filemerge: use leverage `util.readfile()` in `_maketempfiles()` Differential Revision: https://phab.mercurial-scm.org/D12191

filemerge: move removal of `.orig` extension on temp file close to context The place where the `.orig` extension is removed in `_maketempfiles()` doesn't make it clear that it's the backup path, which is why we have a comment in the code explaining it. Let's instead move it out of the function and close to where we get it from `backup.path()`, so that becomes clear. Differential Revision: https://phab.mercurial-scm.org/D12190

filemerge: remove `uselocalpath` argument from `_maketempfiles()` The `localpath` argument is unused if `uselocalpath` is false, so we can use `None` as a sentinel value for the variable instead and remove extra `uselocalpath` argument. That's not much of a win, but it's a small step towards further improvements. Differential Revision: https://phab.mercurial-scm.org/D12189

filemerge: remove an unnecessary join with absolute path The `backup` path is now always absolute, so we don't need to join it with the working copy path. Differential Revision: https://phab.mercurial-scm.org/D12188

filemerge: when using in-memory merge, always put backup files in temp dir Before calling a merge tool, we create a backup of the local side of the merge. That file can be put in the working copy or in a temporary directory, depending on the user's config. When we're merging in memory, we don't want to write to the actual, on-disk working copy, so we write the file to the in-memory working copy instead. However, since we don't support external merge tools with in-memory merge, it makes no difference where the file is actually stored (and if we ever do add support for external merge tools, then the file clearly can't live in the in-memory working-copy object anyway). So, since it doesn't matter where the file is stored, we can simplify by always putting them in the system's temp directory. Differential Revision: https://phab.mercurial-scm.org/D12187

filemerge: remove unused `repo` argument from `_maketempfiles()` I missed this in D12171. Differential Revision: https://phab.mercurial-scm.org/D12194

upgrade: make dirstate-v2 format variant compatible with share This only affects the dirstate and is safe to upgrade in the share. Differential Revision: https://phab.mercurial-scm.org/D12197

upgrade: prepare code (and output) for the idea of upgrading share This would work for a subset of action only. Our first target is dirstate-v2. Differential Revision: https://phab.mercurial-scm.org/D12196

sparse: add timing block for parsing sparse configs This was showing up in an operation I was doing today, and I'd like to be able to get trace spans for it instead of just profiler samples. Differential Revision: https://phab.mercurial-scm.org/D12186

narrowspec: add timing block for validating narrowspec This was showing up in an operation I was doing today, and I'd like to be able to get trace spans for it instead of just profiler samples. Differential Revision: https://phab.mercurial-scm.org/D12185