InputText: Fixed an undo-state corruption issue when editing buffer before reactivating item. (#4947) + Metrics: Added "InputText" section.

docs/CHANGELOG.txt

@@ -88,6 +88,7 @@ Other Changes:
   trickled with the new input queue (happened on some backends only). (#2467, #1336)
 - InputText: Fixed a one-frame display glitch where pressing Escape to revert after a deletion
   would lead to small garbage being displayed for one frame. Curiously a rather old bug! (#3008)
+- InputText: Fixed an undo-state corruption issue when editing buffer before reactivating item. (#4947)
 - Tables: Fixed incorrect border height used for logic when resizing one of several synchronized
   instance of a same table ID, when instances have a different height. (#3955).
 - Tables: Fixed incorrect auto-fit of parent windows when using non-resizable weighted columns. (#5276)
@@ -108,6 +109,7 @@ Other Changes:
   you have a UTF-8 text encoding issue or a font loading issue. [@LaMarche05, @ocornut]
 - Demo: Add better demo of how to use SetNextFrameWantCaptureMouse()/SetNextFrameWantCaptureKeyboard().
 - Metrics: Added a "UTF-8 Encoding Viewer" section using the aforementioned DebugTextEncoding() function.
+- Metrics: Added "InputText" section to visualize internal state (#4947, #4949).
 - Misc: Fixed calling GetID("label") _before_ a widget emitting this item inside a group (such as InputInt())
   from causing an assertion when closing the group. (#5181).
 - Misc: Fixed IsAnyItemHovered() returning false when using navigation.

imgui.cpp

@@ -12480,6 +12480,13 @@ void ImGui::ShowMetricsWindow(bool* p_open)
         TreePop();
     }
 
+    // Details for InputText
+    if (TreeNode("InputText"))
+    {
+        DebugNodeInputTextState(&g.InputTextState);
+        TreePop();
+    }
+
     // Details for Docking
 #ifdef IMGUI_HAS_DOCK
     if (TreeNode("Docking"))

imgui.h

@@ -65,7 +65,7 @@ Index of this file:
 // Version
 // (Integer encoded as XYYZZ for use in #if preprocessor conditionals. Work in progress versions typically starts at XYY99 then bounce up to XYY00, XYY01 etc. when release tagging happens)
 #define IMGUI_VERSION               "1.88 WIP"
-#define IMGUI_VERSION_NUM           18726
+#define IMGUI_VERSION_NUM           18727
 #define IMGUI_CHECKVERSION()        ImGui::DebugCheckVersionAndDataLayout(IMGUI_VERSION, sizeof(ImGuiIO), sizeof(ImGuiStyle), sizeof(ImVec2), sizeof(ImVec4), sizeof(ImDrawVert), sizeof(ImDrawIdx))
 #define IMGUI_HAS_TABLE
 

imgui_internal.h

@@ -2878,6 +2878,7 @@ namespace ImGui
     IMGUI_API void          DebugNodeTabBar(ImGuiTabBar* tab_bar, const char* label);
     IMGUI_API void          DebugNodeTable(ImGuiTable* table);
     IMGUI_API void          DebugNodeTableSettings(ImGuiTableSettings* settings);
+    IMGUI_API void          DebugNodeInputTextState(ImGuiInputTextState* state);
     IMGUI_API void          DebugNodeWindow(ImGuiWindow* window, const char* label);
     IMGUI_API void          DebugNodeWindowSettings(ImGuiWindowSettings* settings);
     IMGUI_API void          DebugNodeWindowsList(ImVector<ImGuiWindow*>* windows, const char* label);

imgui_widgets.cpp

@@ -3571,6 +3571,7 @@ bool ImGui::InputDouble(const char* label, double* v, double step, double step_f
 // - InputTextReindexLines() [Internal]
 // - InputTextReindexLinesRange() [Internal]
 // - InputTextEx() [Internal]
+// - DebugNodeInputTextState() [Internal]
 //-------------------------------------------------------------------------
 
 bool ImGui::InputText(const char* label, char* buf, size_t buf_size, ImGuiInputTextFlags flags, ImGuiInputTextCallback callback, void* user_data)
@@ -4048,17 +4049,21 @@ bool ImGui::InputTextEx(const char* label, const char* hint, char* buf, int buf_
         state->InitialTextA.resize(buf_len + 1);    // UTF-8. we use +1 to make sure that .Data is always pointing to at least an empty string.
         memcpy(state->InitialTextA.Data, buf, buf_len + 1);
 
