From: Bryan C. Mills <bcmills@google.com>
Date: Wed, 5 Aug 2020 03:53:01 +0000 (-0400)
Subject: cmd/go/internal/mvs: indicate the actual version when printing a mismatched ModuleError
X-Git-Tag: go1.16beta1~1228
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=c777863f77bb77be2e6c336b78dee2089647ff0e;p=gostls13.git

cmd/go/internal/mvs: indicate the actual version when printing a mismatched ModuleError

Previously, we suppressed the module version annotation if the last
error in the stack was a *module.ModuleError, regardless of its path.
However, if the error is for a replacement module, that produces a
confusing error message: the error is attributed to the last module in
the error path, but actually originates in the replacement (which is
not otherwise indicated).

Now, we print both the original and the replacement modules when they
differ, which may add some unfortunate redundancy in the output but at
least doesn't drop the very relevant information about replacements.

Fixes #35039

Change-Id: I631a7398033602b1bd5656150a4fad4945a87ade
Reviewed-on: https://go-review.googlesource.com/c/go/+/247765
Reviewed-by: Jay Conrod <jayconrod@google.com>
---

diff --git a/src/cmd/go/internal/mvs/errors.go b/src/cmd/go/internal/mvs/errors.go
index 8577902878..5564965fb5 100644
--- a/src/cmd/go/internal/mvs/errors.go
+++ b/src/cmd/go/internal/mvs/errors.go
@@ -78,16 +78,21 @@ func (e *BuildListError) Error() string {
 		b.WriteString(e.Err.Error())
 	} else {
 		for _, elem := range stack[:len(stack)-1] {
-			fmt.Fprintf(b, "%s@%s %s\n\t", elem.m.Path, elem.m.Version, elem.nextReason)
+			fmt.Fprintf(b, "%s %s\n\t", elem.m, elem.nextReason)
 		}
 		// Ensure that the final module path and version are included as part of the
 		// error message.
 		m := stack[len(stack)-1].m
-		if _, ok := e.Err.(*module.ModuleError); ok {
-			// TODO(bcmills): Also ensure that the module path and version match.
-			// (Otherwise, we may be reporting an error from a replacement without
-			// indicating the replacement path.)
-			fmt.Fprintf(b, "%v", e.Err)
+		if mErr, ok := e.Err.(*module.ModuleError); ok {
+			actual := module.Version{Path: mErr.Path, Version: mErr.Version}
+			if v, ok := mErr.Err.(*module.InvalidVersionError); ok {
+				actual.Version = v.Version
+			}
+			if actual == m {
+				fmt.Fprintf(b, "%v", e.Err)
+			} else {
+				fmt.Fprintf(b, "%s (replaced by %s): %v", m, actual, mErr.Err)
+			}
 		} else {
 			fmt.Fprintf(b, "%v", module.VersionError(m, e.Err))
 		}
diff --git a/src/cmd/go/testdata/script/mod_load_replace_mismatch.txt b/src/cmd/go/testdata/script/mod_load_replace_mismatch.txt
index 74dbb34b8a..067e209b01 100644
--- a/src/cmd/go/testdata/script/mod_load_replace_mismatch.txt
+++ b/src/cmd/go/testdata/script/mod_load_replace_mismatch.txt
@@ -18,6 +18,6 @@ package use
 import _ "rsc.io/quote"
 
 -- want --
-go: example.com/quote@v1.5.2: parsing go.mod:
+go: rsc.io/quote@v1.5.2 (replaced by example.com/quote@v1.5.2): parsing go.mod:
 	module declares its path as: rsc.io/Quote
 	        but was required as: rsc.io/quote
diff --git a/src/cmd/go/testdata/script/mod_replace_gopkgin.txt b/src/cmd/go/testdata/script/mod_replace_gopkgin.txt
index 28c1196284..674c99cb0c 100644
--- a/src/cmd/go/testdata/script/mod_replace_gopkgin.txt
+++ b/src/cmd/go/testdata/script/mod_replace_gopkgin.txt
@@ -34,7 +34,7 @@ go list -m gopkg.in/src-d/go-git.v4
 # A mismatched gopkg.in path should not be able to replace a different major version.
 cd ../3-to-gomod-4
 ! go list -m gopkg.in/src-d/go-git.v3
-stderr '^go: gopkg\.in/src-d/go-git\.v3@v3.0.0-20190801152248-0d1a009cbb60: invalid version: go\.mod has non-\.\.\.\.v3 module path "gopkg\.in/src-d/go-git\.v4" at revision 0d1a009cbb60$'
+stderr '^go: gopkg\.in/src-d/go-git\.v3@v3\.2\.0 \(replaced by gopkg\.in/src-d/go-git\.v3@v3\.0\.0-20190801152248-0d1a009cbb60\): version "v3\.0\.0-20190801152248-0d1a009cbb60" invalid: go\.mod has non-\.\.\.\.v3 module path "gopkg\.in/src-d/go-git\.v4" at revision 0d1a009cbb60$'
 
 -- 4-to-4/go.mod --
 module golang.org/issue/34254