From: Russ Cox <rsc@golang.org>
Date: Sat, 11 Aug 2018 00:05:44 +0000 (-0400)
Subject: cmd/go: ignore import "C" files in module loader in non-cgo mode
X-Git-Tag: go1.11rc2~8^2~22
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=974d5364a643e107c4dea1df20293c67c32bfc04;p=gostls13.git

cmd/go: ignore import "C" files in module loader in non-cgo mode

Obviously, including files that import "C" when cgo is disabled is wrong.
The package load step correctly excludes them and finds no files at all,
which then causes a failure.

Fixes #26927.

Change-Id: I00e6d6450e783d467d20bde99e91240ecb0db837
Reviewed-on: https://go-review.googlesource.com/129062
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Reviewed-by: David du Colombier <0intro@gmail.com>
---

diff --git a/src/cmd/go/internal/imports/scan.go b/src/cmd/go/internal/imports/scan.go
index 095bb64a8d..bae6b934bc 100644
--- a/src/cmd/go/internal/imports/scan.go
+++ b/src/cmd/go/internal/imports/scan.go
@@ -37,6 +37,7 @@ func scanFiles(files []string, tags map[string]bool, explicitFiles bool) ([]stri
 	imports := make(map[string]bool)
 	testImports := make(map[string]bool)
 	numFiles := 0
+Files:
 	for _, name := range files {
 		r, err := os.Open(name)
 		if err != nil {
@@ -48,6 +49,12 @@ func scanFiles(files []string, tags map[string]bool, explicitFiles bool) ([]stri
 		if err != nil {
 			return nil, nil, fmt.Errorf("reading %s: %v", name, err)
 		}
+		// import "C" is implicit requirement of cgo tag
+		for _, path := range list {
+			if path == `"C"` && !tags["cgo"] && !tags["*"] {
+				continue Files
+			}
+		}
 		if !explicitFiles && !ShouldBuild(data, tags) {
 			continue
 		}
diff --git a/src/cmd/go/testdata/script/mod_patterns.txt b/src/cmd/go/testdata/script/mod_patterns.txt
index 36d738a867..a43fe82489 100644
--- a/src/cmd/go/testdata/script/mod_patterns.txt
+++ b/src/cmd/go/testdata/script/mod_patterns.txt
@@ -43,6 +43,10 @@ stdout example.com/m/useunsafe
 [cgo] stdout example.com/m/useC
 [!cgo] ! stdout example.com/m/useC
 
+env CGO_ENABLED=0
+go list -f '{{.ImportPath}}: {{.Match}}' all ... example.com/m/... ./... ./xyz...
+! stdout example.com/m/useC
+
 -- m/go.mod --
 module example.com/m