[release-branch.go1.21] cmd/go: fix missing case checking for empty slice

When we were comparing the first element of import stacks when sorting
depserrors we checked if the first stack was non empty, but not the
second one. Do the check for both stacks.

Fixes #61818
Updates #61816
For #59905

Change-Id: Id5c11c2b1104eec93196a08c53372ee2ba97c701
Reviewed-on: https://go-review.googlesource.com/c/go/+/516739
Reviewed-by: Bryan Mills <bcmills@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Michael Matloob <matloob@golang.org>
(cherry picked from commit 58447d757c233f2a9c3c5a73e2d96a6885f2759a)
Reviewed-on: https://go-review.googlesource.com/c/go/+/519658
Reviewed-by: Michael Matloob <matloob@golang.org>
Run-TryBot: Bryan Mills <bcmills@google.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@google.com>

diff --git a/src/cmd/go/internal/list/list.go b/src/cmd/go/internal/list/list.go
index 79120e6a99678576b7d9a4751cc3bb81d48b09c6..92020da946ad74144dba45d56e7b0959b14c5341 100644 (file)
--- a/src/cmd/go/internal/list/list.go
+++ b/src/cmd/go/internal/list/list.go
@@ -959,7 +959,10 @@ func collectDepsErrors(p *load.Package) {
                        if len(stkj) != 0 {
                                return true
                        }
+
                        return p.DepsErrors[i].Err.Error() < p.DepsErrors[j].Err.Error()
+               } else if len(stkj) == 0 {
+                       return false
                }
                pathi, pathj := stki[len(stki)-1], stkj[len(stkj)-1]
                return pathi < pathj

diff --git a/src/cmd/go/testdata/script/list_issue_59905.txt b/src/cmd/go/testdata/script/list_issue_59905.txt
index 74804625998501b2080da6e4df39d9049b41f172..48c40d0d14599b1df6e94e837f4cd24ec66ed5d6 100644 (file)
--- a/src/cmd/go/testdata/script/list_issue_59905.txt
+++ b/src/cmd/go/testdata/script/list_issue_59905.txt
@@ -1,8 +1,13 @@
 # Expect no panic
 go list -f '{{if .DepsErrors}}{{.DepsErrors}}{{end}}' -export -e -deps
-cmpenv stdout wanterr
+cmpenv stdout wanterr_59905
 
--- wanterr --
+# Expect no panic (Issue 61816)
+cp level1b_61816.txt level1b/pkg.go
+go list -f '{{if .DepsErrors}}{{.DepsErrors}}{{end}}' -export -e -deps
+cmpenv stdout wanterr_61816
+
+-- wanterr_59905 --
 [# test/main/level1a
 level1a${/}pkg.go:5:2: level2x redeclared in this block
        level1a${/}pkg.go:4:2: other declaration of level2x
@@ -14,6 +19,23 @@ level1b${/}pkg.go:5:2: level2x redeclared in this block
 level1b${/}pkg.go:5:2: "test/main/level1b/level2y" imported as level2x and not used
 level1b${/}pkg.go:8:39: undefined: level2y
 ]
+-- wanterr_61816 --
+[level1b${/}pkg.go:4:2: package foo is not in std ($GOROOT${/}src${/}foo)]
+[# test/main/level1a
+level1a${/}pkg.go:5:2: level2x redeclared in this block
+       level1a${/}pkg.go:4:2: other declaration of level2x
+level1a${/}pkg.go:5:2: "test/main/level1a/level2y" imported as level2x and not used
+level1a${/}pkg.go:8:39: undefined: level2y
+ level1b${/}pkg.go:4:2: package foo is not in std ($GOROOT${/}src${/}foo)]
+-- level1b_61816.txt --
+package level1b
+
+import (
+       "foo"
+)
+
+func Print() { println(level2x.Value, level2y.Value) }
+
 -- go.mod --
 module test/main