tdf#137920 sw: avoid layout loop when inserting at-char anchored large image

Regression from commit d250ca91c79f457102daf4da81446b7f130fb0ee (sw:
insert image: set anchor to at-char by default, 2019-11-18), the problem
was that the document has 2 pages, the first page would host the anchor
of an inserted image and looped while creating/deleting a next page
frame when updating the layout on inserting of an image.

This problem was less visible before, as the at-para anchor is a
different codepath, which was the previous default.

The primary problem is that the loop in SwLayAction::Action() assumes
that we make progress, so in case m_bAgain is set, then doing the layout
again won't re-set m_bAgain, but it happened here.

That happens because each iteration calls SwFrame::InsertPage(),
followed by a SwPageFrame::DestroyImpl(). Examining the backtrace of the
SwPageFrame ctor leads to SwTextFrame::FormatAdjust() which tries to
split the text frame only in case it has either a number portion or a
text portion, but the check there was incomplete: a "none" number format
results in no number portion, leading to this loop.

Fix the problem by checking for HasVisibleNumberingOrBullet() before
assuming that we can split an empty text frame into two pieces where at
least one of them is not empty.

(cherry picked from commit 3e9975cf507e24e9c501575c501833164d217acc)

Change-Id: I454e1ec275ad6c00202e65b97adb79647d11a0b7
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/129395
Tested-by: Jenkins
Reviewed-by: Michael Stahl <michael.stahl@allotropia.de>
Signed-off-by: Xisco Fauli <xiscofauli@libreoffice.org>
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/129410

4 files changed, 87 insertions, 1 deletions

diff --git a/sw/qa/core/text/data/empty-numbering-page-split.fodt b/sw/qa/core/text/data/empty-numbering-page-split.fodt
new file mode 100644
index 000000000000..517ad2e0fb26
--- /dev/null
+++ b/sw/qa/core/text/data/empty-numbering-page-split.fodt
@@ -0,0 +1,62 @@
+<?xml version='1.0' encoding='UTF-8'?>
+<office:document xmlns:text="urn:oasis:names:tc:opendocument:xmlns:text:1.0" xmlns:style="urn:oasis:names:tc:opendocument:xmlns:style:1.0" xmlns:fo="urn:oasis:names:tc:opendocument:xmlns:xsl-fo-compatible:1.0" xmlns:office="urn:oasis:names:tc:opendocument:xmlns:office:1.0" office:version="1.3" office:mimetype="application/vnd.oasis.opendocument.text">
+  <office:styles>
+    <style:default-style style:family="paragraph">
+      <style:text-properties fo:font-size="12pt"/>
+    </style:default-style>
+    <style:style style:name="Standard" style:family="paragraph" style:class="text"/>
+    <style:style style:name="Heading" style:family="paragraph" style:parent-style-name="Standard" style:next-style-name="Text_20_body" style:class="text">
+      <style:paragraph-properties fo:margin-top="0.423cm" fo:margin-bottom="0.212cm" style:contextual-spacing="false" fo:keep-with-next="always"/>
+      <style:text-properties fo:font-size="14pt"/>
+    </style:style>
+    <style:style style:name="Text_20_body" style:display-name="Text body" style:family="paragraph" style:parent-style-name="Standard" style:class="text">
+      <style:paragraph-properties fo:margin-top="0cm" fo:margin-bottom="0.212cm"/>
+    </style:style>
+    <style:style style:name="Heading_20_1" style:display-name="Heading 1" style:family="paragraph" style:parent-style-name="Heading" style:class="text">
+      <style:paragraph-properties fo:margin-top="0.423cm" fo:margin-bottom="0.212cm" fo:break-before="page"/>
+    </style:style>
+    <text:outline-style style:name="Outline">
+      <text:outline-level-style text:level="1" style:num-format="">
+        <style:list-level-properties text:min-label-distance="0.381cm"/>
+      </text:outline-level-style>
+    </text:outline-style>
+  </office:styles>
+  <office:automatic-styles>
+    <style:style style:name="P1" style:family="paragraph" style:parent-style-name="Standard" style:master-page-name="Intro">
+      <style:paragraph-properties style:page-number="1"/>
+    </style:style>
+    <style:page-layout style:name="pm1">
+      <style:page-layout-properties fo:page-width="21.001cm" fo:page-height="29.7cm" fo:margin-top="2cm" fo:margin-bottom="2cm" fo:margin-left="2cm" fo:margin-right="2cm"/>
+      <style:header-style>
+        <style:header-footer-properties fo:min-height="0cm" fo:margin-left="0cm" fo:margin-right="0cm" fo:margin-bottom="0cm"/>
+      </style:header-style>
+      <style:footer-style>
+        <style:header-footer-properties fo:min-height="0.6cm" fo:margin-left="0cm" fo:margin-right="0cm" fo:margin-top="0.499cm" style:dynamic-spacing="false"/>
+      </style:footer-style>
+    </style:page-layout>
+    <style:page-layout style:name="pm2">
+      <style:page-layout-properties fo:page-width="21.001cm" fo:page-height="29.7cm" fo:margin-top="2cm" fo:margin-bottom="2cm" fo:margin-left="2cm" fo:margin-right="2cm"/>
+      <style:header-style>
+        <style:header-footer-properties fo:min-height="0cm" fo:margin-left="0cm" fo:margin-right="0cm" fo:margin-bottom="0.499cm"/>
+      </style:header-style>
+      <style:footer-style/>
+    </style:page-layout>
+  </office:automatic-styles>
+  <office:master-styles>
+    <style:master-page style:name="Standard" style:page-layout-name="pm1" style:next-style-name="Intro">
+      <style:header>
+        <text:p/>
+      </style:header>
+      <style:footer>
+        <text:p/>
+      </style:footer>
+    </style:master-page>
+    <style:master-page style:name="Intro" style:page-layout-name="pm2"/>
+  </office:master-styles>
+  <office:body>
+    <office:text text:use-soft-page-breaks="true">
+      <text:h text:style-name="Heading_20_1" text:outline-level="1"/>
+      <text:p text:style-name="P1"/>
+    </office:text>
+  </office:body>
+</office:document>
diff --git a/sw/qa/core/text/data/image.png b/sw/qa/core/text/data/image.png
new file mode 100644
index 000000000000..49e71b07ae8b
--- /dev/null
+++ b/sw/qa/core/text/data/image.png
diff --git a/sw/qa/core/text/text.cxx b/sw/qa/core/text/text.cxx
index 4db880e687f4..5f1b89e34247 100644
--- a/sw/qa/core/text/text.cxx
+++ b/sw/qa/core/text/text.cxx
@@ -135,6 +135,22 @@ CPPUNIT_TEST_FIXTURE(SwCoreTextTest, testTabOverMarginSection)
     CPPUNIT_ASSERT_LESS(static_cast<sal_Int32>(5000), nWidth);
 }
 
