[PATCH v2 0/4] scalar: add --no-maintenance option

These patches add a new --no-maintenance option to the scalar register and scalar clone commands. My motivation is based on setting up Scalar clones in automated environments that set up a repo onto a disk image for use later. If background maintenance runs during later setup steps, then this introduces a variable that is unexpected at minimum and disruptive at worst. The disruption comes in if the automation has steps to run git maintenance run --task=<X> commands but those commands are blocked due to the maintenance.lock file.

Functionally, these leave the default behavior as-is but allow disabling the git maintenance start step when users opt-in to this difference. The idea of Scalar is to recommend the best practices for a typical user, but allowing customization for expert users.

Updates in v2 =============

 * The previous use of toggle_maintenance() in register_dir() would run the
   'git maintenance unregister --force' command. There is a new patch 1 that
   is explicit about whether this should or should not happen and new tests
   are added to verify this behavior in the later patches.
 * A new patch 4 adds the --[no-]maintenance option to scalar reconfigure.

Thanks, -Stolee

Derrick Stolee (4):
  scalar: customize register_dir()'s behavior
  scalar register: add --no-maintenance option
  scalar clone: add --no-maintenance option
  scalar reconfigure: add --no-maintenance option

 Documentation/scalar.adoc | 29 ++++++++++++++++++----
 scalar.c                  | 51 +++++++++++++++++++++++++++++----------
 t/t9210-scalar.sh         | 20 +++++++++++++--
 t/t9211-scalar-clone.sh   | 11 ++++++++-
 4 files changed, 90 insertions(+), 21 deletions(-)

base-commit: f65182a99e545d2f2bc22e6c1c2da192133b16a3
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1913%2Fderrickstolee%2Fscalar-no-maintenance-v2
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1913/derrickstolee/scalar-no-maintenance-v2
Pull-Request: https://github.com/gitgitgadget/git/pull/1913

Range-diff vs v1:

 -:  ----------- > 1:  f3a3cfe3ef1 scalar: customize register_dir()'s behavior
 1:  4910bacd052 ! 2:  1b99a559520 scalar register: add --no-maintenance option
     @@ Documentation/scalar.adoc: Note: when this subcommand is called in a worktree th
       
      
       ## scalar.c ##
     -@@ scalar.c: static int stop_fsmonitor_daemon(void)
     - 	return 0;
     - }
     - 
     --static int register_dir(void)
     -+static int register_dir(int maintenance)
     - {
     - 	if (add_or_remove_enlistment(1))
     - 		return error(_("could not add enlistment"));
     -@@ scalar.c: static int register_dir(void)
     - 	if (set_recommended_config(0))
     - 		return error(_("could not set recommended config"));
     - 
     --	if (toggle_maintenance(1))
     -+	if (toggle_maintenance(maintenance))
     - 		warning(_("could not turn on maintenance"));
     - 
     - 	if (have_fsmonitor_support() && start_fsmonitor_daemon()) {
     -@@ scalar.c: static int cmd_clone(int argc, const char **argv)
     - 	if (res)
     - 		goto cleanup;
     - 
     --	res = register_dir();
     -+	res = register_dir(1);
     - 
     - cleanup:
     - 	free(branch_to_free);
      @@ scalar.c: static int cmd_list(int argc, const char **argv UNUSED)
       
       static int cmd_register(int argc, const char **argv)
     @@ scalar.c: static int cmd_register(int argc, const char **argv)
       
       	setup_enlistment_directory(argc, argv, usage, options, NULL);
       
