$ cat .composer/config.json
{ "repositories": {
"a": {
"type": "path",
"url": "repo/a"
},
"b": {
"type": "path",
"url": "repo/b"
},
"c": {
"type": "path",
"url": "repo/c"
}
}
} $ cat repo/a/composer.json
{ "name": "my/a",
"require": {
"my/b": "dev-master"
}
} $ cat repo/b/composer.json
{ "name": "my/b",
"require": {
"my/c": "dev-master"
}
} $ cat repo/c/composer.json
{ "name": "my/c"
}

How do you see

my/a requires my/b
my/b requires my/c

But I wanted to know if there is a way to view *quickly* the whole
structure of dependences.
Above all, I would like to know the *dependents*.

I tried like this

$ COMPOSER_HOME=.composer composer show -a my/b
No composer.json found in the current directory, showing available
packages from a, b, c, packagist.org
name : my/b
descrip. :
keywords :
versions : dev-master
type : library
homepage :
source : []
dist : [path] repo/b 6de0f9e677dcab7051f94dbbf05893d0165bb826
names : my/b

requires
my/c dev-master

In summary

$ COMPOSER_HOME=.composer composer show -a my/b \
| grep my/
No composer.json found in the current directory, showing available
packages from a, b, c, packagist.org
name : my/b
names : my/b
my/c dev-master

It tell me that

my/b requires my/c

but it doesn't tell me that

my/b is required from my/a (this is the thing that interests me most).

For example, if I have to remove a package (obsolete package), how can I
verify that it does not have dependents?

SupaPlex:

[...]
> For example, if I have to remove a package (obsolete package), how can I
> verify that it does not have dependents?

You can try: composer show --tree

--
Arno Welzel
https://arnowelzel.de

Il 22/06/22 14:33, Arno Welzel ha scritto:
> SupaPlex:
>
> [...]
>> For example, if I have to remove a package (obsolete package), how can I
>> verify that it does not have dependents?
>
> You can try: composer show --tree
>
>
>
>

Composer could not find a composer.json file
To initialize a project, please create a composer.json file as described
in the https://getcomposer.org/ "Getting Started" section

SupaPlex:

> Il 22/06/22 14:33, Arno Welzel ha scritto:
>> SupaPlex:
>>
>> [...]
>>> For example, if I have to remove a package (obsolete package), how can I
>>> verify that it does not have dependents?
>>
>> You can try: composer show --tree
>>
>>
>>
>>
>
> Composer could not find a composer.json file
> To initialize a project, please create a composer.json file as described
> in the https://getcomposer.org/ "Getting Started" section

Why do you try to use Composer outside a folder with composer.json?

Of course you need to call this inside repo/a, repo/b and repo/c.

--
Arno Welzel
https://arnowelzel.de

Il 22/06/22 16:07, Arno Welzel ha scritto:
> Why do you try to use Composer outside a folder with composer.json?

why shouldn't I do it?

SupaPlex:

> Il 22/06/22 16:07, Arno Welzel ha scritto:
>> Why do you try to use Composer outside a folder with composer.json?
>
> why shouldn't I do it?

Because composer.json is the file where your dependencies are defined.

Also see: <https://getcomposer.org/doc/01-basic-usage.md>

--
Arno Welzel
https://arnowelzel.de

Il 22/06/22 16:37, Arno Welzel ha scritto:
> SupaPlex:
>
>> Il 22/06/22 16:07, Arno Welzel ha scritto:
>>> Why do you try to use Composer outside a folder with composer.json?
>>
>> why shouldn't I do it?
>
> Because composer.json is the file where your dependencies are defined.
>
> Also see: <https://getcomposer.org/doc/01-basic-usage.md>
>
>

What dependencies should i define?
The info I want is for packages global level, not for single project
(*/composer.json).

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SupaPlex:

> Il 22/06/22 16:37, Arno Welzel ha scritto:
>> SupaPlex:
>>
>>> Il 22/06/22 16:07, Arno Welzel ha scritto:
>>>> Why do you try to use Composer outside a folder with composer.json?
>>>
>>> why shouldn't I do it?
>>
>> Because composer.json is the file where your dependencies are defined.
>>
>> Also see: <https://getcomposer.org/doc/01-basic-usage.md>
>>
>>
>
> What dependencies should i define?
> The info I want is for packages global level, not for single project
> (*/composer.json).

There is no "global" level.

Each composer.json defines the dependencies for that very project. There
are no "global" dependencies covering multiple projects. If a project
wants to uses a component, it *must* have a reference for that in
composer.json. The specific version used when installing the components
using "composer install" are then recorded in composer.lock.

--
Arno Welzel
https://arnowelzel.de