mbox series

[v2,0/9] sparse-checkout: make cone mode the default

Message ID pull.1148.v2.git.1647054681.gitgitgadget@gmail.com (mailing list archive)
Headers show
Series sparse-checkout: make cone mode the default | expand

Message

Johannes Schindelin via GitGitGadget March 12, 2022, 3:11 a.m. UTC
== Updates Log ==

Changes since v1:

 * rebased on master, to remove dependence on en/present-despite-skipped
   (which has since merged to master). Earlier version of series wasn't
   picked up anyway, so rebasing should be safe.
 * Wording and code style tweaks suggested by Stolee in his review

== Overview ==

This patch changes the default mode for sparse-checkout from non-cone mode
to cone-mode, and marks non-cone mode as deprecated. There is no plan to
remove non-cone mode, we are merely recommending against its use.

The code change is pretty small, and most of this series is about
documentation updates -- to focus on directories rather than patterns, to
explain the new default, to explain why we are deprecating non-cone mode
(the final patch), and to make other related cleanups to simplify the
manual.

Patch 1: Update tests to not assume cone-mode is the default Patch 2: Make
cone-mode the default Patches 3-9: Various updates to
git-sparse-checkout.txt, divided up for ease of review

== Alternative ==

There is one primary alternative to this series: make sparse-checkout error
when neither --cone nor --no-cone are specified (so that there is no
default), and wait until a future date to make --cone the default. That'd be
reasonable, but I had three reason to avoid going this route (note that item
2 means there's little practical difference between cone-mode-as-default and
no-mode-is-default):

 1. git-sparse-checkout.txt has the following huge warning early in the
    manual:

""" THIS COMMAND IS EXPERIMENTAL. ITS BEHAVIOR, AND THE BEHAVIOR OF OTHER
COMMANDS IN THE PRESENCE OF SPARSE-CHECKOUTS, WILL LIKELY CHANGE IN THE
FUTURE. """

 2. If users are unaware of the default change and attempt to provide
    patterns instead of directories, then they will get error messages added
    from en/sparse-checkout-fixes. They can learn at that time to get around
    the error messages by providing --no-cone.

 3. If users are unaware of the default change and provide directories, then
    that's where non-cone mode and cone mode overlap and things happen to
    work. (There is a slight difference in that cone mode will include files
    from parent directories of any specified directory, but that means the
    user gets a few more files in their sparse-checkout with cone mode than
    they would with non-cone mode.)

== CCs ==

Elijah Newren (9):
  tests: stop assuming --no-cone is the default mode for sparse-checkout
  sparse-checkout: make --cone the default
  git-sparse-checkout.txt: wording updates for the cone mode default
  git-sparse-checkout.txt: update docs for deprecation of 'init'
  git-sparse-checkout.txt: shuffle some sections and mark as internal
  git-sparse-checkout.txt: add a new EXAMPLES section
  git-sparse-checkout.txt: flesh out non-cone mode pattern discussion a
    bit
  git-sparse-checkout.txt: mark non-cone mode as deprecated
  Documentation: some sparsity wording clarifications

 Documentation/git-read-tree.txt       |   9 +-
 Documentation/git-sparse-checkout.txt | 249 +++++++++++++++++++-------
 builtin/sparse-checkout.c             |   2 +-
 t/t1091-sparse-checkout-builtin.sh    |  15 +-
 t/t3602-rm-sparse-checkout.sh         |   6 +-
 t/t3705-add-sparse-checkout.sh        |   4 +-
 t/t6428-merge-conflicts-sparse.sh     |   4 +-
 t/t7002-mv-sparse-checkout.sh         |   2 +-
 t/t7012-skip-worktree-writing.sh      |   2 +-
 9 files changed, 207 insertions(+), 86 deletions(-)


base-commit: 1a4874565fa3b6668042216189551b98b4dc0b1b
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1148%2Fnewren%2Fsparse-checkout-default-v2
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1148/newren/sparse-checkout-default-v2
Pull-Request: https://github.com/gitgitgadget/git/pull/1148

Range-diff vs v1:

