This fixes a bug where even if `merge.conflictStyle = diff3`, running `git apply --3way` would not output the base.

Patches 1-3 are general cleanup for t4108, 4 demonstrates the bug and 5 actually fixes it.

Changes since v1:

* Pretty up 4/5 using Eric's suggestion

* Rename print_sanitized_diff() to print_santized_conflicted_diff()

Denton Liu (5):
t4108: replace create_file with test_write_lines
t4108: remove git command upstream of pipe
t4108: use test_config instead of git config
t4108: demonstrate bug in apply
apply: respect merge.conflictStyle in --3way

 apply.c                   |  2 +-
 t/t4108-apply-threeway.sh | 55 +++++++++++++++++++++------------------
 2 files changed, 30 insertions(+), 27 deletions(-)

Range-diff against v1:
1: 9d915748c1 ! 1: fd1b770c0c t4108: remove git command upstream of pipe

    @@ Commit message
     
         Since only the command `git diff HEAD` was being piped to
         sanitize_conflicted_diff(), move the command into the function and rename
    -    it to print_sanitized_diff().
    +    it to print_sanitized_conflicted_diff().
     
      ## t/t4108-apply-threeway.sh ##
     @@ t/t4108-apply-threeway.sh: test_description='git apply --3way'
    @@ t/t4108-apply-threeway.sh: test_description='git apply --3way'
      . ./test-lib.sh
      
     -sanitize_conflicted_diff () {
    -+print_sanitized_diff () {
    ++print_sanitized_conflicted_diff () {
     +	git diff HEAD >diff.raw &&
      	sed -e '
      		/^index /d
    @@ t/t4108-apply-threeway.sh: test_expect_success 'apply with --3way' '
      	test_must_fail git merge --no-commit side &&
      	git ls-files -s >expect.ls &&
     -	git diff HEAD | sanitize_conflicted_diff >expect.diff &&
    -+	print_sanitized_diff >expect.diff &&
    ++	print_sanitized_conflicted_diff >expect.diff &&
      
      	# should fail to apply
      	git reset --hard &&
    @@ t/t4108-apply-threeway.sh: test_expect_success 'apply with --3way' '
      	test_must_fail git apply --index --3way P.diff &&
      	git ls-files -s >actual.ls &&
     -	git diff HEAD | sanitize_conflicted_diff >actual.diff &&
    -+	print_sanitized_diff >actual.diff &&
    ++	print_sanitized_conflicted_diff >actual.diff &&
      
      	# The result should resemble the corresponding merge
      	test_cmp expect.ls actual.ls &&
    @@ t/t4108-apply-threeway.sh: test_expect_success 'apply -3 with add/add conflict s
      	test_must_fail git merge --no-commit another &&
      	git ls-files -s >expect.ls &&
     -	git diff HEAD | sanitize_conflicted_diff >expect.diff
    -+	print_sanitized_diff >expect.diff
    ++	print_sanitized_conflicted_diff >expect.diff
      '
      
      test_expect_success 'apply -3 with add/add conflict' '
    @@ t/t4108-apply-threeway.sh: test_expect_success 'apply -3 with add/add conflict'
      	# ... and leave conflicts in the index and in the working tree
      	git ls-files -s >actual.ls &&
     -	git diff HEAD | sanitize_conflicted_diff >actual.diff &&
    -+	print_sanitized_diff >actual.diff &&
    ++	print_sanitized_conflicted_diff >actual.diff &&
      
      	# The result should resemble the corresponding merge
      	test_cmp expect.ls actual.ls &&
2:  d77c5f4199 = 2:  43c42b299e t4108: use `test_config` instead of `git config`
3:  5feddf1597 < -:  ---------- t4108: demonstrate bug in apply
-:  ---------- > 3:  58d32e2618 t4108: demonstrate bug in apply
4:  56c31310db ! 4:  5412dc9153 apply: respect merge.conflictStyle in --3way

@@ apply.c: static void git_apply_config(void)
static int parse_whitespace_option(struct apply_state *state, const char *option)

## t/t4108-apply-threeway.sh ##
-@@ t/t4108-apply-threeway.sh: test_apply_with_3way () {
- }
+@@ t/t4108-apply-threeway.sh: test_expect_success 'apply with --3way' '
+ test_apply_with_3way
+ '

- test_apply_with_3way success default true
--test_apply_with_3way failure 'merge.conflictStyle = diff3' 'test_config merge.conflictStyle diff3' -+test_apply_with_3way success 'merge.conflictStyle = diff3' 'test_config merge.conflictStyle diff3' -
- test_expect_success 'apply with --3way with rerere enabled' '
- test_config rerere.enabled true &&
+-test_expect_failure 'apply with --3way with merge.conflictStyle = diff3' ' ++test_expect_success 'apply with --3way with merge.conflictStyle = diff3' '
+ test_config merge.conflictStyle diff3 &&
+ test_apply_with_3way
+ '

2.24.0.rc0.197.g0926ab8072