tools: support v run cmd/tools/oldv.v --show_VC_commit weekly.2024.03

cmd/tools/modules/vgit/vgit.v

@@ -137,12 +137,14 @@ pub mut:
 	vexepath       string // the full absolute path to the prepared v/v.exe
 	vvlocation     string // v.v or compiler/ or cmd/v, depending on v version
 	make_fresh_tcc bool   // whether to do 'make fresh_tcc' before compiling an old V.
+	show_vccommit  bool   // show the V and VC commits, corresponding to the V commit-ish, that can be used to build V
 }
 
 pub fn (mut vgit_context VGitContext) compile_oldv_if_needed() {
 	vgit_context.vexename = if os.user_os() == 'windows' { 'v.exe' } else { 'v' }
 	vgit_context.vexepath = os.real_path(os.join_path_single(vgit_context.path_v, vgit_context.vexename))
-	if os.is_dir(vgit_context.path_v) && os.is_executable(vgit_context.vexepath) {
+	if os.is_dir(vgit_context.path_v) && os.is_executable(vgit_context.vexepath)
+		&& !vgit_context.show_vccommit {
 		// already compiled, no need to compile that specific v executable again
 		vgit_context.commit_v__hash = get_current_folder_commit_hash()
 		return
@@ -152,7 +154,8 @@ pub fn (mut vgit_context VGitContext) compile_oldv_if_needed() {
 	clone_or_pull(vgit_context.vc_repo_url, vgit_context.path_vc)
 	scripting.chdir(vgit_context.path_v)
 	scripting.run('git checkout --quiet ${vgit_context.commit_v}')
-	if os.is_dir(vgit_context.path_v) && os.exists(vgit_context.vexepath) {
+	if os.is_dir(vgit_context.path_v) && os.exists(vgit_context.vexepath)
+		&& !vgit_context.show_vccommit {
 		// already compiled, so no need to compile v again
 		vgit_context.commit_v__hash = get_current_folder_commit_hash()
 		return
@@ -162,6 +165,13 @@ pub fn (mut vgit_context VGitContext) compile_oldv_if_needed() {
 	vgit_context.commit_v__hash = v_commithash
 	vgit_context.commit_v__ts = v_timestamp
 	vgit_context.commit_vc_hash = vccommit_before
+
+	if vgit_context.show_vccommit {
+		println('VHASH=${vgit_context.commit_v__hash}')
+		println('VCHASH=${vgit_context.commit_vc_hash}')
+		exit(0)
+	}
+
 	if os.exists('cmd/v') {
 		vgit_context.vvlocation = 'cmd/v'
 	} else {

cmd/tools/oldv.v

@@ -39,6 +39,7 @@ mut:
 	use_cache     bool   // use local cached copies for --vrepo and --vcrepo in
 	fresh_tcc     bool   // do use `make fresh_tcc`
 	is_bisect     bool   // bisect mode; usage: `cmd/tools/oldv -b -c './v run bug.v'`
+	show_vccommit bool   // show the V and VC commits, corresponding to the V commit-ish, that can be used to build V
 }
 
 fn (mut c Context) compile_oldv_if_needed() {
@@ -51,6 +52,7 @@ fn (mut c Context) compile_oldv_if_needed() {
 		path_v: c.path_v
 		path_vc: c.path_vc
 		make_fresh_tcc: c.fresh_tcc
+		show_vccommit: c.show_vccommit
 	}
 	c.vgcontext.compile_oldv_if_needed()
 	c.commit_v_hash = c.vgcontext.commit_v__hash
@@ -133,6 +135,7 @@ fn main() {
 	context.cleanup = fp.bool('clean', 0, false, 'Clean before running (slower).')
 	context.fresh_tcc = fp.bool('fresh_tcc', 0, true, 'Do `make fresh_tcc` when preparing a V compiler.')
 	context.cmd_to_run = fp.string('command', `c`, '', 'Command to run in the old V repo.\n')
+	context.show_vccommit = fp.bool('show_VC_commit', 0, false, 'Show the VC commit, that can be used to compile the given V commit, and exit.\n')
 	commits := vgit.add_common_tool_options(mut context.vgo, mut fp)
 	if should_sync {
 		sync_cache()
@@ -152,7 +155,9 @@ fn main() {
 	} else {
 		context.commit_v = scripting.run('git rev-list -n1 HEAD')
 	}
-	scripting.cprintln('#################  context.commit_v: ${context.commit_v} #####################')
+	if !context.show_vccommit {
+		scripting.cprintln('#################  context.commit_v: ${context.commit_v} #####################')
+	}
 	context.path_v = vgit.normalized_workpath_for_commit(context.vgo.workdir, context.commit_v)
 	context.path_vc = vgit.normalized_workpath_for_commit(context.vgo.workdir, 'vc')
 	if !os.is_dir(context.vgo.workdir) {