Allow combined diff to ignore white-spaces

The combined diff --cc output does not honor options to ignore
whitespace changes (-b, -w, and --ignore-space-at-eol).

Correct this by passing diff flags to diff engine, so that combined
diff behaves as normal diff does with spaces, and by coalescing
lines that are removed from both (or more) parents, honoring the
same rule to ignore whitespace changes.

With this change, a conflict-less merge done using a ignore-*
strategy option will not show any conflict if shown in combined-diff
using the same option.

Signed-off-by: Antoine Pelisse <apelisse@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 111 insertions, 0 deletions

diff --git a/t/t4038-diff-combined.sh b/t/t4038-diff-combined.sh
index 614425ada..b7e16a784 100755
--- a/t/t4038-diff-combined.sh
+++ b/t/t4038-diff-combined.sh
@@ -3,6 +3,7 @@
 test_description='combined diff'
 
 . ./test-lib.sh
+. "$TEST_DIRECTORY"/diff-lib.sh
 
 setup_helper () {
 	one=$1 branch=$2 side=$3 &&
@@ -113,4 +114,114 @@ test_expect_success 'check --cc --raw with forty trees' '
 	grep "^::::::::::::::::::::::::::::::::::::::::[^:]" out
 '
 
+test_expect_success 'setup combined ignore spaces' '
+	git checkout master &&
+	>test &&
+	git add test &&
+	git commit -m initial &&
+
+	tr -d Q <<-\EOF >test &&
+	always coalesce
+	eol space coalesce Q
+	space  change coalesce
+	all spa ces coalesce
+	eol spaces Q
+	space  change
+	all spa ces
+	EOF
+	git commit -m "test space change" -a &&
+
+	git checkout -b side HEAD^ &&
+	tr -d Q <<-\EOF >test &&
+	always coalesce
+	eol space coalesce
+	space change coalesce
+	all spaces coalesce
+	eol spaces
+	space change
+	all spaces
+	EOF
+	git commit -m "test other space changes" -a &&
+
+	test_must_fail git merge master &&
+	tr -d Q <<-\EOF >test &&
+	eol spaces Q
+	space  change
+	all spa ces
+	EOF
+	git commit -m merged -a
+'
+
+test_expect_success 'check combined output (no ignore space)' '
+	git show >actual.tmp &&
+	sed -e "1,/^@@@/d" < actual.tmp >actual &&
+	tr -d Q <<-\EOF >expected &&
+	--always coalesce
+	- eol space coalesce
+	- space change coalesce
+	- all spaces coalesce
+	- eol spaces
+	- space change
+	- all spaces
+	 -eol space coalesce Q
+	 -space  change coalesce
+	 -all spa ces coalesce
+	+ eol spaces Q
+	+ space  change
+	+ all spa ces
+	EOF
+	compare_diff_patch expected actual
+'
+
+test_expect_success 'check combined output (ignore space at eol)' '
+	git show --ignore-space-at-eol >actual.tmp &&
+	sed -e "1,/^@@@/d" < actual.tmp >actual &&
+	tr -d Q <<-\EOF >expected &&
+	--always coalesce
+	--eol space coalesce
+	- space change coalesce
+	- all spaces coalesce
+	 -space  change coalesce
+	 -all spa ces coalesce
+	  eol spaces Q
+	- space change
+	- all spaces
+	+ space  change
+	+ all spa ces
+	EOF
+	compare_diff_patch expected actual
+'
+
+test_expect_success 'check combined output (ignore space change)' '
+	git show -b >actual.tmp &&
+	sed -e "1,/^@@@/d" < actual.tmp >actual &&
+	tr -d Q <<-\EOF >expected &&
+	--always coalesce
+	--eol space coalesce
+	--space change coalesce
+	- all spaces coalesce
+	 -all spa ces coalesce
+	  eol spaces Q
+	  space  change
+	- all spaces
+	+ all spa ces
+	EOF
+	compare_diff_patch expected actual
+'
+
+test_expect_success 'check combined output (ignore all spaces)' '
+	git show -w >actual.tmp &&
+	sed -e "1,/^@@@/d" < actual.tmp >actual &&
+	tr -d Q <<-\EOF >expected &&
+	--always coalesce
+	--eol space coalesce
+	--space change coalesce
+	--all spaces coalesce
+	  eol spaces Q
+	  space  change
+	  all spa ces
+	EOF
+	compare_diff_patch expected actual
+'
+
 test_done