fix(test-impact): let a build drop the suites only some runners register

src/mcp/test_impact.c

@@ -630,8 +630,11 @@ static void tm_add_runner_suite(tm_scan_t *sc, const tm_tok_t *name, bool perf)
         return;
     }
     m->runner = items;
-    items[m->runner_count++] =
-        (cbm_test_runner_suite_t){.name = copy, .perf = perf, .file = sc->file, .line = name->line};
+    items[m->runner_count++] = (cbm_test_runner_suite_t){.name = copy,
+                                                         .perf = perf,
+                                                         .file = sc->file,
+                                                         .line = name->line,
+                                                         .conditional = sc->conditions > 0};
 }
 
 /* Virtual preset records are immutable. Original configured records are kept
@@ -1407,11 +1410,14 @@ bool cbm_test_model_finish(cbm_test_model_t *m) {
     }
     if (m->runner_count > 1) {
         qsort(m->runner, (size_t)m->runner_count, sizeof(*m->runner), tm_cmp_runner);
-        /* One entry per suite; it is a perf suite when any site says so. */
+        /* One entry per suite; it is a perf suite when any site says so, and
+         * conditional only when every site is. */
         int kept = 0;
         for (int i = 1; i < m->runner_count; i++) {
             if (strcmp(m->runner[kept].name, m->runner[i].name) == 0) {
                 m->runner[kept].perf = m->runner[kept].perf || m->runner[i].perf;
+                m->runner[kept].conditional =
+                    m->runner[kept].conditional && m->runner[i].conditional;
             } else {
                 m->runner[++kept] = m->runner[i];
             }

src/mcp/test_impact.h

@@ -71,6 +71,9 @@ typedef struct {
     bool perf;
     const char *file; /* the runner file that registers it */
     int line;
+    /* Every site registers it under a preprocessor condition: some builds do
+     * not register this suite at all. */
+    bool conditional;
 } cbm_test_runner_suite_t;
 
 typedef struct cbm_test_model cbm_test_model_t;

src/mcp/test_impact_select.c

@@ -290,9 +290,14 @@ cbm_test_selection_t *cbm_test_select(const cbm_test_selection_input_t *input) {
     for (int i = 0; i < input->reach_count; i++)
         if (reach[i].row->changed && !reach[i].registered)
             return sl_full(result, CBM_TEST_SELECT_CHANGED_UNREGISTERED);
-    for (int i = 0; i < runner_count; i++)
+    for (int i = 0; i < runner_count; i++) {
         if (definition_counts[i] != 1 || !registration_counts[i])
             sl_whole(&result->suites[i], CBM_TEST_SELECT_INVENTORY_UNKNOWN);
+        /* After every whole-suite path: a selected suite that some builds do
+         * not register at all may be absent from the runner that executes it. */
+        if ((result->suites[i].whole || result->suites[i].reasons) && runners[i].conditional)
+            sl_whole(&result->suites[i], CBM_TEST_SELECT_CONDITIONAL);
+    }
     /* A later registration can promote an earlier test's suite to whole.
      * Compact cases while the complete, sorted suite table is still present. */
     int used = 0;

tests/test_test_impact.c

@@ -274,6 +274,33 @@ TEST(test_model_marks_what_is_under_a_condition) {
     PASS();
 }
 
