patch 9.1.0743: diff mode does not handle overlapping diffs correctlyv9.1.0743

Problem:  diff mode does not handle overlapping diffs correctly
Solution: correct the logic to handle overlapping blocks
          (Yukihiro Nakadaira)

Vim merges overlapped diff blocks and it doesn't work expectedly
in some situation.

closes: #15735

Signed-off-by: Yukihiro Nakadaira <yukihiro.nakadaira@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

43 files changed, 1016 insertions, 7 deletions

diff --git a/src/diff.c b/src/diff.c
index 70e2814399..ebe409e5f3 100644
--- a/src/diff.c
+++ b/src/diff.c
@@ -1803,7 +1803,10 @@ diff_read(
 	    {
 		for (i = idx_orig; i < idx_new; ++i)
 		    if (curtab->tp_diffbuf[i] != NULL)
+		    {
 			dp->df_lnum[i] -= off;
+			dp->df_count[i] += off;
+		    }
 		dp->df_lnum[idx_new] = hunk->lnum_new;
 		dp->df_count[idx_new] = hunk->count_new;
 	    }
@@ -1815,9 +1818,7 @@ diff_read(
 	    }
 	    else
 		// second overlap of new block with existing block
-		dp->df_count[idx_new] += hunk->count_new - hunk->count_orig
-		    + dpl->df_lnum[idx_orig] + dpl->df_count[idx_orig]
-		    - (dp->df_lnum[idx_orig] + dp->df_count[idx_orig]);
+		dp->df_count[idx_new] += hunk->count_new;
 
