487aff421 Check subtree consistency in Travis (Pieter Wuille)
e1d0cc23a Improve git-subtree-check.sh (Pieter Wuille)
Pull request description:
Apparently many of our subtrees get modified by PRs in this repository, without getting noticed.
To improve upon this:
* Make git-subtree-check.sh capable of doing a weaker consistency check (that doesn't need access to external repositories), but which should be sufficient to detect unintended changes. It can be fooled by a fake subtree merge commit, but that would hopefully be obvious to reviewers.
* Make Travis invoke this subtree check for each of our subtrees.
Note that Travis is currently expected to fail on this PR, as 2 out of 4 subtrees (`src/secp156k1` and `src/univalue` have been modified directly in master).
Tree-SHA512: 465b680392d3daf38a8c1dda77d6f74b1d1c23324c378774777fb95aa673e119a8f7e3ccc124e41d97b5ac8975f3d79f3015797d2d309666582394364917ec4e
We have several pieces of information about subtrees:
1) What their current directory contents is
2) What their directory contents was at the time of the last subtree merge
3) What the directory contents of the upstream project is in the commit referred to by the subtree merge.
Normally, all 3 should be identical. git-subtree-check.sh so far only compared (1) with (3) however.
Fix this by comparing all three, and give some more useful diff output in the case of mismatch.
The added benefit is that (1) and (2) can be compared without needing to see the upstream repository.