+/* A runner registration under a condition means some builds lack the suite.
+ * A suite registered twice is conditional only when every site is. */
+TEST(test_model_marks_runner_suites_registered_under_a_condition) {
+    static const tm_source_t src[] = {{"tests/test_main.c", "int main(void) {\n"
+                                                            "    RUN_SELECTED_SUITE(always);\n"
+                                                            "#if defined(COV) && !defined(_WIN32)\n"
+                                                            "    RUN_SELECTED_SUITE(guarded);\n"
+                                                            "    RUN_SELECTED_SUITE(twice);\n"
+                                                            "#endif\n"
+                                                            "    RUN_SELECTED_SUITE(twice);\n"
+                                                            "    return 0;\n"
+                                                            "}\n"}};
+    cbm_test_model_t *m = model_of(src, 1);
+    ASSERT_NOT_NULL(m);
+    int n = 0;
+    const cbm_test_runner_suite_t *suites = cbm_test_model_runner_suites(m, &n);
+    ASSERT_EQ(n, 3);
+    ASSERT_STR_EQ(suites[0].name, "always");
+    ASSERT_FALSE(suites[0].conditional);
+    ASSERT_STR_EQ(suites[1].name, "guarded");
+    ASSERT_TRUE(suites[1].conditional);
+    ASSERT_STR_EQ(suites[2].name, "twice");
+    ASSERT_FALSE(suites[2].conditional);
+    cbm_test_model_free(m);
+    PASS();
+}
+
 /* Both branches of an #if may open the same block. Counting both braces would
  * leave the scanner one level deep for the rest of the file, and every later
  * test and suite would be missed. */
@@ -1688,6 +1715,92 @@ TEST(test_selection_inventory_ambiguity_and_conditionals_use_whole_suite) {
     PASS();
 }
 