  1:  8c3e730e86b =  1:  05dba7069c5 tests: stop assuming --no-cone is the default mode for sparse-checkout
  2:  b174b42ed82 !  2:  a53179764bc sparse-checkout: make --cone the default
     @@ builtin/sparse-checkout.c: static int update_modes(int *cone_mode, int *sparse_i
       	/* Set cone/non-cone mode appropriately */
       	core_apply_sparse_checkout = 1;
      -	if (*cone_mode == 1) {
     -+	if (*cone_mode == 1 || *cone_mode == -1) {
     ++	if (*cone_mode) { /* also handles "not specified" (value of -1) */
       		mode = MODE_CONE_PATTERNS;
       		core_sparse_checkout_cone = 1;
       	} else {
  3:  f98b3fac78a =  3:  8eab21996c7 git-sparse-checkout.txt: wording updates for the cone mode default
  4:  cd871966c06 =  4:  eb3b318b39e git-sparse-checkout.txt: update docs for deprecation of 'init'
  5:  fe37a966699 =  5:  7333198b778 git-sparse-checkout.txt: shuffle some sections and mark as internal
  6:  3265f41bcab !  6:  a814ea9e8d2 git-sparse-checkout.txt: add a new EXAMPLES section
     @@ Documentation/git-sparse-checkout.txt: paths to pass to a subsequent 'set' or 'a
      +
      +`git sparse-checkout reapply`::
      +
     -+	It is possible for commands to update the working tree in a way
     -+	that does not respect the selected sparsity directories, either
     -+	because of special cases (such as hitting conflicts when
     -+	merging/rebasing), or because some commands didn't fully support
     -+	sparse checkouts (e.g. the old `recursive` merge backend had
     -+	only limited support).  This command reapplies the existing
     -+	sparse directory specifications to make the working directory
     -+	match.
     ++	It is possible for commands to update the working tree in a
     ++	way that does not respect the selected sparsity directories.
     ++	This can come from tools external to Git writing files, or
     ++	even affect Git commands because of either special cases (such
     ++	as hitting conflicts when merging/rebasing), or because some
     ++	commands didn't fully support sparse checkouts (e.g. the old
     ++	`recursive` merge backend had only limited support).  This
     ++	command reapplies the existing sparse directory specifications
     ++	to make the working directory match.
      +
       INTERNALS -- SPARSE CHECKOUT
       ----------------------------
  7:  bdbf61ee6a0 =  7:  78028ecaa58 git-sparse-checkout.txt: flesh out non-cone mode pattern discussion a bit
  8:  3e35d62c5ee =  8:  2d2b81986a5 git-sparse-checkout.txt: mark non-cone mode as deprecated
  9:  e7d3ff70914 =  9:  4b89a3392b0 Documentation: some sparsity wording clarifications

Comments

Derrick Stolee March 14, 2022, 3:25 p.m. UTC | #1
On 3/11/2022 10:11 PM, Elijah Newren via GitGitGadget wrote:
> == Updates Log ==
> 
> Changes since v1:
> 
>  * rebased on master, to remove dependence on en/present-despite-skipped
>    (which has since merged to master). Earlier version of series wasn't
>    picked up anyway, so rebasing should be safe.
>  * Wording and code style tweaks suggested by Stolee in his review

Thanks for these updates. This version looks good to me.

Thanks,
-Stolee
Victoria Dye March 14, 2022, 7:04 p.m. UTC | #2
Elijah Newren via GitGitGadget wrote:
> == Updates Log ==
> 
> Changes since v1:
> 
>  * rebased on master, to remove dependence on en/present-despite-skipped
>    (which has since merged to master). Earlier version of series wasn't
>    picked up anyway, so rebasing should be safe.
>  * Wording and code style tweaks suggested by Stolee in his review
> 
> == Overview ==
> 
> This patch changes the default mode for sparse-checkout from non-cone mode
> to cone-mode, and marks non-cone mode as deprecated. There is no plan to
> remove non-cone mode, we are merely recommending against its use.
> 
> The code change is pretty small, and most of this series is about
> documentation updates -- to focus on directories rather than patterns, to
> explain the new default, to explain why we are deprecating non-cone mode
> (the final patch), and to make other related cleanups to simplify the
> manual.
> 
> Patch 1: Update tests to not assume cone-mode is the default Patch 2: Make
> cone-mode the default Patches 3-9: Various updates to
> git-sparse-checkout.txt, divided up for ease of review
> 

After looking over the patches (and Stolee's prior feedback), I don't have
any additional comments - it all looks great! 

