PyAPI: support retrieving the exception when running a string

- Optionally get the error as a single line.
- Support access the error as an allocated string.
- PyC_ExceptionBuffer_Simple was always printing to the `stdout` while
  PyC_ExceptionBuffer didn't, now either print to the output.

Without this, callers are unable to do anything with the error string.

source/blender/editors/include/ED_numinput.h

@@ -107,8 +107,9 @@ bool user_string_to_number(bContext *C,
                            const char *str,
                            const struct UnitSettings *unit,
                            int type,
-                           const char *error_prefix,
+                           double *r_value,
-                           double *r_value);
+                           const bool use_single_line_error,
+                           char **r_error);
 
 /** \} */
 

source/blender/editors/interface/interface.c

@@ -52,6 +52,7 @@
 #include "BKE_context.h"
 #include "BKE_idprop.h"
 #include "BKE_main.h"
+#include "BKE_report.h"
 #include "BKE_scene.h"
 #include "BKE_screen.h"
 #include "BKE_unit.h"
@@ -2912,7 +2913,14 @@ char *ui_but_string_get_dynamic(uiBut *but, int *r_str_size)
 static bool ui_number_from_string_units(
     bContext *C, const char *str, const int unit_type, const UnitSettings *unit, double *r_value)
 {
-  return user_string_to_number(C, str, unit, unit_type, UI_NUMBER_EVAL_ERROR_PREFIX, r_value);
+  char *error = NULL;
+  const bool ok = user_string_to_number(C, str, unit, unit_type, r_value, true, &error);
+  if (error) {
+    ReportList *reports = CTX_wm_reports(C);
+    BKE_reportf(reports, RPT_ERROR, "%s: %s", UI_NUMBER_EVAL_ERROR_PREFIX, error);
+    MEM_freeN(error);
+  }
+  return ok;
 }
 
 static bool ui_number_from_string_units_with_but(bContext *C,
@@ -2929,7 +2937,11 @@ static bool ui_number_from_string(bContext *C, const char *str, double *r_value)
 {
   bool ok;
 #ifdef WITH_PYTHON
-  ok = BPY_run_string_as_number(C, NULL, str, UI_NUMBER_EVAL_ERROR_PREFIX, r_value);
+  struct BPy_RunErrInfo err_info = {
+      .reports = CTX_wm_reports(C),
+      .report_prefix = UI_NUMBER_EVAL_ERROR_PREFIX,
+  };
+  ok = BPY_run_string_as_number(C, NULL, str, &err_info, r_value);
 #else
   UNUSED_VARS(C);
   *r_value = atof(str);

source/blender/editors/interface/interface_context_menu.c

@@ -399,7 +399,7 @@ static void ui_but_user_menu_add(bContext *C, uiBut *but, bUserMenu *um)
                    "'%s').label",
                    idname);
           char *expr_result = NULL;
-          if (BPY_run_string_as_string(C, expr_imports, expr, __func__, &expr_result)) {
+          if (BPY_run_string_as_string(C, expr_imports, expr, NULL, &expr_result)) {
             STRNCPY(drawstr, expr_result);
             MEM_freeN(expr_result);
           }