     --	return register_dir();
     +-	return register_dir(1);
     ++	/* If --no-maintenance, then leave maintenance as-is. */
      +	return register_dir(maintenance);
       }
       
       static int get_scalar_repos(const char *key, const char *value,
     -@@ scalar.c: static int cmd_run(int argc, const char **argv)
     - 	strbuf_release(&buf);
     - 
     - 	if (i == 0)
     --		return register_dir();
     -+		return register_dir(1);
     - 
     - 	if (i > 0)
     - 		return run_git("maintenance", "run",
     - 			       "--task", tasks[i].task, NULL);
     - 
     --	if (register_dir())
     -+	if (register_dir(1))
     - 		return -1;
     - 	for (i = 1; tasks[i].arg; i++)
     - 		if (run_git("maintenance", "run",
      
       ## t/t9210-scalar.sh ##
     +@@ t/t9210-scalar.sh: test_expect_success 'scalar register warns when background maintenance fails' '
     + 	git init register-repo &&
     + 	GIT_TEST_MAINT_SCHEDULER="crontab:false,launchctl:false,schtasks:false" \
     + 		scalar register register-repo 2>err &&
     +-	grep "could not turn on maintenance" err
     ++	grep "could not toggle maintenance" err
     + '
     + 
     + test_expect_success 'scalar unregister' '
      @@ t/t9210-scalar.sh: test_expect_success 'scalar unregister' '
       	scalar unregister vanish
       '
       
      +test_expect_success 'scalar register --no-maintenance' '
      +	git init register-no-maint &&
     ++	event_log="$(pwd)/no-maint.event" &&
      +	GIT_TEST_MAINT_SCHEDULER="crontab:false,launchctl:false,schtasks:false" \
     ++	GIT_TRACE2_EVENT="$event_log" \
     ++	GIT_TRACE2_EVENT_DEPTH=100 \
      +		scalar register --no-maintenance register-no-maint 2>err &&
     -+	test_must_be_empty err
     ++	test_must_be_empty err &&
     ++	test_subcommand ! git maintenance unregister --force <no-maint.event
      +'
      +
       test_expect_success 'set up repository to clone' '
 2:  7ab1914b830 ! 3:  e52b1282d93 scalar clone: add --no-maintenance option
     @@ scalar.c: static int cmd_clone(int argc, const char **argv)
       		goto cleanup;
       
      -	res = register_dir(1);
     ++	/* If --no-maintenance, then skip maintenance command entirely. */
      +	res = register_dir(maintenance);
       
       cleanup:
       	free(branch_to_free);
      
       ## t/t9211-scalar-clone.sh ##
     -@@ t/t9211-scalar-clone.sh: test_expect_success 'scalar clone warns when background maintenance fails' '
     - 	grep "could not turn on maintenance" err
     - '
     - 
     +@@ t/t9211-scalar-clone.sh: test_expect_success 'progress without tty' '
     + test_expect_success 'scalar clone warns when background maintenance fails' '
     + 	GIT_TEST_MAINT_SCHEDULER="crontab:false,launchctl:false,schtasks:false" \
     + 		scalar clone "file://$(pwd)/to-clone" maint-fail 2>err &&
     +-	grep "could not turn on maintenance" err
     ++	grep "could not toggle maintenance" err
     ++'
     ++
      +test_expect_success 'scalar clone --no-maintenance' '
      +	GIT_TEST_MAINT_SCHEDULER="crontab:false,launchctl:false,schtasks:false" \
     ++	GIT_TRACE2_EVENT="$(pwd)/no-maint.event" \
     ++	GIT_TRACE2_EVENT_DEPTH=100 \
      +		scalar clone --no-maintenance "file://$(pwd)/to-clone" no-maint 2>err &&
     -+	! grep "could not turn on maintenance" err
     -+'
     -+
     ++	! grep "could not toggle maintenance" err &&
     ++	test_subcommand ! git maintenance unregister --force <no-maint.event
     + '
     + 
       test_expect_success '`scalar clone --no-src`' '
     - 	scalar clone --src "file://$(pwd)/to-clone" with-src &&
     - 	scalar clone --no-src "file://$(pwd)/to-clone" without-src &&
 -:  ----------- > 4:  6fac9c4c394 scalar reconfigure: add --no-maintenance option