+/* A suite the runner registers only under a preprocessor condition is absent
+ * from some builds, so however it is selected it must carry CONDITIONAL: the
+ * runner that lacks it then tolerates its absence. Its cases and registrations
+ * are unconditional here, so only the runner registration can say so. */
+TEST(test_selection_conditionally_registered_suite_is_conditional_on_every_path) {
+    /* A map covers every function it lists, so the changed one (0) is covered
+     * by the setup of a suite no runner registers: alpha's own rows stay
+     * quiet and each variant reaches alpha by its one path. */
+    static const char *quiet_rows = "alpha:*\tcomplete\t\t1\nalpha:stat\tcomplete\t\t1\n"
+                                    "alpha:cov\tcomplete\t\t1\nalpha:changed\tcomplete\t\t1\n"
+                                    "alpha:quiet\tcomplete\t\t1\nomega:*\tcomplete\t\t0\n";
+    struct {
+        const char *rows;
+        bool admitted;
+        bool reached, changed, rule;
+        unsigned path;
+    } variants[] = {
+        {"alpha:*\tincomplete\tlost setup\t1\nalpha:stat\tcomplete\t\t1\n"
+         "alpha:cov\tcomplete\t\t1\nalpha:changed\tcomplete\t\t1\nalpha:quiet\tcomplete\t\t1\n"
+         "omega:*\tcomplete\t\t0\n",
+         true, false, false, false, CBM_TEST_SELECT_SETUP_UNKNOWN},
+        {"alpha:*\tcomplete\t\t0\nalpha:stat\tcomplete\t\t1\n"
+         "alpha:cov\tcomplete\t\t1\nalpha:changed\tcomplete\t\t1\nalpha:quiet\tcomplete\t\t1\n",
+         true, false, false, false, CBM_TEST_SELECT_SETUP_HIT},
+        {quiet_rows, true, true, false, false, CBM_TEST_SELECT_STATIC},
+        {quiet_rows, true, false, true, false, CBM_TEST_SELECT_CHANGED},
+        {quiet_rows, true, false, false, true, CBM_TEST_SELECT_RULE},
+        {quiet_rows, false, false, false, false, CBM_TEST_SELECT_ARTIFACT_REJECTED},
+        /* One covered case alone would otherwise name `alpha:cov`. */
+        {"alpha:*\tcomplete\t\t1\nalpha:stat\tcomplete\t\t1\n"
+         "alpha:cov\tcomplete\t\t0\nalpha:changed\tcomplete\t\t1\nalpha:quiet\tcomplete\t\t1\n",
+         true, false, false, false, CBM_TEST_SELECT_COVERAGE},
+    };
+    const char *runners[] = {
+        "void main(void) {\n#if defined(FEATURE) && !defined(_WIN32)\nRUN_SELECTED_SUITE(alpha);\n"
+        "#endif\n}\n",
+        "void main(void) { RUN_SELECTED_SUITE(alpha); }\n",
+    };
+    for (int r = 0; r < 2; r++) {
+        char source[1024];
+        snprintf(source, sizeof(source),
+                 "TEST(stat) {}\nTEST(cov) {}\nTEST(changed) {}\nTEST(quiet) {}\n"
+                 "SUITE(alpha) { RUN_TEST(stat); RUN_TEST(cov); RUN_TEST(changed); "
+                 "RUN_TEST(quiet); }\n%s",
+                 runners[r]);
+        cbm_test_model_t *model = selection_model(source);
+        ASSERT_NOT_NULL(model);
+        for (int i = 0; i < (int)(sizeof(variants) / sizeof(variants[0])); i++) {
+            cbm_coverage_map_t *map = selection_map(variants[i].rows);
+            ASSERT_NOT_NULL(map);
+            cbm_test_reach_t reach[] = SELECTION_REACH;
+            for (int k = 0; k < 4; k++)
+                reach[k].reached = reach[k].changed = false;
+            int changed[] = {0};
+            cbm_test_suite_trigger_t trigger = {.suite = "alpha",
+                                                .reached = variants[i].reached,
+                                                .changed = variants[i].changed,
+                                                .rule = variants[i].rule};
+            cbm_test_selection_input_t input = selection_input(model, map, reach, changed);
+            input.coverage_admitted = variants[i].admitted;
+            input.suite_triggers = &trigger;
+            input.suite_trigger_count = 1;
+            cbm_test_selection_t *result = cbm_test_select(&input);
+            ASSERT_NOT_NULL(result);
+            ASSERT_EQ(cbm_test_selection_run_all(result), 0);
+            int count;
+            const cbm_test_selected_suite_t *suites = cbm_test_selection_suites(result, &count);
+            ASSERT_EQ(count, 1);
+            ASSERT_TRUE(suites[0].reasons & variants[i].path);
+            if (r == 0) {
+                ASSERT_TRUE(suites[0].whole);
+                ASSERT_TRUE(suites[0].reasons & CBM_TEST_SELECT_CONDITIONAL);
+                cbm_test_selection_cases(result, &count);
+                ASSERT_EQ(count, 0);
+            } else {
+                /* Registered in every build: the strict contract stays. */
+                ASSERT_FALSE(suites[0].reasons & CBM_TEST_SELECT_CONDITIONAL);
+            }
+            cbm_test_selection_free(result);
+            cbm_coverage_map_free(map);
+        }
+        cbm_test_model_free(model);
+    }
+    PASS();
+}
+
 /* Uncertainty is scoped to the file it was found in. A file the model cannot
  * read with certainty, but which defines its own suite, makes that suite
  * uncertain (it can only run whole) and leaves every other suite narrowable.
@@ -3804,6 +3917,7 @@ SUITE(test_impact) {
     RUN_TEST(test_selection_setup_and_rejected_artifacts_select_whole_suites);
     RUN_TEST(test_selection_incomplete_global_evidence_never_narrows);
     RUN_TEST(test_selection_inventory_ambiguity_and_conditionals_use_whole_suite);
+    RUN_TEST(test_selection_conditionally_registered_suite_is_conditional_on_every_path);
     RUN_TEST(test_model_uncertainty_is_scoped_to_the_suites_of_its_file);
     RUN_TEST(test_model_only_code_continuations_are_uncertain);
     RUN_TEST(test_selection_scoped_uncertainty_runs_only_its_suite_whole);
@@ -3834,6 +3948,7 @@ SUITE(test_impact) {
     RUN_TEST(test_model_ignores_comments_and_literals);
     RUN_TEST(test_model_reads_suites_written_as_functions);
     RUN_TEST(test_model_marks_what_is_under_a_condition);
+    RUN_TEST(test_model_marks_runner_suites_registered_under_a_condition);
     RUN_TEST(test_model_keeps_brace_depth_across_else_branches);
     RUN_TEST(test_model_resolves_registrations_in_their_own_file);
     RUN_TEST(test_model_marks_suites_that_register_through_a_macro);