cmd/go: improve pseudo-version timestamp error

The previous "invalid pseudo-version: does not match version-control
timestamp" error message used a different timestamp format than the
format used in go.mod and go.sum. For cut-and-paste-ability this patch
makes the two consistent.

Fixes #36974

Change-Id: I21f344ab9898cc584c0bcf4a75d74275a703c650
Reviewed-on: https://go-review.googlesource.com/c/go/+/217437
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Michael Matloob <matloob@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>

3 files changed, 7 insertions, 5 deletions

diff --git a/src/cmd/go/internal/modfetch/coderepo.go b/src/cmd/go/internal/modfetch/coderepo.go
index 753f65b3de..d043903336 100644
--- a/src/cmd/go/internal/modfetch/coderepo.go
+++ b/src/cmd/go/internal/modfetch/coderepo.go
@@ -563,7 +563,7 @@ func (r *codeRepo) validatePseudoVersion(info *codehost.RevInfo, version string)
 		return err
 	}
 	if !t.Equal(info.Time.Truncate(time.Second)) {
-		return fmt.Errorf("does not match version-control timestamp (%s)", info.Time.UTC().Format(time.RFC3339))
+		return fmt.Errorf("does not match version-control timestamp (expected %s)", info.Time.UTC().Format(pseudoVersionTimestampFormat))
 	}
 
 	tagPrefix := ""
diff --git a/src/cmd/go/internal/modfetch/pseudo.go b/src/cmd/go/internal/modfetch/pseudo.go
index 57dee11d07..20c0b060ab 100644
--- a/src/cmd/go/internal/modfetch/pseudo.go
+++ b/src/cmd/go/internal/modfetch/pseudo.go
@@ -48,6 +48,8 @@ import (
 
 var pseudoVersionRE = lazyregexp.New(`^v[0-9]+\.(0\.0-|\d+\.\d+-([^+]*\.)?0\.)\d{14}-[A-Za-z0-9]+(\+[0-9A-Za-z-]+(\.[0-9A-Za-z-]+)*)?$`)
 
+const pseudoVersionTimestampFormat = "20060102150405"
+
 // PseudoVersion returns a pseudo-version for the given major version ("v1")
 // preexisting older tagged version ("" or "v1.2.3" or "v1.2.3-pre"), revision time,
 // and revision identifier (usually a 12-byte commit hash prefix).
@@ -55,7 +57,7 @@ func PseudoVersion(major, older string, t time.Time, rev string) string {
 	if major == "" {
 		major = "v0"
 	}
-	segment := fmt.Sprintf("%s-%s", t.UTC().Format("20060102150405"), rev)
+	segment := fmt.Sprintf("%s-%s", t.UTC().Format(pseudoVersionTimestampFormat), rev)
 	build := semver.Build(older)
 	older = semver.Canonical(older)
 	if older == "" {
diff --git a/src/cmd/go/testdata/script/mod_invalid_version.txt b/src/cmd/go/testdata/script/mod_invalid_version.txt
index 76e0b43a73..7e1bc9ea4f 100644
--- a/src/cmd/go/testdata/script/mod_invalid_version.txt
+++ b/src/cmd/go/testdata/script/mod_invalid_version.txt
@@ -76,17 +76,17 @@ cp go.mod.orig go.mod
 go mod edit -require golang.org/x/text@v0.1.1-0.20190915032832-14c0d48ead0c
 cd outside
 ! go list -m golang.org/x/text
-stderr 'go: example.com@v0.0.0 requires\n\tgolang.org/x/text@v0.1.1-0.20190915032832-14c0d48ead0c: invalid pseudo-version: does not match version-control timestamp \(2017-09-15T03:28:32Z\)'
+stderr 'go: example.com@v0.0.0 requires\n\tgolang.org/x/text@v0.1.1-0.20190915032832-14c0d48ead0c: invalid pseudo-version: does not match version-control timestamp \(expected 20170915032832\)'
 cd ..
 ! go list -m golang.org/x/text
-stderr 'golang.org/x/text@v0.1.1-0.20190915032832-14c0d48ead0c: invalid pseudo-version: does not match version-control timestamp \(2017-09-15T03:28:32Z\)'
+stderr 'golang.org/x/text@v0.1.1-0.20190915032832-14c0d48ead0c: invalid pseudo-version: does not match version-control timestamp \(expected 20170915032832\)'
 
 # A 'replace' directive in the main module can replace an invalid timestamp
 # with a valid one.
 go mod edit -replace golang.org/x/text@v0.1.1-0.20190915032832-14c0d48ead0c=golang.org/x/text@14c0d48ead0c
 cd outside
 ! go list -m golang.org/x/text
-stderr 'go: example.com@v0.0.0 requires\n\tgolang.org/x/text@v0.1.1-0.20190915032832-14c0d48ead0c: invalid pseudo-version: does not match version-control timestamp \(2017-09-15T03:28:32Z\)'
+stderr 'go: example.com@v0.0.0 requires\n\tgolang.org/x/text@v0.1.1-0.20190915032832-14c0d48ead0c: invalid pseudo-version: does not match version-control timestamp \(expected 20170915032832\)'
 cd ..
 go list -m golang.org/x/text
 stdout 'golang.org/x/text v0.1.1-0.20190915032832-14c0d48ead0c => golang.org/x/text v0.1.1-0.20170915032832-14c0d48ead0c'