source/blender/editors/interface/interface_region_tooltip.c

@@ -428,7 +428,7 @@ static uiTooltipData *ui_tooltip_data_from_tool(bContext *C, uiBut *but, bool is
     if (has_valid_context == false) {
       expr_result = BLI_strdup(has_valid_context_error);
     }
-    else if (BPY_run_string_as_string(C, expr_imports, expr, __func__, &expr_result)) {
+    else if (BPY_run_string_as_string(C, expr_imports, expr, NULL, &expr_result)) {
       if (STREQ(expr_result, "")) {
         MEM_freeN(expr_result);
         expr_result = NULL;
@@ -485,7 +485,7 @@ static uiTooltipData *ui_tooltip_data_from_tool(bContext *C, uiBut *but, bool is
     if (has_valid_context == false) {
       expr_result = BLI_strdup(has_valid_context_error);
     }
-    else if (BPY_run_string_as_string(C, expr_imports, expr, __func__, &expr_result)) {
+    else if (BPY_run_string_as_string(C, expr_imports, expr, NULL, &expr_result)) {
       if (STREQ(expr_result, ".")) {
         MEM_freeN(expr_result);
         expr_result = NULL;
@@ -589,7 +589,7 @@ static uiTooltipData *ui_tooltip_data_from_tool(bContext *C, uiBut *but, bool is
         if (has_valid_context == false) {
           shortcut = BLI_strdup(has_valid_context_error);
         }
-        else if (BPY_run_string_as_intptr(C, expr_imports, expr, __func__, &expr_result)) {
+        else if (BPY_run_string_as_intptr(C, expr_imports, expr, NULL, &expr_result)) {
           if (expr_result != 0) {
             wmKeyMap *keymap = (wmKeyMap *)expr_result;
             LISTBASE_FOREACH (wmKeyMapItem *, kmi, &keymap->items) {
@@ -654,7 +654,7 @@ static uiTooltipData *ui_tooltip_data_from_tool(bContext *C, uiBut *but, bool is
         /* pass */
       }
       else if (BPY_run_string_as_string_and_size(
-                   C, expr_imports, expr, __func__, &expr_result, &expr_result_len)) {
+                   C, expr_imports, expr, NULL, &expr_result, &expr_result_len)) {
         /* pass. */
       }
     }
@@ -731,7 +731,7 @@ static uiTooltipData *ui_tooltip_data_from_tool(bContext *C, uiBut *but, bool is
     if (has_valid_context == false) {
       /* pass */
     }
-    else if (BPY_run_string_as_intptr(C, expr_imports, expr, __func__, &expr_result)) {
+    else if (BPY_run_string_as_intptr(C, expr_imports, expr, NULL, &expr_result)) {
       if (expr_result != 0) {
         {
           uiTooltipField *field = text_field_add(data,

source/blender/editors/util/numinput.c

@@ -29,6 +29,7 @@
 #include "BLT_translation.h"
 
 #include "BKE_context.h"
+#include "BKE_report.h"
 #include "BKE_scene.h"
 #include "BKE_unit.h"
 
@@ -283,10 +284,15 @@ bool user_string_to_number(bContext *C,
                            const char *str,
                            const UnitSettings *unit,
                            int type,
-                           const char *error_prefix,
+                           double *r_value,
-                           double *r_value)
+                           const bool use_single_line_error,
+                           char **r_error)
 {
 #ifdef WITH_PYTHON
+  struct BPy_RunErrInfo err_info = {
+      .use_single_line_error = use_single_line_error,
+      .r_string = r_error,
+  };
   double unit_scale = BKE_scene_unit_scale(unit, type, 1.0);
   if (BKE_unit_string_contains_unit(str, type)) {
     char str_unit_convert[256];
@@ -294,10 +300,10 @@ bool user_string_to_number(bContext *C,
     BKE_unit_replace_string(
         str_unit_convert, sizeof(str_unit_convert), str, unit_scale, unit->system, type);
 
-    return BPY_run_string_as_number(C, NULL, str_unit_convert, error_prefix, r_value);
+    return BPY_run_string_as_number(C, NULL, str_unit_convert, &err_info, r_value);
   }
 