+        // Preserve cursor position and undo/redo stack if we come back to same widget
+        // FIXME: Since we reworked this on 2022/06, may want to differenciate recycle_cursor vs recycle_undostate?
+        bool recycle_state = (state->ID == id && !init_changed_specs);
+        if (recycle_state && (state->CurLenA != buf_len || (state->TextAIsValid && strncmp(state->TextA.Data, buf, buf_len) != 0)))
+            recycle_state = false;
+
         // Start edition
         const char* buf_end = NULL;
+        state->ID = id;
         state->TextW.resize(buf_size + 1);          // wchar count <= UTF-8 count. we use +1 to make sure that .Data is always pointing to at least an empty string.
         state->TextA.resize(0);
         state->TextAIsValid = false;                // TextA is not valid yet (we will display buf until then)
         state->CurLenW = ImTextStrFromUtf8(state->TextW.Data, buf_size, buf, NULL, &buf_end);
         state->CurLenA = (int)(buf_end - buf);      // We can't get the result from ImStrncpy() above because it is not UTF-8 aware. Here we'll cut off malformed UTF-8.
 
-        // Preserve cursor position and undo/redo stack if we come back to same widget
-        // FIXME: For non-readonly widgets we might be able to require that TextAIsValid && TextA == buf ? (untested) and discard undo stack if user buffer has changed.
-        const bool recycle_state = (state->ID == id && !init_changed_specs);
         if (recycle_state)
         {
             // Recycle existing cursor/selection/undo stack but clamp position
@@ -4067,7 +4072,6 @@ bool ImGui::InputTextEx(const char* label, const char* hint, char* buf, int buf_
         }
         else
         {
-            state->ID = id;
             state->ScrollX = 0.0f;
             stb_textedit_initialize_state(&state->Stb, !is_multiline);
         }
@@ -4816,6 +4820,40 @@ bool ImGui::InputTextEx(const char* label, const char* hint, char* buf, int buf_
         return value_changed;
 }
 
+void ImGui::DebugNodeInputTextState(ImGuiInputTextState* state)
+{
+#ifndef IMGUI_DISABLE_METRICS_WINDOW
+    ImGuiContext& g = *GImGui;
+    ImStb::STB_TexteditState* stb_state = &state->Stb;
+    ImStb::StbUndoState* undo_state = &stb_state->undostate;
+    Text("ID: 0x%08X, ActiveID: 0x%08X", state->ID, g.ActiveId);
+    Text("CurLenW: %d, CurLenA: %d, Cursor: %d, Selection: %d..%d", state->CurLenA, state->CurLenW, stb_state->cursor, stb_state->select_start, stb_state->select_end);
+    Text("undo_point: %d, redo_point: %d, undo_char_point: %d, redo_char_point: %d", undo_state->undo_point, undo_state->redo_point, undo_state->undo_char_point, undo_state->redo_char_point);
+    if (BeginChild("undopoints", ImVec2(0.0f, GetTextLineHeight() * 15), true)) // Visualize undo state
+    {
+        PushStyleVar(ImGuiStyleVar_ItemSpacing, ImVec2(0, 0));
+        for (int n = 0; n < STB_TEXTEDIT_UNDOSTATECOUNT; n++)
+        {
+            ImStb::StbUndoRecord* undo_rec = &undo_state->undo_rec[n];
+            const char undo_rec_type = (n < undo_state->undo_point) ? 'u' : (n >= undo_state->redo_point) ? 'r' : ' ';
+            if (undo_rec_type == ' ')
+                BeginDisabled();
+            char buf[64] = "";
+            if (undo_rec_type != ' ' && undo_rec->char_storage != -1)
+                ImTextStrToUtf8(buf, IM_ARRAYSIZE(buf), undo_state->undo_char + undo_rec->char_storage, undo_state->undo_char + undo_rec->char_storage + undo_rec->insert_length);
+            Text("%c [%02d] where %03d, insert %03d, delete %03d, char_storage %03d \"%s\"",
+                undo_rec_type, n, undo_rec->where, undo_rec->insert_length, undo_rec->delete_length, undo_rec->char_storage, buf);
+            if (undo_rec_type == ' ')
+                EndDisabled();
+        }
+        PopStyleVar();
+    }
+    EndChild();
+#else
+    IM_UNUSED(state);
+#endif
+}
+
 //-------------------------------------------------------------------------
 // [SECTION] Widgets: ColorEdit, ColorPicker, ColorButton, etc.
 //-------------------------------------------------------------------------