v.utils: update githash to be able to get the githash of every passed project

cmd/tools/vup.v

@@ -35,8 +35,8 @@ fn main() {
 	os.chdir(app.vroot)!
 	println('Updating V...')
 	app.update_from_master()
-	v_hash := version.githash(false)
-	current_hash := version.githash(true)
+	v_hash := @VCURRENTHASH
+	current_hash := version.githash(vroot) or { v_hash }
 	// println(v_hash)
 	// println(current_hash)
 	if v_hash == current_hash && !app.skip_current {

vlib/v/checker/checker.v

@@ -149,7 +149,8 @@ pub fn new_checker(table &ast.Table, pref_ &pref.Preferences) &Checker {
 		pref: pref_
 		timers: util.new_timers(should_print: timers_should_print, label: 'checker')
 		match_exhaustive_cutoff_limit: pref_.checker_match_exhaustive_cutoff_limit
-		v_current_commit_hash: version.githash(pref_.building_v)
+		v_current_commit_hash: if pref_.building_v { version.githash(pref_.vroot) or {
+				@VCURRENTHASH} } else { @VCURRENTHASH }
 	}
 	checker.comptime = &comptime.ComptimeInfo{
 		resolver: checker

vlib/v/util/version/version.c.v

@@ -17,7 +17,7 @@ pub fn vhash() string {
 
 pub fn full_hash() string {
 	build_hash := vhash()
-	current_hash := githash(false)
+	current_hash := @VCURRENTHASH
 	if build_hash == current_hash {
 		return build_hash
 	}
@@ -29,52 +29,35 @@ pub fn full_v_version(is_verbose bool) string {
 	if is_verbose {
 		return 'V ${version.v_version} ${full_hash()}'
 	}
-	hash := githash(false)
-	return 'V ${version.v_version} ${hash}'
+	return 'V ${version.v_version} ${@VCURRENTHASH}'
 }
 
-// githash(x) returns the current git commit hash.
-// When x is false, it is very fast - it just returns a predefined C constant.
-// When x is true, it tries to get the current commit hash, by parsing the
-// relevant files in the .git/ folder, or if that is not possible
-// for example when using a V from a V binary release, that does not have .git/
-// defaults to getting the predefined C constant again.
-// Note: githash(true) must be called only when v detects that it builds itself.
-// For all other programs, githash(false) should be used.
-pub fn githash(should_get_from_filesystem bool) string {
-	for {
-		// The `for` construct here is used as a goto substitute.
-		// The code in this function will break out of the `for`
-		// if it detects an error and can not continue.
-		if should_get_from_filesystem {
-			vexe := os.getenv('VEXE')
-			vroot := os.dir(vexe)
-			// .git/HEAD
-			git_head_file := os.join_path(vroot, '.git', 'HEAD')
-			if !os.exists(git_head_file) {
-				break
-			}
-			// 'ref: refs/heads/master' ... the current branch name
-			head_content := os.read_file(git_head_file) or { break }
-			mut current_branch_hash := head_content
-			if head_content.starts_with('ref: ') {
-				gcbranch_rel_path := head_content.replace('ref: ', '').trim_space()
-				gcbranch_file := os.join_path(vroot, '.git', gcbranch_rel_path)
-				// .git/refs/heads/master
-				if !os.exists(gcbranch_file) {
-					break
-				}
-				// get the full commit hash contained in the ref heads file
-				branch_hash := os.read_file(gcbranch_file) or { break }
-				current_branch_hash = branch_hash
-			}
-			desired_hash_length := 7
-			if current_branch_hash.len > desired_hash_length {
-				return current_branch_hash[0..desired_hash_length]
-			}
+// githash tries to find the current git commit hash for the specified
+// project path by parsing the relevant files in its `.git/` folder.
+pub fn githash(path string) !string {
+	// .git/HEAD
+	git_head_file := os.join_path(path, '.git', 'HEAD')
+	if !os.exists(git_head_file) {
+		return error('failed to find `${git_head_file}`')
+	}
+	// 'ref: refs/heads/master' ... the current branch name
+	head_content := os.read_file(git_head_file) or {
+		return error('failed to read `${git_head_file}`')
+	}
+	current_branch_hash := if head_content.starts_with('ref: ') {
+		rev_rel_path := head_content.replace('ref: ', '').trim_space()
+		rev_file := os.join_path(path, '.git', rev_rel_path)
+		// .git/refs/heads/master
+		if !os.exists(rev_file) {
+			return error('failed to find revision file `${rev_file}`')
 		}
-		break
+		// get the full commit hash contained in the ref heads file
+		os.read_file(rev_file) or { return error('failed to read revision file `${rev_file}`') }
+	} else {
+		head_content
+	}
+	desired_hash_length := 7
+	return current_branch_hash[0..desired_hash_length] or {
+		error('failed to limit hash `${current_branch_hash}` to ${desired_hash_length} characters')
 	}
-
-	return @VCURRENTHASH
 }

vlib/v/util/version/version_test.v

@@ -0,0 +1,38 @@
+import v.util.version
+import os
+
+fn test_githash() {
+	if !os.exists(os.join_path(@VMODROOT, '.git')) {
+		eprintln('> skipping test due to missing V .git directory')
+		return
+	}
+	sha := version.githash(@VMODROOT)!
+	assert sha == @VCURRENTHASH
+
+	git_proj_path := os.join_path(os.vtmp_dir(), 'test_githash')
+	defer {
+		os.rmdir_all(git_proj_path) or {}
+	}
+	os.execute_opt('git init ${git_proj_path}')!
+	os.chdir(git_proj_path)!
+	if sha_ := version.githash(git_proj_path) {
+		assert false, 'Should not have found an unknown revision'
+	} else {
+		assert err.msg().contains('failed to find revision file'), err.msg()
+	}
+	os.execute_opt('git config user.name') or {
+		os.execute_opt('git config user.email "ci@vlang.io"')!
+		os.execute_opt('git config user.name "V CI"')!
+	}
+	os.write_file('v.mod', '')!
+	os.execute_opt('git add .')!
+	os.execute_opt('git commit -m "test1"')!
+	test_rev := os.execute_opt('git rev-parse --short HEAD')!.output.trim_space()
+	assert test_rev == version.githash(git_proj_path)!
+	os.write_file('README.md', '')!
+	os.execute_opt('git add .')!
+	os.execute_opt('git commit -m "test2"')!
+	test_rev2 := os.execute_opt('git rev-parse --short HEAD')!.output.trim_space()
+	assert test_rev2 != test_rev
+	assert test_rev2 == version.githash(git_proj_path)!
+}