This series enables the built-in FSMonitor [1] on 'scalar'-registered
repository enlistments. To avoid errors when unregistering an enlistment,
the FSMonitor daemon is explicitly stopped during 'scalar unregister'.

Maintainer's note: this series has a minor conflict with
'vd/scalar-generalize-diagnose'. Please let me know if there's anything else
I can provide (in addition to [2]) that would make resolution easier.

Changes since V1
================

 * Added a patch to fix 'unregister_dir()'s handling of return values > 0
   from 'toggle_maintenance()' and 'add_or_remove_enlistment()'.
 * Added a patch to print error messages in 'register_dir()' and
   'unregister_dir()' indicating which of their internal steps fail.
 * Moved check of 'fsmonitor_ipc__is_supported()' to '[un]register_dir()' to
   avoid calling '(start|stop)_fsmonitor_daemon()' when the feature is not
   supported. Added assertion of 'fsmonitor_ipc__is_supported()' to
   '(start|stop)_fsmonitor_daemon()' to enforce that they are not called
   when the feature is unavailable.
 * Simplified '(start|stop)_fsmonitor_daemon()' implementation. Now, if
   FSMonitor is already running/stopped (respectively), the function simply
   returns 0; otherwise, it runs 'git fsmonitor--daemon (start|stop)' and
   returns the exit code.
   * Note that the "could not (start|stop) the FSMonitor daemon: <err_msg>"
     error messages are no longer printed by
     '(start|stop)_fsmonitor_daemon()'. Instead, "<err_msg>" is printed to
     stderr by swapping 'pipe_command()' out for 'run_git()', and
     '[un]register_dir()' prints the "could not (start|stop) the FSMonitor
     daemon" message.

Thanks

 * Victoria

[1]
https://lore.kernel.org/git/pull.1143.git.1644940773.gitgitgadget@gmail.com/

[2] The conflict is a result of both series updating the Scalar roadmap doc.
For reference, my merge resolution (from git diff <merge commit> <merge
commit>^1 <merge commit>^2, where <merge commit>^1 is
'vd/scalar-generalize-diagnose' and <merge commit>^2 is this series) looks
like:

------------->8------------->8------------->8------------->8------------->8-------------
diff --cc Documentation/technical/scalar.txt
index f6353375f0,047390e46e..0600150b3a
--- a/Documentation/technical/scalar.txt
+++ b/Documentation/technical/scalar.txt
@@@ -84,20 -84,26 +84,23 @@@ series have been accepted

  - `scalar-diagnose`: The `scalar` command is taught the `diagnose` subcommand.

 +- `scalar-generalize-diagnose`: Move the functionality of `scalar diagnose`
 +  into `git diagnose` and `git bugreport --diagnose`.
 +
+ - 'scalar-add-fsmonitor: Enable the built-in FSMonitor in Scalar
+   enlistments. At the end of this series, Scalar should be feature-complete
+   from the perspective of a user.
+
  Roughly speaking (and subject to change), the following series are needed to
  "finish" this initial version of Scalar:

- - Finish Scalar features: Enable the built-in FSMonitor in Scalar enlistments
-   and implement `scalar help`. At the end of this series, Scalar should be
-   feature-complete from the perspective of a user.
 -- Generalize features not specific to Scalar: In the spirit of making Scalar
 -  configure only what is needed for large repo performance, move common
 -  utilities into other parts of Git. Some of this will be internal-only, but one
 -  major change will be generalizing `scalar diagnose` for use with any Git
 -  repository.
--
  - Move Scalar to toplevel: Move Scalar out of `contrib/` and into the root of
-   `git`, including updates to build and install it with the rest of Git. This
-   change will incorporate Scalar into the Git CI and test framework, as well as
-   expand regression and performance testing to ensure the tool is stable.
+   `git`. This includes a variety of related updates, including:
+     - building & installing Scalar in the Git root-level 'make [install]'.
+     - builing & testing Scalar as part of CI.
+     - moving and expanding test coverage of Scalar (including perf tests).
+     - implementing 'scalar help'/'git help scalar' to display scalar
+       documentation.

  Finally, there are two additional patch series that exist in Microsoft's fork of
  Git, but there is no current plan to upstream them. There are some interesting
-------------8<-------------8<-------------8<-------------8<-------------8<---------

Johannes Schindelin (1):
  scalar unregister: stop FSMonitor daemon

Matthew John Cheetham (1):
  scalar: enable built-in FSMonitor on `register`

Victoria Dye (3):
  scalar-unregister: handle error codes greater than 0
  scalar-[un]register: clearly indicate source of error
  scalar: update technical doc roadmap with FSMonitor support

 Documentation/technical/scalar.txt | 17 +++++----
 contrib/scalar/scalar.c            | 55 ++++++++++++++++++++++++------
 contrib/scalar/t/t9099-scalar.sh   | 11 ++++++
 3 files changed, 66 insertions(+), 17 deletions(-)

base-commit: 4af7188bc97f70277d0f10d56d5373022b1fa385

Submitted-As: https://lore.kernel.org/git/pull.1324.v2.git.1660694290.gitgitgadget@gmail.com
In-Reply-To: https://lore.kernel.org/git/pull.1324.git.1660673269.gitgitgadget@gmail.com