Top level dependencies don't show when it is already listed as a subdependency when freezing #161
Description
Not sure how common of a use case this is -
We have a script to verify the top level dependencies using pipdeptree. However, if a higher level dependency includes another dependency, the lower one is not listed as a top level dependency in the tree.
We can change our script to no longer do this, but was wondering if this was valid bug before proceeding.
It could also be a change in behavior in pip itself, but not sure.
The requirements.txt are slightly different, but future is listed as a top dependency in both files.
Simplest Example
pipdeptree 1.0.0 + Python2.7 (Notice that future is listed as a top dependency)
$ pipdeptree -w silence -f -p oic,future
future==0.18.2
oic==0.15.1
alabaster==0.7.12
Beaker==1.11.0
funcsigs==1.0.2
cryptography==3.3.2
cffi==1.14.5
pycparser==2.20
enum34==1.1.10
ipaddress==1.0.23
six==1.15.0
future==0.18.2
Mako==1.1.1
MarkupSafe==1.1.1
pycryptodomex==3.9.8
pyjwkest==1.4.2
future==0.18.2
pycryptodomex==3.9.8
requests==2.25.0
certifi==2021.5.30
chardet==3.0.4
idna==2.10
urllib3==1.26.5
six==1.15.0
requests==2.25.0
certifi==2021.5.30
chardet==3.0.4
idna==2.10
urllib3==1.26.5
six==1.15.0
$ pipdeptree -w silence -f -p future
future==0.18.2
pipdeptree 2.2.1 + python3.9
$ pipdeptree -w silence -f -p future,oic
oic==1.2.1
Beaker==1.11.0
cryptography==3.3.2
cffi==1.14.5
pycparser==2.20
six==1.15.0
defusedxml==0.6.0
Mako==1.1.3
MarkupSafe==2.0.1
pycryptodomex==3.9.8
pyjwkest==1.4.2
future==0.18.2
pycryptodomex==3.9.8
requests==2.26.0
certifi==2021.10.8
charset-normalizer==2.0.7
idna==3.3
urllib3==1.26.7
six==1.15.0
requests==2.26.0
certifi==2021.10.8
charset-normalizer==2.0.7
idna==3.3
urllib3==1.26.7
typing_extensions==4.0.1
$ pipdeptree -w silence -f -p future
future==0.18.2