[PATCH v2] docs: fix repository-layout when building with breaking changes

From: Phillip Wood <phillip.wood@dunelm.org.uk>

Since commit 8ccc75c2452 (remote: announce removal of "branches/" and "remotes/", 2025-01-22) enabling WITH_BREAKING_CHANGES when building git removes support for reading branches from ".git/branches" and remotes from ".git/remotes". However those locations are still documented in gitrepository-layout.adoc even though the build does not support them.

Rectify this by adding a new document attribute "with-breaking-changes" and use it to make the inclusion of those sections of the documentation conditional. Note that the name of the attribute does not match the test prerequisite WITHOUT_BREAKING_CHANGES added in c5bc9a7f94a (Makefile: wire up build option for deprecated features, 2025-01-22). This is to avoid the awkward double negative ifndef::without_breaking_changes for documentation that should be included when WITH_BREAKING_CHANGES is enabled. The test prerequisite will be renamed to match the documentation attribute in a future patch series.

Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
---
    docs: fix repository-layout when building with breaking changes
    
    Thanks to Junio and Patrick for their comments on V1. I've renamed the
    attribute to with-breaking-changes as suggested. I'll add a patch to
    rename the test prerequisite to match this when I re-roll
    https://lore.kernel.org/git/pull.1863.git.1740149837.gitgitgadget@gmail.com/
    to use WITH_BREAKING_CHANGES.

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1871%2Fphillipwood%2Fbreaking-changes-documentation-v2
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1871/phillipwood/breaking-changes-documentation-v2
Pull-Request: https://github.com/gitgitgadget/git/pull/1871

Range-diff vs v1:

 1:  42877011c6d ! 1:  d8dcdca4c2b docs: fix repository-layout when building with breaking changes
     @@ Commit message
          from ".git/remotes". However those locations are still documented in
          gitrepository-layout.adoc even though the build does not support them.
      
     -    Rectify this by adding a new document attribute
     -    "without-breaking-changes" and use it to make the inclusion of those
     -    sections of the documentation conditional. The name of the attribute is
     -    based on the similar test prerequisite added in c5bc9a7f94a (Makefile:
     -    wire up build option for deprecated features, 2025-01-22).
     +    Rectify this by adding a new document attribute "with-breaking-changes"
     +    and use it to make the inclusion of those sections of the documentation
     +    conditional. Note that the name of the attribute does not match the test
     +    prerequisite WITHOUT_BREAKING_CHANGES added in c5bc9a7f94a (Makefile:
     +    wire up build option for deprecated features, 2025-01-22). This is to
     +    avoid the awkward double negative ifndef::without_breaking_changes for
     +    documentation that should be included when WITH_BREAKING_CHANGES is
     +    enabled. The test prerequisite will be renamed to match the
     +    documentation attribute in a future patch series.
      
          Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
      
     @@ Documentation/Makefile: asciidoc.conf: asciidoc.conf.in FORCE
       	$(QUIET_GEN)$(call version_gen,"$(shell pwd)/..",$<,$@)
       endif
       
     -+ifndef WITH_BREAKING_CHANGES
     -+ASCIIDOC_EXTRA += -awithout-breaking-changes
     ++ifdef WITH_BREAKING_CHANGES
     ++ASCIIDOC_EXTRA += -awith-breaking-changes
      +endif
      +
       ASCIIDOC_DEPS += docinfo.html
     @@ Documentation/gitrepository-layout.adoc: config.worktree::
       	working directory in multiple working directory setup (see
       	linkgit:git-worktree[1]).
       
     -+ifdef::without-breaking-changes[]
     ++ifndef::with-breaking-changes[]
       branches::
       	A deprecated way to store shorthands to be used
       	to specify a URL to 'git fetch', 'git pull' and 'git push'.
     @@ Documentation/gitrepository-layout.adoc: branches::
       	"$GIT_COMMON_DIR/branches" will be used instead.
       +
       Git will stop reading remotes from this directory in Git 3.0.
     -+endif::without-breaking-changes[]
     ++endif::with-breaking-changes[]
       
       hooks::
       	Hooks are customization scripts used by various Git
     @@ Documentation/gitrepository-layout.adoc: info/sparse-checkout::
       	This file stores sparse checkout patterns.
       	See also: linkgit:git-read-tree[1].
       
     -+ifdef::without-breaking-changes[]
     ++ifndef::with-breaking-changes[]
       remotes::
       	Stores shorthands for URL and default refnames for use
       	when interacting with remote repositories via 'git fetch',
     @@ Documentation/gitrepository-layout.adoc: remotes::
       	"$GIT_COMMON_DIR/remotes" will be used instead.
       +
       Git will stop reading remotes from this directory in Git 3.0.
     -+endif::without-breaking-changes[]
     ++endif::with-breaking-changes[]
       
       logs::
       	Records of changes made to refs are stored in this directory.
     @@ Documentation/meson.build: elif docs_backend == 'asciidoctor'
         ]
       endif
       
     -+if not get_option('breaking_changes')
     -+   asciidoc_common_options += ['--attribute', 'without-breaking-changes']
     ++if get_option('breaking_changes')
     ++   asciidoc_common_options += ['--attribute', 'with-breaking-changes']
      +endif
      +
     - git = find_program('git', required: false)
     - xmlto = find_program('xmlto')
     + xmlto = find_program('xmlto', dirs: program_path)
       
     + cmd_lists = [

 Documentation/Makefile                  | 4 ++++
 Documentation/gitrepository-layout.adoc | 4 ++++
 Documentation/meson.build               | 4 ++++
 3 files changed, 12 insertions(+)