1# https://golang.org/issue/46141: 'go mod tidy' for a Go 1.17 module should by
2# default preserve enough checksums for the module to be used by Go 1.16.
3#
4# We don't have a copy of Go 1.16 handy, but we can simulate it by editing the
5# 'go' version in the go.mod file to 1.16, without actually updating the
6# requirements to match.
7
8[short] skip
9
10env MODFMT='{{with .Module}}{{.Path}} {{.Version}}{{end}}'
11
12
13# This module has the same module dependency graph in Go 1.16 as in Go 1.17,
14# but in 1.16 requires (checksums for) additional (irrelevant) go.mod files.
15#
16# The module graph under both versions looks like:
17#
18# m ---- example.com/version v1.1.0
19# |
20# + ---- example.net/lazy v0.1.0 ---- example.com/version v1.0.1
21#
22# Go 1.17 avoids loading the go.mod file for example.com/version v1.0.1
23# (because it is lower than the version explicitly required by m,
24# and the module that requires it — m — specifies 'go 1.17').
25#
26# That go.mod file happens not to affect the final 1.16 module graph anyway,
27# so the pruned graph is equivalent to the unpruned one.
28
29cp go.mod go.mod.orig
30go mod tidy
31cmp go.mod go.mod.orig
32
33go list -m all
34cmp stdout m_all.txt
35
36go mod edit -go=1.16
37go list -m all
38cmp stdout m_all.txt
39
40
41# If we explicitly drop compatibility with 1.16, we retain fewer checksums,
42# which gives a cleaner go.sum file but causes 1.16 to fail in readonly mode.
43
44cp go.mod.orig go.mod
45go mod tidy -compat=1.17
46cmp go.mod go.mod.orig
47
48go list -m all
49cmp stdout m_all.txt
50
51go mod edit -go=1.16
52! go list -m all
53stderr '^go: example.net/lazy@v0.1.0 requires\n\texample.com/version@v1.0.1: missing go.sum entry for go.mod file; to add it:\n\tgo mod download example.com/version$'
54
55
56-- go.mod --
57// Module m happens to have the exact same build list as what would be
58// selected under Go 1.16, but computes that build list without looking at
59// as many go.mod files.
60module example.com/m
61
62go 1.17
63
64replace example.net/lazy v0.1.0 => ./lazy
65
66require (
67 example.com/version v1.1.0
68 example.net/lazy v0.1.0
69)
70-- m_all.txt --
71example.com/m
72example.com/version v1.1.0
73example.net/lazy v0.1.0 => ./lazy
74-- compatible.go --
75package compatible
76
77import (
78 _ "example.com/version"
79 _ "example.net/lazy"
80)
81-- lazy/go.mod --
82// Module lazy requires example.com/version v1.0.1.
83//
84// However, since this module is lazy, its dependents
85// should not need checksums for that version of the module
86// unless they actually import packages from it.
87module example.net/lazy
88
89go 1.17
90
91require example.com/version v1.0.1
92-- lazy/lazy.go --
93package lazy
94
95import _ "example.com/version"
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