Merge branch 'jc/you-still-use-whatchanged'

"git whatchanged" that is longer to type than "git log --raw"
which is its modern rough equivalent has outlived its usefulness
more than 10 years ago.  Plan to deprecate and remove it.

* jc/you-still-use-whatchanged:
  whatschanged: list it in BreakingChanges document
  whatchanged: remove when built with WITH_BREAKING_CHANGES
  whatchanged: require --i-still-use-this
  tests: prepare for a world without whatchanged
  doc: prepare for a world without whatchanged
  you-still-use-that??: help deprecating commands for removal

Documentation/BreakingChanges.adoc

@@ -183,6 +183,14 @@ These features will be removed.
   timeframe, in preference to its synonym "--annotate-stdin".  Git 3.0
   removes the support for "--stdin" altogether.
 
+* The git-whatchanged(1) command has outlived its usefulness more than
+  10 years ago, and takes more keystrokes to type than its rough
+  equivalent `git log --raw`.  We have nominated the command for
+  removal, have changed the command to refuse to work unless the
+  `--i-still-use-this` option is given, and asked the users to report
+  when they do so.  So far there hasn't been a single complaint.
++
+The command will be removed.
 
 == Superseded features that will not be deprecated
 

Documentation/Makefile

@@ -510,7 +510,12 @@ lint-docs-meson:
 	awk "/^manpages = {$$/ {flag=1 ; next } /^}$$/ { flag=0 } flag { gsub(/^  \047/, \"\"); gsub(/\047 : [157],\$$/, \"\"); print }" meson.build | \
 		grep -v -e '#' -e '^$$' | \
 		sort >tmp-meson-diff/meson.adoc && \
-	ls git*.adoc scalar.adoc | grep -v -e git-bisect-lk2009.adoc -e git-pack-redundant.adoc -e git-tools.adoc >tmp-meson-diff/actual.adoc && \
+	ls git*.adoc scalar.adoc | \
+		grep -v -e git-bisect-lk2009.adoc \
+			-e git-pack-redundant.adoc \
+			-e git-tools.adoc \
+			-e git-whatchanged.adoc \
+			>tmp-meson-diff/actual.adoc && \
 	if ! cmp tmp-meson-diff/meson.adoc tmp-meson-diff/actual.adoc; then \
 		echo "Meson man pages differ from actual man pages:"; \
 		diff -u tmp-meson-diff/meson.adoc tmp-meson-diff/actual.adoc; \

Documentation/MyFirstObjectWalk.adoc

@@ -83,13 +83,13 @@ int cmd_walken(int argc, const char **argv, const char *prefix)
 }
 ----
 
-Also add the relevant line in `builtin.h` near `cmd_whatchanged()`:
+Also add the relevant line in `builtin.h` near `cmd_version()`:
 
 ----
 int cmd_walken(int argc, const char **argv, const char *prefix, struct repository *repo);
 ----
 
-Include the command in `git.c` in `commands[]` near the entry for `whatchanged`,
+Include the command in `git.c` in `commands[]` near the entry for `version`,
 maintaining alphabetical ordering:
 
 ----

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

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::

Documentation/git-whatchanged.adoc

@@ -8,8 +8,14 @@ git-whatchanged - Show logs with differences each commit introduces
 
 SYNOPSIS
 --------
-[verse]
-'git whatchanged' <option>...
+[synopsis]
+git whatchanged <option>...
+
+WARNING
+-------
+`git whatchanged` has been deprecated and is scheduled for removal in
+a future version of Git, as it is merely `git log` with different
+default; `whatchanged` is not even shorter to type than `log --raw`.
 
 DESCRIPTION
 -----------

Documentation/meson.build

@@ -158,7 +158,6 @@ manpages = {
   'git-verify-tag.adoc' : 1,
   'git-version.adoc' : 1,
   'git-web--browse.adoc' : 1,
-  'git-whatchanged.adoc' : 1,
   'git-worktree.adoc' : 1,
   'git-write-tree.adoc' : 1,
   'git.adoc' : 1,
@@ -207,6 +206,7 @@ manpages = {
 
 manpages_breaking_changes = {
   'git-pack-redundant.adoc' : 1,
+  'git-whatchanged.adoc' : 1,
 }
 
 if not get_option('breaking_changes')

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.
 +

Documentation/rev-list-options.adoc

@@ -1100,8 +1100,13 @@ 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[]

Documentation/technical/sparse-checkout.adoc

@@ -440,7 +440,7 @@ 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

Documentation/user-manual.adoc

@@ -4240,7 +4240,7 @@ command `git`.  The source side of a builtin is
 - an entry in `BUILTIN_OBJECTS` in the `Makefile`.
 
