Change Boost min version to 1.56

[cvvergara]

Problem

1. Due to 1.53, 1.54, 1.55 Boost's geometry lack of some functionality,
   Code from boost had to be ported to pgRouting repository here
2. Boost Graph which is used intensively evolves rapidly with new functions that can be added to pgRouting. Normally GSoC students choose which functions from Boost Graph to implement which might not be on the minimum version.

Improvement

As the continuation of #1817 (which is porting the changes from #1831)
For 3.2:

• Change Boost min version to 1.56

• If a Boost version 1.X does not have provide the requirements of a pgRouting function pgr_foo then:

  • The pgr_foo SQL code needs to return an error message stating which minimum version of Boost is needed to work
  • functions that exist and work on pgRouting 3.1should continue working on 3.2

• While Boost min version is less than 1.75

  • C++ standard to be the same minimum as required in Boost graph / geometry
    • C++ standard for pgRouting = max(BoostMin_Graph, BoostMin_Geometry)
    • example, for 1.75, boost graph needs c++03 and boost Geometry needs c++14, so C++14 is the version to use for Boost1.75
  • see this discussion
  • see this deprecation PR

• TODO (what I can think as global things at this moment in time)

  • set actions for Boost min version to start from 1.56
  • remove boost code copy of the repository
  • Set conditional testing on functions based on Boost versions
  • Set code to be compiled based on Boost version
  • Make functions to return error when the needed boost version does not exist
  • Document changes

[chenrui333]

👋 just heads up, due to the boost compatibility issue, I have closed the pgrouting 3.1.2 upgrade in the homebrew side.

[sanak]

@chenrui333
Thanks for information and sorry for closing the following issue on the Homebrew/homebrew-core repository...

• pgRouting remove unnecessary dependencies and flag, and fix license Homebrew/homebrew-core#67260

@dkastl @cvvergara (CC: @chenrui333)
Could you check whether pgRouting license is GPL-2.0-only or GPL-2.0-or-later ?
(Related with Homebrew/homebrew-core#69231.)

Well, about pgRouting Homebrew update, brew audit --strict pgrouting reported the following, but should we apply GPL-2.0-only or GPL-2.0-or-later ?

$ brew audit --strict pgrouting
:
pgrouting:
  * Formula pgrouting contains deprecated SPDX licenses: ["GPL-2.0"].
    You may need to add `-only` or `-or-later` for GNU licenses (e.g. `GPL`, `LGPL`, `AGPL`, `GFDL`).
    For a list of valid licenses check: https://spdx.org/licenses/
Error: 1 problem in 1 formula detected

[chenrui333]

yeah, the licensing thing is based on my interpretation with the license header declarations.

[chenrui333]

@sanak regarding closing the PR (I am not quite sure what would be the boost library that I can use with for pgrouting 3.1.2)

[sanak]

@chenrui333
Well, latest (=current) boost 1.75.0 is not compatible with current released pgRouting 3.1.2, so I think that the followings are possible.

• Quick: depends not boost (latest), but [email protected]
• Not quick but quite soon: wait for next pgRouting 3.1.3

The fix was already merged, so we can build it without changes by brew install --HEAD pgrouting.

• homebrew - install pgrouting #795 (comment)

[chenrui333]

yeah, I can give a try with [email protected] and then wait for the next release for pgrouting 3.1.3. :)

[chenrui333]

[email protected] is disabled, so i have to wait for the next release.

[cvvergara]

Changes done:

if the boost version >= "1.75.0"
   Use c++14 standard
else   
    Set to use c++11 if the compiler supports it
    else Set to use c++0x if the compiler supports it
    else Use the compiler as is. For example on MSVC 

[chenrui333]

yeah, I can give a try with [email protected] and then wait for the next release for pgrouting 3.1.3. :)

3.1.3 works for me and merged in Homebrew/homebrew-core#69644