whatchanged: remove when built with WITH_BREAKING_CHANGES

As we made "git whatchanged" require "--i-still-use-this" and asked
the users to report if they still want to use it, the logical next
step is to allow us build Git without "whatchanged" to prepare for
its eventual removal.

If we were to follow the pattern established in 8ccc75c2 (remote:
announce removal of "branches/" and "remotes/", 2025-01-22), we can
do this together with the documentation update to officially list
that the command will be removed in the BreakingChanges document,
but let's just keep the changes separate just in case we want to
proceed a bit slower.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

5 files changed, 28 insertions, 5 deletions

diff --git a/Documentation/config/format.adoc b/Documentation/config/format.adoc
index 7410e930e5..ab0710e86a 100644
--- a/Documentation/config/format.adoc
+++ b/Documentation/config/format.adoc
@@ -68,9 +68,15 @@ format.encodeEmailHeaders::
 	Defaults to true.
 
 format.pretty::
+ifndef::with-breaking-changes[]
 	The default pretty format for log/show/whatchanged command.
 	See linkgit:git-log[1], linkgit:git-show[1],
 	linkgit:git-whatchanged[1].
+endif::with-breaking-changes[]
+ifdef::with-breaking-changes[]
+	The default pretty format for log/show command.
+	See linkgit:git-log[1], linkgit:git-show[1].
+endif::with-breaking-changes[]
 
 format.thread::
 	The default threading style for 'git format-patch'.  Can be
diff --git a/Documentation/config/log.adoc b/Documentation/config/log.adoc
index 9003a82191..a9b160e7de 100644
--- a/Documentation/config/log.adoc
+++ b/Documentation/config/log.adoc
@@ -1,6 +1,13 @@
 log.abbrevCommit::
-	If true, makes linkgit:git-log[1], linkgit:git-show[1], and
-	linkgit:git-whatchanged[1] assume `--abbrev-commit`. You may
+	If true, makes
+ifndef::with-breaking-changes[]
+	linkgit:git-log[1], linkgit:git-show[1], and
+	linkgit:git-whatchanged[1]
+endif::with-breaking-changes[]
+ifdef::with-breaking-changes[]
+	linkgit:git-log[1] and linkgit:git-show[1]
+endif::with-breaking-changes[]
+	assume `--abbrev-commit`. You may
 	override this option with `--no-abbrev-commit`.
 
 log.date::
diff --git a/Documentation/pretty-options.adoc b/Documentation/pretty-options.adoc
index 23888cd612..b36e96abe2 100644
--- a/Documentation/pretty-options.adoc
+++ b/Documentation/pretty-options.adoc
@@ -62,7 +62,12 @@ ifndef::git-rev-list[]
 --notes[=<ref>]::
 	Show the notes (see linkgit:git-notes[1]) that annotate the
 	commit, when showing the commit log message.  This is the default
+ifndef::with-breaking-changes[]
 	for `git log`, `git show` and `git whatchanged` commands when
+endif::with-breaking-changes[]
+ifdef::with-breaking-changes[]
+	for `git log` and `git show` commands when
+endif::with-breaking-changes[]
 	there is no `--pretty`, `--format`, or `--oneline` option given
 	on the command line.
 +
diff --git a/Documentation/rev-list-options.adoc b/Documentation/rev-list-options.adoc
index 785c0786e0..ee5c5c9489 100644
--- a/Documentation/rev-list-options.adoc
+++ b/Documentation/rev-list-options.adoc
@@ -1074,8 +1074,13 @@ Commit Formatting
 
 ifdef::git-rev-list[]
 Using these options, linkgit:git-rev-list[1] will act similar to the
-more specialized family of commit log tools: linkgit:git-log[1],
-linkgit:git-show[1], and linkgit:git-whatchanged[1]
+more specialized family of commit log tools:
+ifndef::with-breaking-changes[]
+linkgit:git-log[1], linkgit:git-show[1], and linkgit:git-whatchanged[1].
+endif::with-breaking-changes[]
+ifdef::with-breaking-changes[]
+linkgit:git-log[1] and linkgit:git-show[1].
+endif::with-breaking-changes[]
 endif::git-rev-list[]
 
 include::pretty-options.adoc[]
diff --git a/Documentation/technical/sparse-checkout.adoc b/Documentation/technical/sparse-checkout.adoc
index d968659354..67134bb768 100644
--- a/Documentation/technical/sparse-checkout.adoc
+++ b/Documentation/technical/sparse-checkout.adoc
@@ -442,7 +442,7 @@ understanding these differences can be beneficial.
       * blame (only matters when one or more -C flags are passed)
 	* and annotate
       * log
-      * whatchanged
+      * whatchanged (may not exist anymore)
       * ls-files
       * diff-index
       * diff-tree