-  int success = BPY_run_string_as_number(C, NULL, str, error_prefix, r_value);
+  int success = BPY_run_string_as_number(C, NULL, str, &err_info, r_value);
   *r_value = BKE_unit_apply_preferred_unit(unit, type, *r_value);
   *r_value /= unit_scale;
   return success;
@@ -577,10 +583,19 @@ bool handleNumInput(bContext *C, NumInput *n, const wmEvent *event)
   if (n->str[0]) {
     const float val_prev = n->val[idx];
     Scene *sce = CTX_data_scene(C);
+    char *error = NULL;
 
     double val;
     int success = user_string_to_number(
-        C, n->str, &sce->unit, n->unit_type[idx], IFACE_("Numeric input evaluation"), &val);
+        C, n->str, &sce->unit, n->unit_type[idx], &val, false, &error);
+
+    if (error) {
+      ReportList *reports = CTX_wm_reports(C);
+      printf("%s\n", error);
+      BKE_report(reports, RPT_ERROR, error);
+      BKE_report(reports, RPT_ERROR, IFACE_("Numeric input evaluation"));
+      MEM_freeN(error);
+    }
 
     if (success) {
       n->val[idx] = (float)val;

source/blender/python/BPY_extern_run.h

@@ -42,27 +42,43 @@ bool BPY_run_text(struct bContext *C,
 bool BPY_run_string_exec(struct bContext *C, const char *imports[], const char *expr);
 bool BPY_run_string_eval(struct bContext *C, const char *imports[], const char *expr);
 
+/**
+ * \note When this struct is passed in as NULL,
+ * print errors to the `stdout` and clear.
+ */
+struct BPy_RunErrInfo {
+  /** Brief text, single line (can show this in status bar for e.g.). */
+  bool use_single_line_error;
+
+  /** Report with optional prefix (when non-NULL). */
+  struct ReportList *reports;
+  const char *report_prefix;
+
+  /** Allocated exception text (assign when non-NULL). */
+  char **r_string;
+};
+
 /* Run, evaluating to fixed type result. */
 bool BPY_run_string_as_number(struct bContext *C,
                               const char *imports[],
                               const char *expr,
-                              const char *report_prefix,
+                              struct BPy_RunErrInfo *err_info,
                               double *r_value);
 bool BPY_run_string_as_intptr(struct bContext *C,
                               const char *imports[],
                               const char *expr,
-                              const char *report_prefix,
+                              struct BPy_RunErrInfo *err_info,
                               intptr_t *r_value);
 bool BPY_run_string_as_string_and_size(struct bContext *C,
                                        const char *imports[],
                                        const char *expr,
-                                       const char *report_prefix,
+                                       struct BPy_RunErrInfo *err_info,
                                        char **r_value,
                                        size_t *r_value_size);
 bool BPY_run_string_as_string(struct bContext *C,
                               const char *imports[],
                               const char *expr,
-                              const char *report_prefix,
+                              struct BPy_RunErrInfo *err_info,
                               char **r_value);
 
 #ifdef __cplusplus

source/blender/python/generic/py_capi_utils.c

@@ -733,7 +733,6 @@ PyObject *PyC_ExceptionBuffer_Simple(void)
 
   PyErr_Restore(error_type, error_value, error_traceback);
 
-  PyErr_Print();
   PyErr_Clear();
   return string_io_buf;
 }

source/blender/python/intern/bpy_interface_run.c

@@ -31,6 +31,7 @@
 
 #include "BKE_context.h"
 #include "BKE_main.h"
+#include "BKE_report.h"
 #include "BKE_text.h"
 
 #include "DNA_text_types.h"
@@ -294,13 +295,47 @@ bool BPY_run_string_exec(bContext *C, const char *imports[], const char *expr)
  * in code that doesn't deal with Python data-types.
  * \{ */
 