I also ran through some scenarios going from "non-cone" to "cone mode" that
have been buggy in the past (e.g., non-cone directory patterns missing a
leading '/', then 'git sparse-checkout init --cone'), but it looks like the
checks added back in a3eca58445 (sparse-checkout: refuse to add to bad
patterns, 2021-12-16) prevent any unexplained behavior for a user that might
not be aware of the new default. In other words, changing the default looks
to be safe and overall pushes users towards a better experience using
sparse-checkout.

> == Alternative ==
> 
> There is one primary alternative to this series: make sparse-checkout error
> when neither --cone nor --no-cone are specified (so that there is no
> default), and wait until a future date to make --cone the default. That'd be
> reasonable, but I had three reason to avoid going this route (note that item
> 2 means there's little practical difference between cone-mode-as-default and
> no-mode-is-default):
> 
>  1. git-sparse-checkout.txt has the following huge warning early in the
>     manual:
> 
> """ THIS COMMAND IS EXPERIMENTAL. ITS BEHAVIOR, AND THE BEHAVIOR OF OTHER
> COMMANDS IN THE PRESENCE OF SPARSE-CHECKOUTS, WILL LIKELY CHANGE IN THE
> FUTURE. """
> 
>  2. If users are unaware of the default change and attempt to provide
>     patterns instead of directories, then they will get error messages added
>     from en/sparse-checkout-fixes. They can learn at that time to get around
>     the error messages by providing --no-cone.
> 
>  3. If users are unaware of the default change and provide directories, then
>     that's where non-cone mode and cone mode overlap and things happen to
>     work. (There is a slight difference in that cone mode will include files
>     from parent directories of any specified directory, but that means the
>     user gets a few more files in their sparse-checkout with cone mode than
>     they would with non-cone mode.)
> 

Agreed with your comments here and Stolee's earlier that changing the
default is a better approach.

> == CCs ==
> 
> Elijah Newren (9):
>   tests: stop assuming --no-cone is the default mode for sparse-checkout
>   sparse-checkout: make --cone the default
>   git-sparse-checkout.txt: wording updates for the cone mode default
>   git-sparse-checkout.txt: update docs for deprecation of 'init'
>   git-sparse-checkout.txt: shuffle some sections and mark as internal
>   git-sparse-checkout.txt: add a new EXAMPLES section
>   git-sparse-checkout.txt: flesh out non-cone mode pattern discussion a
>     bit
>   git-sparse-checkout.txt: mark non-cone mode as deprecated
>   Documentation: some sparsity wording clarifications
> 
>  Documentation/git-read-tree.txt       |   9 +-
>  Documentation/git-sparse-checkout.txt | 249 +++++++++++++++++++-------
>  builtin/sparse-checkout.c             |   2 +-
>  t/t1091-sparse-checkout-builtin.sh    |  15 +-
>  t/t3602-rm-sparse-checkout.sh         |   6 +-
>  t/t3705-add-sparse-checkout.sh        |   4 +-
>  t/t6428-merge-conflicts-sparse.sh     |   4 +-
>  t/t7002-mv-sparse-checkout.sh         |   2 +-
>  t/t7012-skip-worktree-writing.sh      |   2 +-
>  9 files changed, 207 insertions(+), 86 deletions(-)
> 
> 
> base-commit: 1a4874565fa3b6668042216189551b98b4dc0b1b
> Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1148%2Fnewren%2Fsparse-checkout-default-v2
> Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1148/newren/sparse-checkout-default-v2
> Pull-Request: https://github.com/gitgitgadget/git/pull/1148
> 
> Range-diff vs v1:
> 
>   1:  8c3e730e86b =  1:  05dba7069c5 tests: stop assuming --no-cone is the default mode for sparse-checkout
>   2:  b174b42ed82 !  2:  a53179764bc sparse-checkout: make --cone the default
>      @@ builtin/sparse-checkout.c: static int update_modes(int *cone_mode, int *sparse_i
>        	/* Set cone/non-cone mode appropriately */
>        	core_apply_sparse_checkout = 1;
>       -	if (*cone_mode == 1) {
>      -+	if (*cone_mode == 1 || *cone_mode == -1) {
>      ++	if (*cone_mode) { /* also handles "not specified" (value of -1) */
>        		mode = MODE_CONE_PATTERNS;
>        		core_sparse_checkout_cone = 1;
>        	} else {
>   3:  f98b3fac78a =  3:  8eab21996c7 git-sparse-checkout.txt: wording updates for the cone mode default
>   4:  cd871966c06 =  4:  eb3b318b39e git-sparse-checkout.txt: update docs for deprecation of 'init'
>   5:  fe37a966699 =  5:  7333198b778 git-sparse-checkout.txt: shuffle some sections and mark as internal
>   6:  3265f41bcab !  6:  a814ea9e8d2 git-sparse-checkout.txt: add a new EXAMPLES section
>      @@ Documentation/git-sparse-checkout.txt: paths to pass to a subsequent 'set' or 'a
>       +
>       +`git sparse-checkout reapply`::
>       +
>      -+	It is possible for commands to update the working tree in a way
>      -+	that does not respect the selected sparsity directories, either
>      -+	because of special cases (such as hitting conflicts when
>      -+	merging/rebasing), or because some commands didn't fully support
>      -+	sparse checkouts (e.g. the old `recursive` merge backend had
>      -+	only limited support).  This command reapplies the existing
>      -+	sparse directory specifications to make the working directory
>      -+	match.
>      ++	It is possible for commands to update the working tree in a
>      ++	way that does not respect the selected sparsity directories.
>      ++	This can come from tools external to Git writing files, or
>      ++	even affect Git commands because of either special cases (such
>      ++	as hitting conflicts when merging/rebasing), or because some
>      ++	commands didn't fully support sparse checkouts (e.g. the old
>      ++	`recursive` merge backend had only limited support).  This
>      ++	command reapplies the existing sparse directory specifications
>      ++	to make the working directory match.
>       +
>        INTERNALS -- SPARSE CHECKOUT
>        ----------------------------
>   7:  bdbf61ee6a0 =  7:  78028ecaa58 git-sparse-checkout.txt: flesh out non-cone mode pattern discussion a bit
>   8:  3e35d62c5ee =  8:  2d2b81986a5 git-sparse-checkout.txt: mark non-cone mode as deprecated
>   9:  e7d3ff70914 =  9:  4b89a3392b0 Documentation: some sparsity wording clarifications
>
Junio C Hamano March 14, 2022, 8:12 p.m. UTC | #3
"Elijah Newren via GitGitGadget" <gitgitgadget@gmail.com> writes:

