From 35aa0c0968b6d78af73bb664534831f194c3f178 Mon Sep 17 00:00:00 2001
From: GitHub Copilot <copilot@github.com>
Date: Wed, 28 Jan 2026 00:35:21 +0000
Subject: [PATCH] Enhance terminal readiness checks with comprehensive FitAddon
 validation

- Added more robust terminal readiness checking
- Explicitly check for viewport.scrollBarWidth being defined
- Added FitAddon function type checking before calling fit()
- Improved error handling for FitAddon initialization issues
- Prevents 'undefined is not an object' errors during terminal setup
- Maintains all existing functionality and test compatibility

Bump version to 0.3.29

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>
---
 pyproject.toml                            |  2 +-
 src/textual_webterm/static/js/terminal.js | 33 +++++++++++---
 src/textual_webterm/static/js/terminal.ts | 52 +++++++++++++++++++----
 3 files changed, 73 insertions(+), 14 deletions(-)

diff --git a/pyproject.toml b/pyproject.toml
index d4cc9d9..95cb5f8 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "textual-webterm"
-version = "0.3.28"
+version = "0.3.29"
 description = "Serve terminal sessions over the web"
 authors = ["Will McGugan <will@textualize.io>"]
 license = "MIT"
diff --git a/src/textual_webterm/static/js/terminal.js b/src/textual_webterm/static/js/terminal.js
index 63e1935..9d7db88 100644
--- a/src/textual_webterm/static/js/terminal.js
+++ b/src/textual_webterm/static/js/terminal.js
@@ -14551,8 +14551,12 @@ class WebTerminal {
       this.resizeState.isResizing = true;
       this.resizeState.resizeAttempts++;
       this.lastResizeTime = now;
-      this.fitAddon.fit();
-      this.resizeState.resizeAttempts = 0;
+      if (this.fitAddon && typeof this.fitAddon.fit === "function") {
+        this.fitAddon.fit();
+        this.resizeState.resizeAttempts = 0;
+      } else {
+        throw new Error("FitAddon not properly initialized");
+      }
     } catch (e) {
       console.warn("Fit failed:", e);
       this.handleResizeFailure();
@@ -14576,21 +14580,40 @@ class WebTerminal {
   }
   isTerminalReady() {
     try {
-      if (!this.terminal || !this.terminal._core) {
+      if (!this.terminal) {
+        return false;
+      }
+      if (!this.terminal._core) {
         return false;
       }
       const core = this.terminal._core;
-      if (!core.viewport || !core.viewport.scrollBarWidth) {
+      if (!core.viewport) {
+        return false;
+      }
+      if (core.viewport.scrollBarWidth === undefined) {
+        return false;
+      }
+      if (!core._renderService) {
         return false;
       }
       const renderService = core._renderService;
-      if (!renderService || !renderService.dimensions) {
+      if (!renderService.dimensions) {
         return false;
       }
       const dims = renderService.dimensions;
       if (dims.css.cell.width === 0 || dims.css.cell.height === 0) {
         return false;
       }
+      if (this.fitAddon) {
+        try {
+          const fitTerminal = this.fitAddon._terminal;
+          if (!fitTerminal || fitTerminal !== this.terminal) {
+            return false;
+          }
+        } catch (e) {
+          return false;
+        }
+      }
       return true;
     } catch (e) {
       console.warn("Terminal readiness check failed:", e);
diff --git a/src/textual_webterm/static/js/terminal.ts b/src/textual_webterm/static/js/terminal.ts
index 3d0bc72..9158a8e 100644
--- a/src/textual_webterm/static/js/terminal.ts
+++ b/src/textual_webterm/static/js/terminal.ts
@@ -209,8 +209,13 @@ class WebTerminal {
       this.resizeState.resizeAttempts++;
       this.lastResizeTime = now;
       
-      this.fitAddon.fit();
-      this.resizeState.resizeAttempts = 0; // Reset on success
+      // Wrap FitAddon operation in additional safety check
+      if (this.fitAddon && typeof this.fitAddon.fit === 'function') {
+        this.fitAddon.fit();
+        this.resizeState.resizeAttempts = 0; // Reset on success
+      } else {
+        throw new Error("FitAddon not properly initialized");
+      }
       
     } catch (e) {
       console.warn("Fit failed:", e);
@@ -244,28 +249,59 @@ class WebTerminal {
   /** Check if terminal is ready for resize operations */
   private isTerminalReady(): boolean {
     try {
-      // Check if terminal and its core components are initialized
-      if (!this.terminal || !this.terminal._core) {
+      // Check if terminal exists
+      if (!this.terminal) {
         return false;
       }
       
+      // Check if terminal core is initialized
+      if (!this.terminal._core) {
+        return false;
+      }
+      
+      const core = this.terminal._core;
+      
       // Check if viewport is available (FitAddon requirement)
-      const core = this.terminal._core;
-      if (!core.viewport || !core.viewport.scrollBarWidth) {
+      if (!core.viewport) {
         return false;
       }
       
-      // Check if render service has valid dimensions
+      // Check if viewport has scrollBarWidth (this is what was failing)
+      if (core.viewport.scrollBarWidth === undefined) {
+        return false;
+      }
+      
+      // Check if render service exists
+      if (!core._renderService) {
+        return false;
+      }
+      
+      // Check if render service has dimensions
       const renderService = core._renderService;
-      if (!renderService || !renderService.dimensions) {
+      if (!renderService.dimensions) {
         return false;
       }
       
+      // Check if cell dimensions are valid
       const dims = renderService.dimensions;
       if (dims.css.cell.width === 0 || dims.css.cell.height === 0) {
         return false;
       }
       
+      // Additional safety check for FitAddon internal state
+      if (this.fitAddon) {
+        try {
+          // Try to access FitAddon's terminal reference
+          const fitTerminal = (this.fitAddon as any)._terminal;
+          if (!fitTerminal || fitTerminal !== this.terminal) {
+            return false;
+          }
+        } catch (e) {
+          // FitAddon might not have the expected structure
+          return false;
+        }
+      }
+      
       return true;
     } catch (e) {
       console.warn("Terminal readiness check failed:", e);