No mesh compatibility check on β when assigning Green's function defined by blocks

[Crampon16]

Description

When two Green's functions are defined by block (e.g. "up", "dn") and have different temperatures, assigning the content of one to the other does not raise an exception.

Steps to Reproduce

from triqs.gf import *

g1 = GfImFreq(beta=10, indices=[0])
g2 = GfImFreq(beta=20, indices=[0])

G1 = BlockGf(block_list=[g1,g1], name_list=['up','dn'], make_copies=True)
G2 = BlockGf(block_list=[g2,g2], name_list=['up','dn'], make_copies=True)

G1['up'] << G2['dn']  # complains
G1 << G2              # does not complain !!

Expected behavior: an Assertion Error because of mesh compatibility is raised

Actual behavior: G2's data is copied to G1, (without altering the original mesh's temperature).

Versions

You are using the TRIQS library version 3.0.0

You are using the git hash 

I am using MacOS Mojave v 10.14.6, and have also been able to reproduce on various Ubuntus.

Additional Information

Jupyter notebook to quickly reproduce the error: bug_no_beta_check.ipynb.zip

[the-hampel]

Dear @Crampon16, this is indeed a problem I would say. I don't see why this would be the desired behavior to overwrite the block gf with a different mesh. The problem is also existent in TRIQS 3.1.x and on the current unstable branch.

[Wentzell]

Fixed by d64d76754