 Sometimes, more than one builtin is contained in one source file.  For
-example, `cmd_whatchanged()` and `cmd_log()` both reside in `builtin/log.c`,
+example, `cmd_show()` and `cmd_log()` both reside in `builtin/log.c`,
 since they share quite a bit of code.  In that case, the commands which are
 _not_ named like the `.c` file in which they live have to be listed in
 `BUILT_INS` in the `Makefile`.

builtin/log.c

@@ -113,6 +113,15 @@ struct log_config {
 	int fmt_patch_name_max;
 	char *fmt_pretty;
 	char *default_date_mode;
+
+#ifndef WITH_BREAKING_CHANGES
+	/*
+	 * Note: git_log_config() does not touch this member and that
+	 * is very deliberate.  This member is only to be used to
+	 * resurrect whatchanged that is deprecated.
+	 */
+	int i_still_use_this;
+#endif
 };
 
 static void log_config_init(struct log_config *cfg)
@@ -267,6 +276,10 @@ static void cmd_log_init_finish(int argc, const char **argv, const char *prefix,
 		OPT__QUIET(&quiet, N_("suppress diff output")),
 		OPT_BOOL(0, "source", &source, N_("show source")),
 		OPT_BOOL(0, "use-mailmap", &mailmap, N_("use mail map file")),
+#ifndef WITH_BREAKING_CHANGES
+		OPT_HIDDEN_BOOL(0, "i-still-use-this", &cfg->i_still_use_this,
+				"<use this deprecated command>"),
+#endif
 		OPT_ALIAS(0, "mailmap", "use-mailmap"),
 		OPT_CALLBACK_F(0, "clear-decorations", NULL, NULL,
 			       N_("clear all previously-defined decoration filters"),
@@ -633,6 +646,7 @@ static int git_log_config(const char *var, const char *value,
 	return git_diff_ui_config(var, value, ctx, cb);
 }
 
+#ifndef WITH_BREAKING_CHANGES
 int cmd_whatchanged(int argc,
 		    const char **argv,
 		    const char *prefix,
@@ -656,6 +670,10 @@ int cmd_whatchanged(int argc,
 	opt.def = "HEAD";
 	opt.revarg_opt = REVARG_COMMITTISH;
 	cmd_log_init(argc, argv, prefix, &rev, &opt, &cfg);
+
+	if (!cfg.i_still_use_this)
+		you_still_use_that("git whatchanged");
+
 	if (!rev.diffopt.output_format)
 		rev.diffopt.output_format = DIFF_FORMAT_RAW;
 
@@ -665,6 +683,7 @@ int cmd_whatchanged(int argc,
 	log_config_release(&cfg);
 	return ret;
 }
+#endif
 
 static void show_tagger(const char *buf, struct rev_info *rev)
 {

builtin/pack-redundant.c

@@ -625,14 +625,8 @@ int cmd_pack_redundant(int argc, const char **argv, const char *prefix UNUSED, s
 			break;
 	}
 
-	if (!i_still_use_this) {
-		fputs(_("'git pack-redundant' is nominated for removal.\n"
-			"If you still use this command, please add an extra\n"
-			"option, '--i-still-use-this', on the command line\n"
-			"and let us know you still use it by sending an e-mail\n"
-			"to <git@vger.kernel.org>.  Thanks.\n"), stderr);
-		die(_("refusing to run without --i-still-use-this"));
-	}
+	if (!i_still_use_this)
+		you_still_use_that("git pack-redundant");
 
 	if (load_all_packs)
 		load_all();

git-compat-util.h

@@ -460,6 +460,8 @@ void warning_errno(const char *err, ...) __attribute__((format (printf, 1, 2)));
 
 void show_usage_if_asked(int ac, const char **av, const char *err);
 