 	    // Adjust the size of the block to include all the lines to the
 	    // end of the existing block or the new diff, whatever ends last.
@@ -1825,10 +1826,8 @@ diff_read(
 			 - (dpl->df_lnum[idx_orig] + dpl->df_count[idx_orig]);
 	    if (off < 0)
 	    {
-		// new change ends in existing block, adjust the end if not
-		// done already
-		if (notset)
-		    dp->df_count[idx_new] += -off;
+		// new change ends in existing block, adjust the end
+		dp->df_count[idx_new] += -off;
 		off = 0;
 	    }
 	    for (i = idx_orig; i < idx_new; ++i)
diff --git a/src/testdir/dumps/Test_diff_overlapped_2.01.dump b/src/testdir/dumps/Test_diff_overlapped_2.01.dump
new file mode 100644
index 0000000000..b5ed36e010
--- /dev/null
+++ b/src/testdir/dumps/Test_diff_overlapped_2.01.dump
@@ -0,0 +1,20 @@
+| +0#0000e05#a8a8a8255@1|a+2#0000000#ff404010| +0&#ffd7ff255@33||+1&#ffffff0| +0#0000e05#a8a8a8255@1|x+2#0000000#ff404010| +0&#ffd7ff255@33
+| +0#0000e05#a8a8a8255@1|b+2#0000000#ff404010| +0&#ffd7ff255@33||+1&#ffffff0| +0#0000e05#a8a8a8255@1|x+2#0000000#ff404010| +0&#ffd7ff255@33
+|~+0#4040ff13#ffffff0| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|X+3#0000000&|d|i|f|i|l|e|1| @10|1|,|1| @11|A|l@1| |X+1&&|d|i|f|i|l|e|2| @10|1|,|1| @11|A|l@1
+|:+0&&> @73
diff --git a/src/testdir/dumps/Test_diff_overlapped_2.02.dump b/src/testdir/dumps/Test_diff_overlapped_2.02.dump
new file mode 100644
index 0000000000..a20c33a5cd
--- /dev/null
+++ b/src/testdir/dumps/Test_diff_overlapped_2.02.dump
@@ -0,0 +1,20 @@
+| +0#0000e05#a8a8a8255@1|a+2#0000000#ff404010| +0&#ffd7ff255@33||+1&#ffffff0| +0#0000e05#a8a8a8255@1|x+2#0000000#ff404010| +0&#ffd7ff255@33
+| +0#0000e05#a8a8a8255@1|b+0#0000000#5fd7ff255| @33||+1&#ffffff0| +0#0000e05#a8a8a8255@1|-+0#4040ff13#afffff255@34
+| +0#0000e05#a8a8a8255@1|c+0#0000000#ffffff0| @33||+1&&| +0#0000e05#a8a8a8255@1|c+0#0000000#ffffff0| @33
+|~+0#4040ff13&| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|X+3#0000000&|d|i|f|i|l|e|1| @10|1|,|1| @11|A|l@1| |X+1&&|d|i|f|i|l|e|2| @10|1|,|1| @11|A|l@1
+|:+0&&> @73
diff --git a/src/testdir/dumps/Test_diff_overlapped_2.03.dump b/src/testdir/dumps/Test_diff_overlapped_2.03.dump
new file mode 100644
index 0000000000..d3be5a1f47
--- /dev/null
+++ b/src/testdir/dumps/Test_diff_overlapped_2.03.dump
@@ -0,0 +1,20 @@
+| +0#0000e05#a8a8a8255@1|a+2#0000000#ff404010| +0&#ffd7ff255@33||+1&#ffffff0| +0#0000e05#a8a8a8255@1|x+2#0000000#ff404010| +0&#ffd7ff255@33
+| +0#0000e05#a8a8a8255@1|-+0#4040ff13#afffff255@34||+1#0000000#ffffff0| +0#0000e05#a8a8a8255@1|x+0#0000000#5fd7ff255| @33
+| +0#0000e05#a8a8a8255@1|c+0#0000000#ffffff0| @33||+1&&| +0#0000e05#a8a8a8255@1|c+0#0000000#ffffff0| @33
+|~+0#4040ff13&| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|X+3#0000000&|d|i|f|i|l|e|1| @10|1|,|1| @11|A|l@1| |X+1&&|d|i|f|i|l|e|2| @10|1|,|1| @11|A|l@1
+|:+0&&> @73
diff --git a/src/testdir/dumps/Test_diff_overlapped_3.01.dump b/src/testdir/dumps/Test_diff_overlapped_3.01.dump
new file mode 100644
index 0000000000..c7d69c0e19
--- /dev/null
+++ b/src/testdir/dumps/Test_diff_overlapped_3.01.dump
@@ -0,0 +1,20 @@
+| +0#0000e05#a8a8a8255@1|a+2#0000000#ff404010| +0&#ffd7ff255@21||+1&#ffffff0| +0#0000e05#a8a8a8255@1|a+2#0000000#ff404010| +0&#ffd7ff255@20||+1&#ffffff0| +0#0000e05#a8a8a8255@1|y+2#0000000#ff404010| +0&#ffd7ff255@20
+| +0#0000e05#a8a8a8255@1|b+2#0000000#ff404010| +0&#ffd7ff255@21||+1&#ffffff0| +0#0000e05#a8a8a8255@1|x+2#0000000#ff404010| +0&#ffd7ff255@20||+1&#ffffff0| +0#0000e05#a8a8a8255@1|b+2#0000000#ff404010| +0&#ffd7ff255@20
+| +0#0000e05#a8a8a8255@1|c+0#0000000#ffffff0| @21||+1&&| +0#0000e05#a8a8a8255@1|c+0#0000000#ffffff0| @20||+1&&| +0#0000e05#a8a8a8255@1|c+0#0000000#ffffff0| @20
+|~+0#4040ff13&| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
+|X+3#0000000&|d|i|f|i|l|e|1| @4|1|,|1| @5|A|l@1| |X+1&&|d|i|f|i|l|e|2| @3|1|,|1| @5|A|l@1| |X|d|i|f|i|l|e|3| @3|1|,|1| @5|A|l@1
+|:+0&&> @73
diff --git a/src/testdir/dumps/Test_diff_overlapped_3.02.dump b/src/testdir/dumps/Test_diff_overlapped_3.02.dump
new file mode 100644
index 0000000000..70fde31247
--- /dev/null
+++ b/src/testdir/dumps/Test_diff_overlapped_3.02.dump
@@ -0,0 +1,20 @@
+| +0#0000e05#a8a8a8255@1|a+0#0000000#ffffff0| @21||+1&&| +0#0000e05#a8a8a8255@1|a+0#0000000#ffffff0| @20||+1&&| +0#0000e05#a8a8a8255@1|a+0#0000000#ffffff0| @20
+| +0#0000e05#a8a8a8255@1|b+2#0000000#ff404010| +0&#ffd7ff255@21||+1&#ffffff0| +0#0000e05#a8a8a8255@1|x+2#0000000#ff404010| +0&#ffd7ff255@20||+1&#ffffff0| +0#0000e05#a8a8a8255@1|y+2#0000000#ff404010| +0&#ffd7ff255@20
+| +0#0000e05#a8a8a8255@1|c+0#0000000#ffffff0| @21||+1&&| +0#0000e05#a8a8a8255@1|c+0#0000000#ffffff0| @20||+1&&| +0#0000e05#a8a8a8255@1|c+0#0000000#ffffff0| @20
+|~+0#4040ff13&| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
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+|:+0&&> @73
diff --git a/src/testdir/dumps/Test_diff_overlapped_3.03.dump b/src/testdir/dumps/Test_diff_overlapped_3.03.dump
new file mode 100644
index 0000000000..6c88b3e706
--- /dev/null
+++ b/src/testdir/dumps/Test_diff_overlapped_3.03.dump
@@ -0,0 +1,20 @@
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+|~+0#4040ff13#ffffff0| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
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+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
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+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
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+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
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+|~| @23||+1#0000000&|~+0#4040ff13&| @22||+1#0000000&|~+0#4040ff13&| @22
+|X+3#0000000&|d|i|f|i|l|e|1| @4|1|,|1| @5|A|l@1| |X+1&&|d|i|f|i|l|e|2| @3|1|,|1| @5|A|l@1| |X|d|i|f|i|l|e|3| @3|1|,|1| @5|A|l@1
+|:+0&&> @73
diff --git a/src/testdir/dumps/Test_diff_overlapped_3.04.dump b/src/testdir/dumps/Test_diff_overlapped_3.04.dump
new file mode 100644
index 0000000000..4c20e25137
--- /dev/null
+++ b/src/testdir/dumps/Test_diff_overlapped_3.04.dump
@@ -0,0 +1,20 @@
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new file mode 100644
index 0000000000..b1c48a38c1
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new file mode 100644
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diff --git a/src/testdir/dumps/Test_diff_overlapped_3.07.dump b/src/testdir/dumps/Test_diff_overlapped_3.07.dump
new file mode 100644
index 0000000000..bb339ae2f6
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new file mode 100644
index 0000000000..b50ceb6e53
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new file mode 100644
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new file mode 100644
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