Fix #1620: don't attach image on paste when clipboard also has text

When the clipboard carries both text and an image (rich-text sources like
Notes, Word, Slack, browser selection attach a rendered preview alongside
the plain text), the paste handler in static/boot.js unconditionally
called e.preventDefault() and routed the image into addFiles(), silently
discarding the text payload.

Fix:
  - Detect text in the clipboard via items[].kind === 'string' &&
    (type === 'text/plain' || type === 'text/html'). When present, return
    early so the browser's default text-paste runs.
  - Tighten the image filter to kind === 'file' && type.startsWith('image/')
    so string items advertising an image MIME (e.g. text/html with an
    embedded data URI) are not misclassified as a true screenshot paste.

Pure-screenshot paste (image-only clipboard, e.g. Cmd+Shift+Ctrl+4 on macOS)
is unchanged.

Adds tests/test_1620_paste_text_with_image.py with 6 static-analysis checks
on the handler shape, matching the pattern of test_issue1095_pasted_images.py.

static/boot.js

@@ -965,8 +965,15 @@ document.addEventListener('keydown',async e=>{
 });
 $('msg').addEventListener('paste',e=>{
   const items=Array.from(e.clipboardData?.items||[]);
-  const imageItems=items.filter(i=>i.type.startsWith('image/'));
-  if(!imageItems.length)return;
+  // When the clipboard carries BOTH text and an image (common from Notes,
+  // Word, browsers, Slack — the OS attaches a rendered preview alongside
+  // the plain text), prefer the text and let the browser paste normally.
+  // Only intercept when the clipboard is image-only (true screenshot paste).
+  // Tighten the image filter to kind==='file' so string items advertising an
+  // image MIME (e.g. text/html with an embedded data URI) are not misclassified.
+  const hasText=items.some(i=>i.kind==='string'&&(i.type==='text/plain'||i.type==='text/html'));
+  const imageItems=items.filter(i=>i.kind==='file'&&i.type.startsWith('image/'));
+  if(!imageItems.length||hasText)return;
   e.preventDefault();
   const files=imageItems.map(i=>{
     const blob=i.getAsFile();

tests/test_1620_paste_text_with_image.py

@@ -0,0 +1,105 @@
+"""Tests for #1620 — Cmd+V always attaches an image when clipboard contains both text and image.
+
+The composer paste handler in `static/boot.js` previously intercepted any paste
+event whose clipboard carried an `image/*` item, called `e.preventDefault()`,
+and attached the image as a screenshot. When the clipboard came from a rich-text
+source (Notes, Word, Slack, browser selection), macOS/Windows/Linux attach a
+rendered preview image alongside the plain text — so the handler swallowed the
+text payload and only the rogue image was attached.
+
+The fix:
+  • Skip image-attach when the clipboard also carries `text/plain` or `text/html`
+    string items (rich-text source — let the browser paste text normally).
+  • Tighten the image filter to `kind === 'file'` so string items advertising an
+    image MIME are not misclassified as a true screenshot paste.
+
+These tests guard the handler shape against regression by static-analyzing
+`static/boot.js`. They follow the same pattern as `test_issue1095_pasted_images.py`.
+"""
+import os
+import re
+
+
+def _read_boot_js() -> str:
+    with open(os.path.join('static', 'boot.js')) as f:
+        return f.read()
+
+
+def _paste_handler_body() -> str:
+    """Extract the body of the #msg paste handler for assertions."""
+    src = _read_boot_js()
+    m = re.search(r"\$\('msg'\)\.addEventListener\('paste',\s*e\s*=>\s*\{", src)
+    assert m, "#msg paste handler not found in static/boot.js"
+    # Walk braces from the opening { to find the matching close.
+    start = m.end() - 1
+    depth = 0
+    for i in range(start, len(src)):
+        c = src[i]
+        if c == '{':
+            depth += 1
+        elif c == '}':
+            depth -= 1
+            if depth == 0:
+                return src[start:i + 1]
+    raise AssertionError("Unbalanced braces in #msg paste handler")
+
+
+class TestPasteHandlerTextWithImage:
+    """Regression suite for #1620."""
+
+    def test_handler_detects_text_in_clipboard(self):
+        """Handler must inspect string items for text/plain or text/html so it can
+        defer to the browser's default text-paste behavior when text is present."""
+        body = _paste_handler_body()
+        assert "kind==='string'" in body or 'kind === "string"' in body or "kind === 'string'" in body, (
+            "paste handler must check items[].kind === 'string' to detect text payload"
+        )
+        assert "'text/plain'" in body, "paste handler must check for text/plain"
+        assert "'text/html'" in body, "paste handler must check for text/html"
+
+    def test_image_filter_requires_kind_file(self):
+        """Image filter must require kind === 'file' to avoid misclassifying string
+        items that advertise an image MIME (e.g. text/html with embedded data URIs)."""
+        body = _paste_handler_body()
+        # The image filter line must combine kind==='file' with type.startsWith('image/').
+        assert re.search(
+            r"kind\s*===\s*'file'\s*&&\s*[a-zA-Z_$][\w$]*\.type\.startsWith\('image/'\)",
+            body,
+        ), "imageItems filter must use kind === 'file' && type.startsWith('image/')"
+
+    def test_handler_skips_attach_when_text_present(self):
+        """The early-return guard must short-circuit when text is in the clipboard,
+        so the browser's default text-paste runs and no image is attached."""
+        body = _paste_handler_body()
+        # Guard shape: if(!imageItems.length || hasText) return;
+        assert re.search(
+            r"if\s*\(\s*!\s*imageItems\.length\s*\|\|\s*hasText\s*\)\s*return\s*;",
+            body,
+        ), "guard must early-return when there are no image files OR text is present"
+
+    def test_handler_still_intercepts_pure_screenshot_paste(self):
+        """Pure-screenshot paste (image-only clipboard) must still call preventDefault()
+        and route through addFiles() so the screenshot attaches as a file."""
+        body = _paste_handler_body()
+        assert 'e.preventDefault()' in body, "handler must still preventDefault on image-only paste"
+        assert 'addFiles(files)' in body, "handler must still call addFiles(files) for screenshots"
+        assert 'screenshot-' in body, "handler must still synthesize screenshot-<ts> filename"
+
+    def test_handler_does_not_use_loose_image_check(self):
+        """The pre-fix loose check `i.type.startsWith('image/')` (without kind==='file')
+        must not be the imageItems filter — that was the source of the bug."""
+        body = _paste_handler_body()
+        # Find the imageItems assignment line.
+        m = re.search(r"const\s+imageItems\s*=\s*items\.filter\([^)]*\)", body)
+        assert m, "imageItems filter not found"
+        filter_expr = m.group(0)
+        assert "kind==='file'" in filter_expr or "kind === 'file'" in filter_expr, (
+            "imageItems filter must be tightened with kind === 'file' (regression for #1620)"
+        )
+
+    def test_handler_does_not_lose_status_message(self):
+        """The image_pasted status message must still be emitted on the screenshot path."""
+        body = _paste_handler_body()
+        assert "setStatus(t('image_pasted')" in body, (
+            "handler must still emit the image_pasted status on screenshot attach"
+        )