+NORETURN void you_still_use_that(const char *command_name);
+
 #ifndef NO_OPENSSL
 #ifdef APPLE_COMMON_CRYPTO
 #include "compat/apple-common-crypto.h"

git.c

@@ -646,7 +646,9 @@ static struct cmd_struct commands[] = {
 	{ "verify-pack", cmd_verify_pack },
 	{ "verify-tag", cmd_verify_tag, RUN_SETUP },
 	{ "version", cmd_version },
+#ifndef WITH_BREAKING_CHANGES
 	{ "whatchanged", cmd_whatchanged, RUN_SETUP },
+#endif
 	{ "worktree", cmd_worktree, RUN_SETUP },
 	{ "write-tree", cmd_write_tree, RUN_SETUP },
 };

t/t4013-diff-various.sh

@@ -206,14 +206,30 @@ do
 	expect="$TEST_DIRECTORY/t4013/diff.$test"
 	actual="$pfx-diff.$test"
 
-	test_expect_success "git $cmd # magic is ${magic:-(not used)}" '
+	case "$cmd" in
+	whatchanged | whatchanged" "*)
+		prereq=!WITH_BREAKING_CHANGES
+		;;
+	*)
+		prereq=;;
+	esac
+
+	test_expect_success $prereq "git $cmd # magic is ${magic:-(not used)}" '
 		{
 			echo "$ git $cmd"
+
+			case "$cmd" in
+			whatchanged | whatchanged" "*)
+				run="whatchanged --i-still-use-this"
+				run="$run ${cmd#whatchanged}" ;;
+			*)
+				run=$cmd ;;
+			esac &&
 			case "$magic" in
 			"")
-				GIT_PRINT_SHA1_ELLIPSIS=yes git $cmd ;;
+				GIT_PRINT_SHA1_ELLIPSIS=yes git $run ;;
 			noellipses)
-				git $cmd ;;
+				git $run ;;
 			esac |
 			sed -e "s/^\\(-*\\)$V\\(-*\\)\$/\\1g-i-t--v-e-r-s-i-o-n\2/" \
 			    -e "s/^\\(.*mixed; boundary=\"-*\\)$V\\(-*\\)\"\$/\\1g-i-t--v-e-r-s-i-o-n\2\"/"
@@ -460,6 +476,11 @@ diff-tree --stat --compact-summary initial mode
 diff-tree -R --stat --compact-summary initial mode
 EOF
 
+test_expect_success !WITH_BREAKING_CHANGES 'whatchanged needs --i-still-use-this' '
+	test_must_fail git whatchanged >message 2>&1 &&
+	test_grep "nominated for removal" message
+'
+
 test_expect_success 'log -m matches pure log' '
 	git log master >result &&
 	process_diffs result >expected &&

t/t4202-log.sh

@@ -486,10 +486,16 @@ test_expect_success !FAIL_PREREQS 'log with various grep.patternType configurati
 	)
 '
 
-for cmd in show whatchanged reflog format-patch
+cmds="show reflog format-patch"
+if test_have_prereq !WITH_BREAKING_CHANGES
+then
+	cmds="$cmds whatchanged"
+fi
+for cmd in $cmds
 do
 	case "$cmd" in
 	format-patch) myarg="HEAD~.." ;;
+	whatchanged) myarg=--i-still-use-this ;;
 	*) myarg= ;;
 	esac
 
@@ -1201,20 +1207,27 @@ test_expect_success 'reflog is expected format' '
 	test_cmp expect actual
 '
 
-test_expect_success 'whatchanged is expected format' '
+test_expect_success !WITH_BREAKING_CHANGES 'whatchanged is expected format' '
+	whatchanged="whatchanged --i-still-use-this" &&
 	git log --no-merges --raw >expect &&
-	git whatchanged >actual &&
+	git $whatchanged >actual &&
 	test_cmp expect actual
 '
 
 test_expect_success 'log.abbrevCommit configuration' '
+	whatchanged="whatchanged --i-still-use-this" &&
+
 	git log --abbrev-commit >expect.log.abbrev &&
 	git log --no-abbrev-commit >expect.log.full &&
 	git log --pretty=raw >expect.log.raw &&
 	git reflog --abbrev-commit >expect.reflog.abbrev &&
 	git reflog --no-abbrev-commit >expect.reflog.full &&
-	git whatchanged --abbrev-commit >expect.whatchanged.abbrev &&
-	git whatchanged --no-abbrev-commit >expect.whatchanged.full &&
+
+	if test_have_prereq !WITH_BREAKING_CHANGES
+	then
+		git $whatchanged --abbrev-commit >expect.whatchanged.abbrev &&
+		git $whatchanged --no-abbrev-commit >expect.whatchanged.full
+	fi &&
 
 	test_config log.abbrevCommit true &&
 
@@ -1231,10 +1244,13 @@ test_expect_success 'log.abbrevCommit configuration' '
 	git reflog --no-abbrev-commit >actual &&
 	test_cmp expect.reflog.full actual &&
 
