUN_TEST(contract_edge_commonjs_require_call_resolves_issue871);