Merge branch 'tr/rev-list-count'

* tr/rev-list-count:
  bash completion: Support "divergence from upstream" messages in __git_ps1
  rev-list: introduce --count option

Conflicts:
	contrib/completion/git-completion.bash

Documentation/rev-list-options.txt

@@ -98,6 +98,15 @@ you would get an output like this:
 This implies the '--topo-order' option by default, but the
 '--date-order' option may also be specified.
 
+ifdef::git-rev-list[]
+--count::
+	Print a number stating how many commits would have been
+	listed, and suppress all other output.  When used together
+	with '--left-right', instead print the counts for left and
+	right commits, separated by a tab.
+endif::git-rev-list[]
+
+
 ifndef::git-rev-list[]
 Diff Formatting
 ~~~~~~~~~~~~~~~

builtin/rev-list.c

@@ -50,6 +50,15 @@ static void show_commit(struct commit *commit, void *data)
 
 	graph_show_commit(revs->graph);
 
+	if (revs->count) {
+		if (commit->object.flags & SYMMETRIC_LEFT)
+			revs->count_left++;
+		else
+			revs->count_right++;
+		finish_commit(commit, data);
+		return;
+	}
+
 	if (info->show_timestamp)
 		printf("%lu ", commit->date);
 	if (info->header_prefix)
@@ -400,5 +409,12 @@ int cmd_rev_list(int argc, const char **argv, const char *prefix)
 			     quiet ? finish_object : show_object,
 			     &info);
 
+	if (revs.count) {
+		if (revs.left_right)
+			printf("%d\t%d\n", revs.count_left, revs.count_right);
+		else
+			printf("%d\n", revs.count_left + revs.count_right);
+	}
+
 	return 0;
 }

contrib/completion/git-completion.bash

@@ -42,6 +42,24 @@
 #       set GIT_PS1_SHOWUNTRACKEDFILES to a nonempty value. If there're
 #       untracked files, then a '%' will be shown next to the branch name.
 #
+#       If you would like to see the difference between HEAD and its
+#       upstream, set GIT_PS1_SHOWUPSTREAM="auto".  A "<" indicates
+#       you are behind, ">" indicates you are ahead, and "<>"
+#       indicates you have diverged.  You can further control
+#       behaviour by setting GIT_PS1_SHOWUPSTREAM to a space-separated
+#       list of values:
+#           verbose       show number of commits ahead/behind (+/-) upstream
+#           legacy        don't use the '--count' option available in recent
+#                         versions of git-rev-list
+#           git           always compare HEAD to @{upstream}
+#           svn           always compare HEAD to your SVN upstream
+#       By default, __git_ps1 will compare HEAD to your SVN upstream
+#       if it can find one, or @{upstream} otherwise.  Once you have
+#       set GIT_PS1_SHOWUPSTREAM, you can override it on a
+#       per-repository basis by setting the bash.showUpstream config
+#       variable.
+#
+#
 # To submit patches:
 #
 #    *) Read Documentation/SubmittingPatches
@@ -78,6 +96,125 @@ __gitdir ()
 	fi
 }
 
+# stores the divergence from upstream in $p
+# used by GIT_PS1_SHOWUPSTREAM
+__git_ps1_show_upstream ()
+{
+	local key value
+	local svn_remote=() svn_url_pattern count n
+	local upstream=git legacy="" verbose=""
+
+	# get some config options from git-config
+	while read key value; do
+		case "$key" in
+		bash.showupstream)
+			GIT_PS1_SHOWUPSTREAM="$value"
+			if [[ -z "${GIT_PS1_SHOWUPSTREAM}" ]]; then
+				p=""
+				return
+			fi
+			;;
+		svn-remote.*.url)
+			svn_remote[ $((${#svn_remote[@]} + 1)) ]="$value"
+			svn_url_pattern+="\\|$value"
+			upstream=svn+git # default upstream is SVN if available, else git
+			;;
+		esac
+	done < <(git config -z --get-regexp '^(svn-remote\..*\.url|bash\.showupstream)$' 2>/dev/null | tr '\0\n' '\n ')
+
+	# parse configuration values
+	for option in ${GIT_PS1_SHOWUPSTREAM}; do
+		case "$option" in
+		git|svn) upstream="$option" ;;
+		verbose) verbose=1 ;;
+		legacy)  legacy=1  ;;
+		esac
+	done
+
+	# Find our upstream
+	case "$upstream" in
+	git)    upstream="@{upstream}" ;;
+	svn*)
+		# get the upstream from the "git-svn-id: ..." in a commit message
+		# (git-svn uses essentially the same procedure internally)
+		local svn_upstream=($(git log --first-parent -1 \
+					--grep="^git-svn-id: \(${svn_url_pattern:2}\)" 2>/dev/null))