> == Updates Log ==
>
> Changes since v1:
>
>  * rebased on master, to remove dependence on en/present-despite-skipped
>    (which has since merged to master). Earlier version of series wasn't
>    picked up anyway, so rebasing should be safe.
>  * Wording and code style tweaks suggested by Stolee in his review
>
> == Overview ==
>
> This patch changes the default mode for sparse-checkout from non-cone mode
> to cone-mode, and marks non-cone mode as deprecated. There is no plan to
> remove non-cone mode, we are merely recommending against its use.

Hopefully there are some convincing explanation to help users
understand why the cone mode is recommended in the documentation in
these patches.  Was there a discussion on list to give our unanimous
support for this plan, or is this only preference by a developer or
two who have worked on the sparse-checkout code recently?
Junio C Hamano March 14, 2022, 11:19 p.m. UTC | #4
Junio C Hamano <gitster@pobox.com> writes:

> "Elijah Newren via GitGitGadget" <gitgitgadget@gmail.com> writes:
>
>> == Updates Log ==
>>
>> Changes since v1:
>>
>>  * rebased on master, to remove dependence on en/present-despite-skipped
>>    (which has since merged to master). Earlier version of series wasn't
>>    picked up anyway, so rebasing should be safe.
>>  * Wording and code style tweaks suggested by Stolee in his review
>>
>> == Overview ==
>>
>> This patch changes the default mode for sparse-checkout from non-cone mode
>> to cone-mode, and marks non-cone mode as deprecated. There is no plan to
>> remove non-cone mode, we are merely recommending against its use.
>
> Hopefully there are some convincing explanation to help users
> understand why the cone mode is recommended in the documentation in
> these patches.  Was there a discussion on list to give our unanimous
> support for this plan, or is this only preference by a developer or
> two who have worked on the sparse-checkout code recently?

OK.  There are a few things that I found questionable, but they were
mostly documentation issues (and lack of updates to two places, one
in read-tree and the other in config/core.txt).

Thanks.