GNU diff is the reference for all of these results.
Prepare tests:
$ echo '[alias]' >> $HGRCPATH
$ echo 'ndiff = diff --nodates' >> $HGRCPATH
$ hg init
$ printf 'hello world\ngoodbye world\n' >foo
$ hg ci -Amfoo -ufoo
adding foo
Test added blank lines:
$ printf '\nhello world\n\ngoodbye world\n\n' >foo
>>> two diffs showing three added lines <<<
$ hg ndiff
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,5 @@
+
hello world
+
goodbye world
+
$ hg ndiff -b
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,5 @@
+
hello world
+
goodbye world
+
>>> no diffs <<<
$ hg ndiff -B
$ hg ndiff -Bb
Test added horizontal space first on a line():
$ printf '\t hello world\ngoodbye world\n' >foo
>>> four diffs showing added space first on the first line <<<
$ hg ndiff
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,2 @@
-hello world
+ hello world
goodbye world
$ hg ndiff -b
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,2 @@
-hello world
+ hello world
goodbye world
$ hg ndiff -B
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,2 @@
-hello world
+ hello world
goodbye world
$ hg ndiff -Bb
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,2 @@
-hello world
+ hello world
goodbye world
Test added horizontal space last on a line:
$ printf 'hello world\t \ngoodbye world\n' >foo
>>> two diffs showing space appended to the first line <<<
$ hg ndiff
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,2 @@
-hello world
+hello world
goodbye world
$ hg ndiff -B
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,2 @@
-hello world
+hello world
goodbye world
>>> no diffs <<<
$ hg ndiff -b
$ hg ndiff -Bb
Test added horizontal space in the middle of a word:
$ printf 'hello world\ngood bye world\n' >foo
>>> four diffs showing space inserted into "goodbye" <<<
$ hg ndiff
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,2 @@
hello world
-goodbye world
+good bye world
$ hg ndiff -B
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,2 @@
hello world
-goodbye world
+good bye world
$ hg ndiff -b
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,2 @@
hello world
-goodbye world
+good bye world
$ hg ndiff -Bb
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,2 @@
hello world
-goodbye world
+good bye world
Test increased horizontal whitespace amount:
$ printf 'hello world\ngoodbye\t\t \tworld\n' >foo
>>> two diffs showing changed whitespace amount in the last line <<<
$ hg ndiff
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,2 @@
hello world
-goodbye world
+goodbye world
$ hg ndiff -B
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,2 @@
hello world
-goodbye world
+goodbye world
>>> no diffs <<<
$ hg ndiff -b
$ hg ndiff -Bb
Test added blank line with horizontal whitespace:
$ printf 'hello world\n \t\ngoodbye world\n' >foo
>>> three diffs showing added blank line with horizontal space <<<
$ hg ndiff
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,3 @@
hello world
+
goodbye world
$ hg ndiff -B
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,3 @@
hello world
+
goodbye world
$ hg ndiff -b
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,3 @@
hello world
+
goodbye world
>>> no diffs <<<
$ hg ndiff -Bb
Test added blank line with other whitespace:
$ printf 'hello world\n \t\ngoodbye world \n' >foo
>>> three diffs showing added blank line with other space <<<
$ hg ndiff
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,3 @@
-hello world
-goodbye world
+hello world
+
+goodbye world
$ hg ndiff -B
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,3 @@
-hello world
-goodbye world
+hello world
+
+goodbye world
$ hg ndiff -b
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,3 @@
hello world
+
goodbye world
>>> no diffs <<<
$ hg ndiff -Bb
Test whitespace changes:
$ printf 'helloworld\ngoodbye\tworld \n' >foo
>>> four diffs showing changed whitespace <<<
$ hg ndiff
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,2 @@
-hello world
-goodbye world
+helloworld
+goodbye world
$ hg ndiff -B
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,2 @@
-hello world
-goodbye world
+helloworld
+goodbye world
$ hg ndiff -b
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,2 @@
-hello world
+helloworld
goodbye world
$ hg ndiff -Bb
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,2 @@
-hello world
+helloworld
goodbye world
>>> no diffs <<<
$ hg ndiff -w
Test whitespace changes and blank lines:
$ printf 'helloworld\n\n\n\ngoodbye\tworld \n' >foo
>>> five diffs showing changed whitespace <<<
$ hg ndiff
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,5 @@
-hello world
-goodbye world
+helloworld
+
+
+
+goodbye world
$ hg ndiff -B
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,5 @@
-hello world
-goodbye world
+helloworld
+
+
+
+goodbye world
$ hg ndiff -b
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,5 @@
-hello world
+helloworld
+
+
+
goodbye world
$ hg ndiff -Bb
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,5 @@
-hello world
+helloworld
+
+
+
goodbye world
$ hg ndiff -w
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,5 @@
hello world
+
+
+
goodbye world
>>> no diffs <<<
$ hg ndiff -wB
Test \r (carriage return) as used in "DOS" line endings:
$ printf 'hello world\r\n\r\ngoodbye\rworld\n' >foo
$ hg ndiff
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,3 @@
-hello world
-goodbye world
+hello world\r (esc)
+\r (esc)
+goodbye\r (no-eol) (esc)
world
No completely blank lines to ignore:
$ hg ndiff --ignore-blank-lines
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,3 @@
-hello world
-goodbye world
+hello world\r (esc)
+\r (esc)
+goodbye\r (no-eol) (esc)
world
Only new line noticed:
$ hg ndiff --ignore-space-change
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,3 @@
hello world
+\r (esc)
goodbye world
$ hg ndiff --ignore-all-space
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,3 @@
hello world
+\r (esc)
goodbye world
New line not noticed when space change ignored:
$ hg ndiff --ignore-blank-lines --ignore-all-space
Do not ignore all newlines, only blank lines
$ printf 'hello \nworld\ngoodbye world\n' > foo
$ hg ndiff --ignore-blank-lines
diff -r 540c40a65b78 foo
--- a/foo
+++ b/foo
@@ -1,2 +1,3 @@
-hello world
+hello
+world
goodbye world
Test hunk offsets adjustments with --ignore-blank-lines
$ hg revert -aC
reverting foo
$ printf '\nb\nx\nd\n' > a
$ printf 'b\ny\nd\n' > b
$ hg add a b
$ hg ci -m add
$ hg cat -r . a > b
$ hg cat -r . b > a
$ hg diff -B --nodates a > ../diffa
$ cat ../diffa
diff -r 0e66aa54f318 a
--- a/a
+++ b/a
@@ -1,4 +1,4 @@
b
-x
+y
d
$ hg diff -B --nodates b > ../diffb
$ cat ../diffb
diff -r 0e66aa54f318 b
--- a/b
+++ b/b
@@ -1,3 +1,3 @@
b
-y
+x
d
$ hg revert -aC
reverting a
reverting b
$ hg import --no-commit ../diffa
applying ../diffa
$ hg revert -aC
reverting a
$ hg import --no-commit ../diffb
applying ../diffb
$ hg revert -aC
reverting b