+		if [[ 0 -ne ${#svn_upstream[@]} ]]; then
+			svn_upstream=${svn_upstream[ ${#svn_upstream[@]} - 2 ]}
+			svn_upstream=${svn_upstream%@*}
+			for ((n=1; "$n" <= "${#svn_remote[@]}"; ++n)); do
+				svn_upstream=${svn_upstream#${svn_remote[$n]}}
+			done
+
+			if [[ -z "$svn_upstream" ]]; then
+				# default branch name for checkouts with no layout:
+				upstream=${GIT_SVN_ID:-git-svn}
+			else
+				upstream=${svn_upstream#/}
+			fi
+		elif [[ "svn+git" = "$upstream" ]]; then
+			upstream="@{upstream}"
+		fi
+		;;
+	esac
+
+	# Find how many commits we are ahead/behind our upstream
+	if [[ -z "$legacy" ]]; then
+		count="$(git rev-list --count --left-right \
+				"$upstream"...HEAD 2>/dev/null)"
+	else
+		# produce equivalent output to --count for older versions of git
+		local commits
+		if commits="$(git rev-list --left-right "$upstream"...HEAD 2>/dev/null)"
+		then
+			local commit behind=0 ahead=0
+			for commit in $commits
+			do
+				case "$commit" in
+				"<"*) let ++behind
+					;;
+				*)    let ++ahead
+					;;
+				esac
+			done
+			count="$behind	$ahead"
+		else
+			count=""
+		fi
+	fi
+
+	# calculate the result
+	if [[ -z "$verbose" ]]; then
+		case "$count" in
+		"") # no upstream
+			p="" ;;
+		"0	0") # equal to upstream
+			p="=" ;;
+		"0	"*) # ahead of upstream
+			p=">" ;;
+		*"	0") # behind upstream
+			p="<" ;;
+		*)	    # diverged from upstream
+			p="<>" ;;
+		esac
+	else
+		case "$count" in
+		"") # no upstream
+			p="" ;;
+		"0	0") # equal to upstream
+			p=" u=" ;;
+		"0	"*) # ahead of upstream
+			p=" u+${count#0	}" ;;
+		*"	0") # behind upstream
+			p=" u-${count%	0}" ;;
+		*)	    # diverged from upstream
+			p=" u+${count#*	}-${count%	*}" ;;
+		esac
+	fi
+
+}
+
+
 # __git_ps1 accepts 0 or 1 arguments (i.e., format string)
 # returns text to add to bash PS1 prompt (includes branch name)
 __git_ps1 ()
@@ -132,6 +269,7 @@ __git_ps1 ()
 		local s=""
 		local u=""
 		local c=""
+		local p=""
 
 		if [ "true" = "$(git rev-parse --is-inside-git-dir 2>/dev/null)" ]; then
 			if [ "true" = "$(git rev-parse --is-bare-repository 2>/dev/null)" ]; then
@@ -159,10 +297,14 @@ __git_ps1 ()
 			      u="%"
 			   fi
 			fi
+
+			if [ -n "${GIT_PS1_SHOWUPSTREAM-}" ]; then
+				__git_ps1_show_upstream
+			fi
 		fi
 
 		local f="$w$i$s$u"
-		printf "${1:- (%s)}" "$c${b##refs/heads/}${f:+ $f}$r"
+		printf "${1:- (%s)}" "$c${b##refs/heads/}${f:+ $f}$r$p"
 	fi
 }
 

revision.c

@@ -1253,6 +1253,8 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
 		revs->boundary = 1;
 	} else if (!strcmp(arg, "--left-right")) {
 		revs->left_right = 1;
+	} else if (!strcmp(arg, "--count")) {
+		revs->count = 1;
 	} else if (!strcmp(arg, "--cherry-pick")) {
 		revs->cherry_pick = 1;
 		revs->limited = 1;

revision.h

@@ -57,6 +57,7 @@ struct rev_info {
 			limited:1,
 			unpacked:1,
 			boundary:2,
+			count:1,
 			left_right:1,
 			rewrite_parents:1,
 			print_parents:1,
@@ -132,6 +133,10 @@ struct rev_info {
 
 	/* notes-specific options: which refs to show */
 	struct display_notes_opt notes_opt;
+
+	/* commit counts */
+	int count_left;
+	int count_right;
 };
 
 #define REV_TREE_SAME		0

t/t6007-rev-list-cherry-pick-file.sh

@@ -32,6 +32,23 @@ test_expect_success setup '
 	git tag B
 '
 
+cat >expect <<EOF
+<tags/B
+>tags/C
+EOF
+
+test_expect_success '--left-right' '
+	git rev-list --left-right B...C > actual &&
+	git name-rev --stdin --name-only --refs="*tags/*" \
+		< actual > actual.named &&
+	test_cmp actual.named expect
+'
+
+test_expect_success '--count' '
+	git rev-list --count B...C > actual &&
+	test "$(cat actual)" = 2
+'
+
 test_expect_success '--cherry-pick foo comes up empty' '
 	test -z "$(git rev-list --left-right --cherry-pick B...C -- foo)"
 '
@@ -54,4 +71,16 @@ test_expect_success '--cherry-pick with independent, but identical branches' '
 		HEAD...master -- foo)"
 '
 
+cat >expect <<EOF
+1	2
+EOF
+
+# Insert an extra commit to break the symmetry
+test_expect_success '--count --left-right' '
+	git checkout branch &&
+	test_commit D &&
+	git rev-list --count --left-right B...D > actual &&
+	test_cmp expect actual
+'
+
 test_done