rebase: rename the two primary rebase backends

Two related changes, with separate rationale for each:

Rename the 'interactive' backend to 'merge' because:
  * 'interactive' as a name caused confusion; this backend has been used
    for many kinds of non-interactive rebases, and will probably be used
    in the future for more non-interactive rebases than interactive ones
    given that we are making it the default.
  * 'interactive' is not the underlying strategy; merging is.
  * the directory where state is stored is not called
    .git/rebase-interactive but .git/rebase-merge.

Rename the 'am' backend to 'apply' because:
  * Few users are familiar with git-am as a reference point.
  * Related to the above, the name 'am' makes sentences in the
    documentation harder for users to read and comprehend (they may read
    it as the verb from "I am"); avoiding this difficult places a large
    burden on anyone writing documentation about this backend to be very
    careful with quoting and sentence structure and often forces
    annoying redundancy to try to avoid such problems.
  * Users stumble over pronunciation ("am" as in "I am a person not a
    backend" or "am" as in "the first and thirteenth letters in the
    alphabet in order are "A-M"); this may drive confusion when one user
    tries to explain to another what they are doing.
  * While "am" is the tool driving this backend, the tool driving git-am
    is git-apply, and since we are driving towards lower-level tools
    for the naming of the merge backend we may as well do so here too.
  * The directory where state is stored has never been called
    .git/rebase-am, it was always called .git/rebase-apply.

For all the reasons listed above:
  * Modify the documentation to refer to the backends with the new names
  * Provide a brief note in the documentation connecting the new names
    to the old names in case users run across the old names anywhere
    (e.g. in old release notes or older versions of the documentation)
  * Change the (new) --am command line flag to --apply
  * Rename some enums, variables, and functions to reinforce the new
    backend names for us as well.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 6 insertions, 6 deletions

diff --git a/t/t7512-status-help.sh b/t/t7512-status-help.sh
index d22b0acf2a..29518e0949 100755
--- a/t/t7512-status-help.sh
+++ b/t/t7512-status-help.sh
@@ -71,10 +71,10 @@ test_expect_success 'prepare for rebase conflicts' '
 '
 
 
-test_expect_success 'status when rebase --am in progress before resolving conflicts' '
+test_expect_success 'status when rebase --apply in progress before resolving conflicts' '
 	test_when_finished "git rebase --abort" &&
 	ONTO=$(git rev-parse --short HEAD^^) &&
-	test_must_fail git rebase --am HEAD^ --onto HEAD^^ &&
+	test_must_fail git rebase --apply HEAD^ --onto HEAD^^ &&
 	cat >expected <<EOF &&
 rebase in progress; onto $ONTO
 You are currently rebasing branch '\''rebase_conflicts'\'' on '\''$ONTO'\''.
@@ -94,11 +94,11 @@ EOF
 '
 
 
-test_expect_success 'status when rebase --am in progress before rebase --continue' '
+test_expect_success 'status when rebase --apply in progress before rebase --continue' '
 	git reset --hard rebase_conflicts &&
 	test_when_finished "git rebase --abort" &&
 	ONTO=$(git rev-parse --short HEAD^^) &&
-	test_must_fail git rebase --am HEAD^ --onto HEAD^^ &&
+	test_must_fail git rebase --apply HEAD^ --onto HEAD^^ &&
 	echo three >main.txt &&
 	git add main.txt &&
 	cat >expected <<EOF &&
@@ -688,7 +688,7 @@ EOF
 '
 
 
-test_expect_success 'status when rebase --am conflicts with statushints disabled' '
+test_expect_success 'status when rebase --apply conflicts with statushints disabled' '
 	git reset --hard master &&
 	git checkout -b statushints_disabled &&
 	test_when_finished "git config --local advice.statushints true" &&
@@ -698,7 +698,7 @@ test_expect_success 'status when rebase --am conflicts with statushints disabled
 	test_commit three_statushints main.txt three &&
 	test_when_finished "git rebase --abort" &&
 	ONTO=$(git rev-parse --short HEAD^^) &&
-	test_must_fail git rebase --am HEAD^ --onto HEAD^^ &&
+	test_must_fail git rebase --apply HEAD^ --onto HEAD^^ &&
 	cat >expected <<EOF &&
 rebase in progress; onto $ONTO
 You are currently rebasing branch '\''statushints_disabled'\'' on '\''$ONTO'\''.