From: Russ Cox <rsc@golang.org>
Date: Thu, 1 Jun 2023 18:11:27 +0000 (-0400)
Subject: cmd/go: add gover.Max and gover.MaxToolchain
X-Git-Tag: go1.21rc1~123
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=936ce874ace0bed17eac20dfa21fe04a45d30603;p=gostls13.git

cmd/go: add gover.Max and gover.MaxToolchain

I've inlined these by hand enough times now.

For #57001.

Change-Id: Ia274bd444f12b07ce14eeb2b5a66546880db8f77
Reviewed-on: https://go-review.googlesource.com/c/go/+/499982
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Bryan Mills <bcmills@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Russ Cox <rsc@golang.org>
---

diff --git a/src/cmd/go/internal/gover/gover.go b/src/cmd/go/internal/gover/gover.go
index fbea612227..247717125b 100644
--- a/src/cmd/go/internal/gover/gover.go
+++ b/src/cmd/go/internal/gover/gover.go
@@ -55,6 +55,26 @@ func Compare(x, y string) int {
 	return 0
 }
 
+// Max returns the maximum of x and y interpreted as toolchain versions,
+// compared using Compare.
+// If x and y compare equal, Max returns x.
+func Max(x, y string) string {
+	if Compare(x, y) < 0 {
+		return y
+	}
+	return x
+}
+
+// Toolchain returns the maximum of x and y interpreted as toolchain names,
+// compared using Compare(FromToolchain(x), FromToolchain(y)).
+// If x and y compare equal, Max returns x.
+func ToolchainMax(x, y string) string {
+	if Compare(FromToolchain(x), FromToolchain(y)) < 0 {
+		return y
+	}
+	return x
+}
+
 // IsLang reports whether v denotes the overall Go language version
 // and not a specific release. Starting with the Go 1.21 release, "1.x" denotes
 // the overall language version; the first release is "1.x.0".
diff --git a/src/cmd/go/internal/modget/get.go b/src/cmd/go/internal/modget/get.go
index 0cf3c1dc84..8a8b8dea22 100644
--- a/src/cmd/go/internal/modget/get.go
+++ b/src/cmd/go/internal/modget/get.go
@@ -1233,8 +1233,8 @@ func (r *resolver) resolveQueries(ctx context.Context, queries []*query) (change
 		goVers := ""
 		for _, q := range queries {
 			for _, cs := range q.candidates {
-				if e := (*gover.TooNewError)(nil); errors.As(cs.err, &e) && gover.Compare(goVers, e.GoVersion) < 0 {
-					goVers = e.GoVersion
+				if e := (*gover.TooNewError)(nil); errors.As(cs.err, &e) {
+					goVers = gover.Max(goVers, e.GoVersion)
 				}
 			}
 		}