fix(elixir): functions carry no complexity, fingerprint or line count

internal/cbm/extract_defs.c

@@ -4985,6 +4985,134 @@ static TSNode elixir_call_args(TSNode node) {
 }
 
 // Handle Elixir def/defp/defmacro — extract function definition.
+/* True when node `n` spans exactly the text `lit`. Avoids an arena allocation
+ * per node in the complexity walk, which visits every node of every def. */
+static bool elixir_node_text_is(TSNode n, const char *source, const char *lit) {
+    if (ts_node_is_null(n)) {
+        return false;
+    }
+    uint32_t s = ts_node_start_byte(n);
+    uint32_t e = ts_node_end_byte(n);
+    size_t len = strlen(lit);
+    return (size_t)(e - s) == len && strncmp(source + s, lit, len) == 0;
+}
+
+/* Elixir has no branching NODE TYPES. `if`, `unless`, `case`, `cond`, `with`,
+ * `for`, `try` and `receive` are ordinary `call` nodes told apart only by the
+ * identifier in callee position, and every case/cond/fn/rescue arm is a
+ * `stab_clause`. lang_specs.c cannot express that — the Elixir branch table is
+ * `{"call"}`, which would score every function call as a decision — and
+ * cbm_compute_complexity matches on node type, so the generic path is unusable
+ * and every Elixir function shipped complexity 0.
+ *
+ * Counted here: the branching construct itself, every `stab_clause`, the
+ * short-circuit operators, and `when` guards. Container AND arm are both
+ * counted, which is the convention the generic tables already use — Go counts
+ * `expression_switch_statement` plus each `expression_case`, Python counts
+ * `try_statement` plus each `except_clause`. Cognitive weighting is Campbell's,
+ * identical to the generic walk (+1 plus the current nesting depth). */
+static bool elixir_is_branch_call(TSNode call, const char *source) {
+    if (ts_node_child_count(call) == 0) {
+        return false;
+    }
+    TSNode callee = ts_node_child(call, 0);
+    if (ts_node_is_null(callee) || strcmp(ts_node_type(callee), "identifier") != 0) {
+        return false;
+    }
+    return elixir_node_text_is(callee, source, "if") ||
+           elixir_node_text_is(callee, source, "unless") ||
+           elixir_node_text_is(callee, source, "with") ||
+           elixir_node_text_is(callee, source, "for") ||
+           elixir_node_text_is(callee, source, "case") ||
+           elixir_node_text_is(callee, source, "cond") ||
+           elixir_node_text_is(callee, source, "try") ||
+           elixir_node_text_is(callee, source, "receive");
+}
+
+/* A comprehension (`for x <- xs, do: ...`) is Elixir's only real loop node.
+ * Enum.map/reduce iterate too, but they are plain function calls; counting them
+ * would make loop_depth meaningless, so they are left out. */
+static bool elixir_is_loop_call(TSNode call, const char *source) {
+    if (ts_node_child_count(call) == 0) {
+        return false;
+    }
+    TSNode callee = ts_node_child(call, 0);
+    return !ts_node_is_null(callee) && strcmp(ts_node_type(callee), "identifier") == 0 &&
+           elixir_node_text_is(callee, source, "for");
+}
+
+static bool elixir_is_branch_operator(TSNode node, const char *source) {
+    TSNode op = ts_node_child_by_field_name(node, TS_FIELD("operator"));
+    return elixir_node_text_is(op, source, "&&") || elixir_node_text_is(op, source, "||") ||
+           elixir_node_text_is(op, source, "and") || elixir_node_text_is(op, source, "or") ||
+           elixir_node_text_is(op, source, "when");
+}
+
+static void elixir_compute_complexity(TSNode node, const char *source, cbm_complexity_t *out) {
+    enum { ELIXIR_CX_STACK_CAP = 4096 };
+    struct {
+        TSNode node;
+        int bdepth;
+        int ldepth;
+        int adepth;
+    } stack[ELIXIR_CX_STACK_CAP];
+    memset(out, 0, sizeof(*out));
+    int top = 0;
+    stack[top].node = node;
+    stack[top].bdepth = 0;
+    stack[top].ldepth = 0;
+    stack[top].adepth = 0;
+    top++;
+    while (top > 0) {
+        int cur = --top;
+        TSNode n = stack[cur].node;
+        int bdepth = stack[cur].bdepth;
+        int ldepth = stack[cur].ldepth;
+        int adepth = stack[cur].adepth;
+        const char *kind = ts_node_type(n);
+        bool is_branch = false;
+        if (strcmp(kind, "stab_clause") == 0) {
+            is_branch = true;
+        } else if (strcmp(kind, "call") == 0) {
+            is_branch = elixir_is_branch_call(n, source);
+        } else if (strcmp(kind, "binary_operator") == 0) {
+            is_branch = elixir_is_branch_operator(n, source);
+        }
+        int child_b = bdepth;
+        int child_l = ldepth;
+        /* `conn.assigns.user` nests as dot(dot(conn)), so consecutive `dot`
+         * nodes deepen the chain and anything else resets it. */
+        int child_a = 0;
+        if (strcmp(kind, "dot") == 0) {
+            child_a = adepth + 1;
+            if (child_a > out->max_access_depth) {
+                out->max_access_depth = child_a;
+            }
+        }
+        if (is_branch) {
+            out->cyclomatic++;
+            out->cognitive += 1 + bdepth;
+            child_b = bdepth + 1;
+        }
+        if (strcmp(kind, "call") == 0 && elixir_is_loop_call(n, source)) {
+            out->loop_count++;
+            int d = ldepth + 1;
+            if (d > out->loop_depth) {
+                out->loop_depth = d;
+            }
+            child_l = d;
+        }
+        uint32_t nc = ts_node_child_count(n);
+        for (int i = (int)nc - 1; i >= 0 && top < ELIXIR_CX_STACK_CAP; i--) {
+            stack[top].node = ts_node_child(n, (uint32_t)i);
+            stack[top].bdepth = child_b;
+            stack[top].ldepth = child_l;
+            stack[top].adepth = child_a;
+            top++;
+        }
+    }
+}
+
 static void extract_elixir_func_def(CBMExtractCtx *ctx, TSNode node, const char *macro) {
     CBMArena *a = ctx->arena;
     TSNode args = elixir_call_args(node);
@@ -5017,6 +5145,21 @@ static void extract_elixir_func_def(CBMExtractCtx *ctx, TSNode node, const char
     def.start_line = ts_node_start_point(node).row + TS_LINE_OFFSET;
     def.end_line = ts_node_end_point(node).row + TS_LINE_OFFSET;
     def.is_exported = (strcmp(macro, "def") == 0 || strcmp(macro, "defmacro") == 0);
+    def.lines = (int)(def.end_line - def.start_line + TS_LINE_OFFSET);
+    cbm_complexity_t cx;
+    elixir_compute_complexity(node, ctx->source, &cx);
+    def.complexity = cx.cyclomatic;
+    def.cognitive = cx.cognitive;
+    def.loop_count = cx.loop_count;
+    def.loop_depth = cx.loop_depth;
+    def.max_access_depth = cx.max_access_depth;
+    /* Fingerprint off the body, not the whole def call: including the head
+     * would make every clause of a name look alike. Elixir was the only
+     * language emitting Functions with no fingerprint at all, so it never
+     * appeared in similarity or duplicate results. Runs after `lines` — the
+     * AST profile reads it. */
+    TSNode fp_body = cbm_find_child_by_kind(node, "do_block");
+    compute_fingerprint(ctx, &def, ts_node_is_null(fp_body) ? node : fp_body);
     cbm_defs_push(&ctx->result->defs, a, def);
 }
 