+static void run_string_handle_error(struct BPy_RunErrInfo *err_info)
+{
+  if (err_info == NULL) {
+    PyErr_Print();
+    PyErr_Clear();
+    return;
+  }
+
+  /* Signal to do nothing. */
+  if (!(err_info->reports || err_info->r_string)) {
+    PyErr_Clear();
+    return;
+  }
+
+  PyObject *py_err_str = err_info->use_single_line_error ? PyC_ExceptionBuffer_Simple() :
+                                                           PyC_ExceptionBuffer();
+  const char *err_str = py_err_str ? PyUnicode_AsUTF8(py_err_str) : "Unable to extract exception";
+
+  if (err_info->reports != NULL) {
+    if (err_info->report_prefix) {
+      BKE_reportf(err_info->reports, RPT_ERROR, "%s: %s", err_info->report_prefix, err_str);
+    }
+    else {
+      BKE_report(err_info->reports, RPT_ERROR, err_str);
+    }
+  }
+
+  if (err_info->r_string != NULL) {
+    *err_info->r_string = BLI_strdup(err_str);
+  }
+
+  Py_XDECREF(py_err_str);
+}
+
 /**
  * \return success
  */
 bool BPY_run_string_as_number(bContext *C,
                               const char *imports[],
                               const char *expr,
-                              const char *report_prefix,
+                              struct BPy_RunErrInfo *err_info,
                               double *r_value)
 {
   PyGILState_STATE gilstate;
@@ -320,12 +355,7 @@ bool BPY_run_string_as_number(bContext *C,
   ok = PyC_RunString_AsNumber(imports, expr, "<expr as number>", r_value);
 
   if (ok == false) {
-    if (report_prefix != NULL) {
+    run_string_handle_error(err_info);
-      BPy_errors_to_report_ex(CTX_wm_reports(C), report_prefix, false, false);
-    }
-    else {
-      PyErr_Clear();
-    }
   }
 
   bpy_context_clear(C, &gilstate);
@@ -339,7 +369,7 @@ bool BPY_run_string_as_number(bContext *C,
 bool BPY_run_string_as_string_and_size(bContext *C,
                                        const char *imports[],
                                        const char *expr,
-                                       const char *report_prefix,
+                                       struct BPy_RunErrInfo *err_info,
                                        char **r_value,
                                        size_t *r_value_size)
 {
@@ -357,12 +387,7 @@ bool BPY_run_string_as_string_and_size(bContext *C,
   ok = PyC_RunString_AsStringAndSize(imports, expr, "<expr as str>", r_value, r_value_size);
 
   if (ok == false) {
-    if (report_prefix != NULL) {
+    run_string_handle_error(err_info);
-      BPy_errors_to_report_ex(CTX_wm_reports(C), false, false, report_prefix);
-    }
-    else {
-      PyErr_Clear();
-    }
   }
 
   bpy_context_clear(C, &gilstate);
@@ -373,12 +398,11 @@ bool BPY_run_string_as_string_and_size(bContext *C,
 bool BPY_run_string_as_string(bContext *C,
                               const char *imports[],
                               const char *expr,
-                              const char *report_prefix,
+                              struct BPy_RunErrInfo *err_info,
                               char **r_value)
 {
   size_t value_dummy_size;
-  return BPY_run_string_as_string_and_size(
+  return BPY_run_string_as_string_and_size(C, imports, expr, err_info, r_value, &value_dummy_size);
-      C, imports, expr, report_prefix, r_value, &value_dummy_size);
 }
 
 /**
@@ -389,7 +413,7 @@ bool BPY_run_string_as_string(bContext *C,
 bool BPY_run_string_as_intptr(bContext *C,
                               const char *imports[],
                               const char *expr,
-                              const char *report_prefix,
+                              struct BPy_RunErrInfo *err_info,
                               intptr_t *r_value)
 {
   BLI_assert(r_value && expr);
@@ -406,12 +430,7 @@ bool BPY_run_string_as_intptr(bContext *C,
   ok = PyC_RunString_AsIntPtr(imports, expr, "<expr as intptr>", r_value);
 
   if (ok == false) {
-    if (report_prefix != NULL) {
+    run_string_handle_error(err_info);
-      BPy_errors_to_report_ex(CTX_wm_reports(C), report_prefix, false, false);
-    }
-    else {
-      PyErr_Clear();
-    }
   }
 
   bpy_context_clear(C, &gilstate);