[BUG] npm update changing package.json

[mattpen]

Current Behavior:

npm update will make changes to package.json, even if --save=false or --no-save is present. This includes adding a newline to the end of package.json even if no other changes were present.

Expected Behavior:

If save is set to false, npm update should not modify package.json

Steps To Reproduce:

I see this same behavior with npm config set save false, npm update --no-save, and npm update --save=false.

$ echo -n {} | cat > package.json
$ cat package.json               
{}%                                                                                                  
$ npm config get save            
false
$ npm update                     

up to date, audited 1 package in 151ms

found 0 vulnerabilities
$ cat package.json               
{}
$

Environment:

• OS: MacOS 11.2.3 (M1)
• Node: 15.9.0
• npm: 7.5.3

[ZwapKillrath]

Related to #708?

[darcyclarke]

@mattpen can't seem to reproduce; Can you try updating to latest (npm i -g npm should be v7.9.0)

[mattpen]

@darcyclarke - I just upgraded and I still get the same results (npm update inserts trailing newline into package.json) with v7.9.0.

$ echo -n {} | cat > package.json
$ cat package.json
{}%
$ npm config get save
false
$ npm update

up to date, audited 1 package in 158ms

found 0 vulnerabilities
$ cat package.json 
{}
$ npm -v
7.9.0
$ 

[mattpen]

Using node 14 or 16 this problem does not occur.

[ruyadorno]

#4223 cleans up the usage of save config in npm update

Closing this issue since the original problem should be fixed in npm@8.3.2