tests/test_extraction.c

@@ -1005,6 +1005,45 @@ TEST(elixir_function) {
     PASS();
 }
 
+/* Elixir control flow is `call` nodes and `stab_clause` arms, not branch node
+ * TYPES, so the generic complexity walk scored every Elixir function 0 and the
+ * fingerprint was never computed at all — no similarity or duplicate detection. */
+TEST(elixir_complexity_and_fingerprint) {
+    CBMFileResult *r = extract("defmodule Cx do\n"
+                               "  def classify(x) do\n"
+                               "    case x do\n"
+                               "      0 -> :zero\n"
+                               "      n when n > 0 -> :pos\n"
+                               "      _ -> :neg\n"
+                               "    end\n"
+                               "  end\n"
+                               "  def plain(a), do: a\n"
+                               "end\n",
+                               CBM_LANG_ELIXIR, "t", "cx.ex");
+    ASSERT_NOT_NULL(r);
+    ASSERT_FALSE(r->has_error);
+    CBMDefinition *cls = NULL;
+    CBMDefinition *plain = NULL;
+    for (int i = 0; i < r->defs.count; i++) {
+        if (strcmp(r->defs.items[i].name, "classify") == 0)
+            cls = &r->defs.items[i];
+        if (strcmp(r->defs.items[i].name, "plain") == 0)
+            plain = &r->defs.items[i];
+    }
+    ASSERT_NOT_NULL(cls);
+    /* The `case` itself + its 3 arms + the second arm's own `when` guard. */
+    ASSERT_EQ(5, cls->complexity);
+    ASSERT(cls->cognitive > 0);
+    ASSERT(cls->lines > 0);
+    /* A straight-line body has no decisions but still gets a line count — a
+     * language must not become nonzero everywhere just by being measured. */
+    ASSERT_NOT_NULL(plain);
+    ASSERT_EQ(0, plain->complexity);
+    ASSERT(plain->lines > 0);
+    cbm_free_result(r);
+    PASS();
+}
+
 /* --- Haskell --- */
 TEST(haskell_function) {
     CBMFileResult *r = extract("add :: Int -> Int -> Int\nadd x y = x + y\n\nmultiply :: Int -> "
@@ -5432,6 +5471,7 @@ SUITE(extraction) {
 
     /* Functional */
     RUN_TEST(elixir_function);
+    RUN_TEST(elixir_complexity_and_fingerprint);
     RUN_TEST(haskell_function);
     RUN_TEST(ocaml_function);
     RUN_TEST(erlang_function);