-	git whatchanged >actual &&
-	test_cmp expect.whatchanged.abbrev actual &&
-	git whatchanged --no-abbrev-commit >actual &&
-	test_cmp expect.whatchanged.full actual
+	if test_have_prereq !WITH_BREAKING_CHANGES
+	then
+		git $whatchanged >actual &&
+		test_cmp expect.whatchanged.abbrev actual &&
+		git $whatchanged --no-abbrev-commit >actual &&
+		test_cmp expect.whatchanged.full actual
+	fi
 '
 
 test_expect_success '--abbrev-commit with core.abbrev=false' '

t/t5323-pack-redundant.sh

@@ -45,6 +45,11 @@ fi
 main_repo=main.git
 shared_repo=shared.git
 
+test_expect_success 'pack-redundant needs --i-still-use-this' '
+	test_must_fail git pack-redundant >message 2>&1 &&
+	test_grep "nominated for removal" message
+'
+
 git_pack_redundant='git pack-redundant --i-still-use-this'
 
 # Create commits in <repo> and assign each commit's oid to shell variables

t/t9300-fast-import.sh

@@ -120,7 +120,7 @@ test_expect_success 'A: create pack from stdin' '
 
 	INPUT_END
 	git fast-import --export-marks=marks.out <input &&
-	git whatchanged main
+	git log --raw main
 '
 
 test_expect_success 'A: verify pack' '
@@ -279,7 +279,7 @@ test_expect_success 'A: verify marks import does not crash' '
 	INPUT_END
 
 	git fast-import --import-marks=marks.out <input &&
-	git whatchanged verify--import-marks
+	git log --raw verify--import-marks
 '
 
 test_expect_success 'A: verify pack' '
@@ -652,7 +652,7 @@ test_expect_success 'C: incremental import create pack from stdin' '
 	INPUT_END
 
 	git fast-import <input &&
-	git whatchanged branch
+	git log --raw branch
 '
 
 test_expect_success 'C: verify pack' '
@@ -715,7 +715,7 @@ test_expect_success 'D: inline data in commit' '
 	INPUT_END
 
 	git fast-import <input &&
-	git whatchanged branch
+	git log --raw branch
 '
 
 test_expect_success 'D: verify pack' '
@@ -882,7 +882,7 @@ test_expect_success 'H: deletall, add 1' '
 
 	INPUT_END
 	git fast-import <input &&
-	git whatchanged H
+	git log --raw H
 '
 
 test_expect_success 'H: verify pack' '
@@ -2066,7 +2066,7 @@ test_expect_success 'Q: commit notes' '
 	INPUT_END
 
 	git fast-import <input &&
-	git whatchanged notes-test
+	git log --raw notes-test
 '
 
 test_expect_success 'Q: verify pack' '

t/t9301-fast-import-notes.sh

@@ -76,7 +76,7 @@ INPUT_END
 test_expect_success 'set up main branch' '
 
 	git fast-import <input &&
-	git whatchanged main
+	git log --raw main
 '
 
 commit4=$(git rev-parse refs/heads/main)

usage.c

@@ -372,3 +372,15 @@ void bug_fl(const char *file, int line, const char *fmt, ...)
 	trace2_cmd_error_va(fmt, ap);
 	va_end(ap);
 }
+
+NORETURN void you_still_use_that(const char *command_name)
+{
+	fprintf(stderr,
+		_("'%s' is nominated for removal.\n"
+		  "If you still use this command, please add an extra\n"
+		  "option, '--i-still-use-this', on the command line\n"
+		  "and let us know you still use it by sending an e-mail\n"
+		  "to <git@vger.kernel.org>.  Thanks.\n"),
+		command_name);
+	die(_("refusing to run without --i-still-use-this"));
+}