share: rework config options to be much clearer and easier Recently I implemented various boolean configs which control how to behave when there is a share-safe mismatch between source and share repository. Mismatch means that source supports share-safe where as share does not or vice versa. However, while discussion and documentation we realized that it's too complicated and there are some combinations of values which makes no sense. We decided to introduce a config option with 4 possible values which makes controlling and understanding things easier. The config option `share.safe-mismatch.source-{not-}safe` can have following 4 values: * abort (default): error out if there is mismatch * allow: allow to work with respecting share source configuration * {up|down}grade-abort: try to {up|down}grade, if it fails, abort * {up|down}grade-allow: try to {up|down}grade, if it fails, continue in allow mode I am not sure if I can explain 3 config options which I deleted right now in just 5 lines which is a sign of how complex they became. No test changes demonstrate that functionality is same, only names have changed. Differential Revision: https://phab.mercurial-scm.org/D9785

localrepo: disallow share if there is a version mismatch by default Earlier we used to allow shares which don't use share-safe mechanism to access repository which uses share-safe mechanism. This defeats the purpose and is bad behavior. This patch disallows that. Next patch will introduce a config option to allow that and have clearer understanding around various options. Differential Revision: https://phab.mercurial-scm.org/D9784

upgrade: re-read current requirements after taking lock Since we are writing to repository, it's better to re-read after taking the lock. Differential Revision: https://phab.mercurial-scm.org/D9822

upgrade: take lock only for part where it's required The final config calculation code does not require a lock, only writing it back does require one. Differential Revision: https://phab.mercurial-scm.org/D9783