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
10 env 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
29 cp go.mod go.mod.orig
30 go mod tidy
31 cmp go.mod go.mod.orig
32
33 go list -m all
34 cmp stdout m_all.txt
35
36 go mod edit -go=1.16
37 go list -m all
38 cmp 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
44 cp go.mod.orig go.mod
45 go mod tidy -compat=1.17
46 cmp go.mod go.mod.orig
47
48 go list -m all
49 cmp stdout m_all.txt
50
51 go mod edit -go=1.16
52 ! go list -m all
53 stderr '^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.
60 module example.com/m
61
62 go 1.17
63
64 replace example.net/lazy v0.1.0 => ./lazy
65
66 require (
67 example.com/version v1.1.0
68 example.net/lazy v0.1.0
69 )
70 -- m_all.txt --
71 example.com/m
72 example.com/version v1.1.0
73 example.net/lazy v0.1.0 => ./lazy
74 -- compatible.go --
75 package compatible
76
77 import (
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.
87 module example.net/lazy
88
89 go 1.17
90
91 require example.com/version v1.0.1
92 -- lazy/lazy.go --
93 package lazy
94
95 import _ "example.com/version"
96
View as plain text