[Bug-1630262], [Bug-1615425]: segfault when deleting lines or tagging outside of the -startline/-endline range with peer text widgets. [Bug-3487407]: Weird text indices.

1 files changed, 45 insertions, 2 deletions

diff --git a/generic/tkText.c b/generic/tkText.c
index 98720d3..d1f489d 100644
--- a/generic/tkText.c
+++ b/generic/tkText.c
@@ -2119,6 +2119,10 @@ ConfigureText(
 	 * Also, clamp the insert and current (unshared) marks to the new
 	 * -startline/-endline range limits of the widget. All other (shared)
 	 * marks are unchanged.
+         * The return value of TkTextMarkNameToIndex does not need to be
+         * checked: "insert" and "current" marks always exist, and the
+         * purpose of the code below precisely is to move them inside the
+         * -startline/-endline range.
 	 */
 
 	textPtr->sharedTextPtr->stateEpoch++;
@@ -3105,6 +3109,11 @@ DeleteIndexRange(
 		resetView = 1;
 		line = line1;
 		byteIndex = tPtr->topIndex.byteIndex;
+            } else {
+                /*
+                 * Deletion range starts after the top line. This peers's view
+                 * will not need to be reset. Nothing to do.
+                 */
 	    }
 	} else if (index2.linePtr == tPtr->topIndex.linePtr) {
 	    /*
@@ -3121,6 +3130,11 @@ DeleteIndexRange(
 	    } else {
 		byteIndex -= (index2.byteIndex - index1.byteIndex);
 	    }
+        } else {
+            /*
+             * Deletion range ends before the top line. This peers's view
+             * will not need to be reset. Nothing to do.
+             */
 	}
 	if (resetView) {
 	    lineAndByteIndex[resetViewCount] = line;
@@ -3165,14 +3179,43 @@ DeleteIndexRange(
 	    TkTextIndex indexTmp;
 
 	    if (tPtr == textPtr) {
-		if (viewUpdate) {
+                if (viewUpdate) {
+                    /*
+                     * line cannot be before -startline of textPtr because
+                     * this line corresponds to an index which is necessarily
+                     * between "1.0" and "end" relative to textPtr.
+                     * Therefore no need to clamp line to the -start/-end
+                     * range.
+                     */
+
 		    TkTextMakeByteIndex(sharedTextPtr->tree, textPtr, line,
 			    byteIndex, &indexTmp);
 		    TkTextSetYView(tPtr, &indexTmp, 0);
 		}
 	    } else {
-		TkTextMakeByteIndex(sharedTextPtr->tree, NULL, line,
+                TkTextMakeByteIndex(sharedTextPtr->tree, tPtr, line,
 			byteIndex, &indexTmp);
+                /*
+                 * line may be before -startline of tPtr and must be
+                 * clamped to -startline before providing it to
+                 * TkTextSetYView otherwise lines before -startline
+                 * would be displayed.
+                 * There is no need to worry about -endline however,
+                 * because the view will only be reset if the deletion
+                 * involves the TOP line of the screen
+                 */
+
+                if (tPtr->start != NULL) {
+                    int start;
+                    TkTextIndex indexStart;
+
+                    start = TkBTreeLinesTo(NULL, tPtr->start);
+                    TkTextMakeByteIndex(sharedTextPtr->tree, NULL, start,
+			    0, &indexStart);
+                    if (TkTextIndexCmp(&indexTmp, &indexStart) < 0) {
+                        indexTmp = indexStart;
+                    }
+                }
 		TkTextSetYView(tPtr, &indexTmp, 0);
 	    }
 	}