t4211: fix broken test when one -L range is subset of another

t4211 attempts to test multiple git-log -L ranges where one range is a
superset of the other, and falsely succeeds because its "expected"
output is incorrect.

Overlapping -L ranges handed to git-log are coalesced by
line-log.c:sort_and_merge_range_set() into a set of non-overlapping,
disjoint ranges. When one range is a subset of another,
sort_and_merge_range_set() should coalesce both ranges to the superset
range, but instead the coalesced range often is incorrectly truncated to
the end of the subset range. For example, ranges 2-8 and 3-4 are
coalesced incorrectly to 2-4.

One can observe this incorrect behavior with git-log -L using the test
repository created by t4211. The superset/subset ranges t4211 employs
are 4-$ and 8-12 (where $ represents end-of-file). The coalesced range
should be 4-$. Manually invoking git-log with the same ranges the test
employs, we see:

  % git log -L 4:a.c simple |
    awk '/^commit [0-9a-f]{40}/ { print substr($2,1,7) }'
  4659538
  100b61a
  39b6eb2
  a6eb826
  f04fb20
  de4c48a

  % git log -L 8,12:a.c simple | awk ...
  f04fb20
  de4c48a

  % git log -L 4:a.c -L 8,12:a.c simple | awk ...
  a6eb826
  f04fb20
  de4c48a

This last output is incorrect. 8-12 is a subset of 4-$, hence the output
of the coalesced range should be the same as the 4-$ output shown first.
In fact, the above incorrect output is the truncated bogus range 4-12:

  % git log -L 4,12:a.c simple | awk ...
  a6eb826
  f04fb20
  de4c48a

Fix the test to correctly fail in the presence of the
sort_and_merge_range_set() coalescing bug. Do so by changing the
"expected" output to the commits mentioned in the 4-$ output above.

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/t/t4211-line-log.sh b/t/t4211-line-log.sh
index 7776f93e3d..549df9e054 100755
--- a/t/t4211-line-log.sh
+++ b/t/t4211-line-log.sh
@@ -50,8 +50,8 @@ canned_test "-M -L ':f:b.c' parallel-change" parallel-change-f-to-main
 canned_test "-L 4,12:a.c -L :main:a.c simple" multiple
 canned_test "-L 4,18:a.c -L :main:a.c simple" multiple-overlapping
 canned_test "-L :main:a.c -L 4,18:a.c simple" multiple-overlapping
-canned_test "-L 4:a.c -L 8,12:a.c simple" multiple-superset
-canned_test "-L 8,12:a.c -L 4:a.c simple" multiple-superset
+canned_test_failure "-L 4:a.c -L 8,12:a.c simple" multiple-superset
+canned_test_failure "-L 8,12:a.c -L 4:a.c simple" multiple-superset
 
 test_bad_opts "-L" "switch.*requires a value"
 test_bad_opts "-L b.c" "argument.*not of the form"