+CPPUNIT_TEST_FIXTURE(SwCoreTextTest, testEmptyNumberingPageSplit)
+{
+    // Given a document with 2 pages: the only para on page 1 is a numbering without a number
+    // portion:
+    createSwDoc(DATA_DIRECTORY, "empty-numbering-page-split.fodt");
+
+    // When inserting an image that doesn't fit the body frame:
+    // Then make sure that the layout update after insertion finishes:
+    uno::Sequence<beans::PropertyValue> aArgs = {
+        comphelper::makePropertyValue("FileName",
+                                      m_directories.getURLFromSrc(DATA_DIRECTORY) + "image.png"),
+    };
+    // Without the accompanying fix in place, this never finished.
+    dispatchCommand(mxComponent, ".uno:InsertGraphic", aArgs);
+}
+
 CPPUNIT_PLUGIN_IMPLEMENT();
 
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/sw/source/core/text/frmform.cxx b/sw/source/core/text/frmform.cxx
index f9f6935e9a9d..bdd3f1d9d17c 100644
--- a/sw/source/core/text/frmform.cxx
+++ b/sw/source/core/text/frmform.cxx
@@ -1117,13 +1117,21 @@ void SwTextFrame::FormatAdjust( SwTextFormatter &rLine,
         }
         else
         {
+            const SwTextNode* pTextNode = GetTextNodeForParaProps();
+            bool bHasVisibleNumRule = nStrLen == TextFrameIndex(0) && pTextNode->GetNumRule();
+
+            if (!pTextNode->HasVisibleNumberingOrBullet())
+            {
+                bHasVisibleNumRule = false;
+            }
+
             // Only split frame, if the frame contains
             // content or contains no content, but has a numbering.
             // i#84870 - No split, if text frame only contains one
             // as-character anchored object.
             if ( !bOnlyContainsAsCharAnchoredObj &&
                  (nStrLen > TextFrameIndex(0) ||
-                   (nStrLen == TextFrameIndex(0) && GetTextNodeForParaProps()->GetNumRule()))
+                   bHasVisibleNumRule )
                )
             {
                 SplitFrame( nEnd );