Use named return parameters

We allow them, but don't do anything with them yet.

go/extractor/cli/go-autobuilder/go-autobuilder.go

@@ -61,11 +61,19 @@ var goVersion = ""
 // Returns the current Go version as returned by 'go version', e.g. go1.14.4
 func getEnvGoVersion() string {
 	if goVersion == "" {
-		gover, err := exec.Command("go", "version").CombinedOutput()
+		// Since Go 1.21, running 'go version' in a directory with a 'go.mod' file will attempt to
+		// download the version of Go specified in there. That may either fail or result in us just
+		// being told what's already in 'go.mod'. Setting 'GOTOOLCHAIN' to 'local' will force it
+		// to use the local Go toolchain instead.
+		cmd := exec.Command("go", "version")
+		cmd.Env = append(os.Environ(), "GOTOOLCHAIN=local")
+		out, err := cmd.CombinedOutput()
+
 		if err != nil {
 			log.Fatalf("Unable to run the go command, is it installed?\nError: %s", err.Error())
 		}
-		goVersion = parseGoVersion(string(gover))
+
+		goVersion = parseGoVersion(string(out))
 	}
 	return goVersion
 }
@@ -367,23 +375,46 @@ func getDepMode(emitDiagnostics bool) (DependencyInstallerMode, string) {
 	return GoGetNoModules, "."
 }
 
+type GoVersionInfo struct {
+	// The version string, if any
+	Version string
+	// A value indicating whether a version string was found
+	Found bool
+}
+
 // Tries to open `go.mod` and read a go directive, returning the version and whether it was found.
-func tryReadGoDirective(buildInfo BuildInfo) (string, bool) {
+func tryReadGoDirective(buildInfo BuildInfo) (compilerVersion GoVersionInfo, toolchainVersion GoVersionInfo) {
 	if buildInfo.DepMode == GoGetWithModules {
-		versionRe := regexp.MustCompile(`(?m)^go[ \t\r]+([0-9]+\.[0-9]+(\.[0-9]+)?)$`)
+		versionRe := regexp.MustCompile(`(?m)^go[ \t\r]+([0-9]+\.[0-9]+(\.[0-9]+)?)`)
+		toolchainRe := regexp.MustCompile(`(?m)^toolchain[ \t\r]+go([0-9]+\.[0-9]+(\.[0-9]+)?)`)
 		goMod, err := os.ReadFile(filepath.Join(buildInfo.BaseDir, "go.mod"))
 		if err != nil {
 			log.Println("Failed to read go.mod to check for missing Go version")
 		} else {
 			matches := versionRe.FindSubmatch(goMod)
+			toolchainMatches := toolchainRe.FindSubmatch(goMod)
+
 			if matches != nil {
 				if len(matches) > 1 {
-					return string(matches[1]), true
+					compilerVersion = GoVersionInfo{string(matches[1]), true}
+				}
+			}
+
+			if toolchainMatches != nil {
+				if len(toolchainMatches) > 1 {
+					toolchainVersion = GoVersionInfo{string(toolchainMatches[1]), true}
 				}
 			}
 		}
 	}
-	return "", false
+
+	// If no `toolchain` directive is specified, Go assumes that its value is the same as that
+	// specified in a `go` directive
+	if !toolchainVersion.Found && compilerVersion.Found {
+		toolchainVersion = compilerVersion
+	}
+
+	return compilerVersion, toolchainVersion
 }
 
 // Returns the appropriate ModMode for the current project
@@ -771,13 +802,15 @@ func installDependenciesAndBuild() {
 		os.Setenv("GO111MODULE", "auto")
 	}
 
-	goModVersion, goModVersionFound := tryReadGoDirective(buildInfo)
+	goVersionInfo, _ := tryReadGoDirective(buildInfo)
 
-	if goModVersionFound && semver.Compare("v"+goModVersion, getEnvGoSemVer()) > 0 {
+	// This diagnostic is not required if the system Go version is 1.21 or greater, since the
+	// Go tooling should install required Go versions as needed.
+	if semver.Compare(getEnvGoSemVer(), "v1.21.0") < 0 && goVersionInfo.Found && semver.Compare("v"+goVersionInfo.Version, getEnvGoSemVer()) > 0 {
 		diagnostics.EmitNewerGoVersionNeeded()
 	}
 
-	fixGoVendorIssues(&buildInfo, goModVersionFound)
+	fixGoVendorIssues(&buildInfo, goVersionInfo.Found)
 
 	tryUpdateGoModAndGoSum(buildInfo)
 
@@ -1092,7 +1125,8 @@ func isGoInstalled() bool {
 func identifyEnvironment() {
 	var v versionInfo
 	buildInfo := getBuildInfo(false)
-	v.goModVersion, v.goModVersionFound = tryReadGoDirective(buildInfo)
+	goVersionInfo, _ := tryReadGoDirective(buildInfo)
+	v.goModVersion, v.goModVersionFound = goVersionInfo.Version, goVersionInfo.Found
 
 	v.goEnvVersionFound = isGoInstalled()
 	if v.goEnvVersionFound {

go/ql/integration-tests/all-platforms/go/diagnostics/newer-go-version-needed/diagnostics.expected

@@ -12,17 +12,3 @@
     "telemetry": true
   }
 }
-{
-  "markdownMessage": "The detected version of Go is lower than the version specified in `go.mod`. [Install a newer version](https://github.com/actions/setup-go#basic).",
-  "severity": "error",
-  "source": {
-    "extractorName": "go",
-    "id": "go/autobuilder/newer-go-version-needed",
-    "name": "Newer Go version needed"
-  },
-  "visibility": {
-    "cliSummaryTable": true,
-    "statusPage": true,
-    "telemetry": true
-  }
-}

go/ql/integration-tests/all-platforms/go/diagnostics/newer-go-version-needed/test.py

@@ -4,6 +4,6 @@ from create_database_utils import *
 from diagnostics_test_utils import *
 
 os.environ['LGTM_INDEX_IMPORT_PATH'] = "test"
-run_codeql_database_create([], lang="go", source="work", db=None)
+run_codeql_database_create([], lang="go", source="work", db=None, runFunction=runUnsuccessfully)
 
 check_diagnostics()

go/ql/integration-tests/all-platforms/go/diagnostics/newer-go-version-needed/work/go.mod

@@ -1,3 +1,3 @@
-go 999.0
+go 1.999.0
 
 module test