check-code: forbid using bash in shebang Some platforms (ex. FreeBSD) do not have `bash` by default. Therefore it should not be used in test scripts. Differential Revision: https://phab.mercurial-scm.org/D609

amend: add tests for amending only some files from commit to be amended We do not have robust enough tests for scenarios where only some files in a changeset are amended. This presents an interesting scenario because the working copy could have modified versions of the remaining files in the pre-amend changeset. Therefore, I have added some tests to ensure that amend behaves as expected in these scenarios. Test Plan: Ensured that the test "test-commit-amend.t" passes. Differential Revision: https://phab.mercurial-scm.org/D596

test-editor-filename: fix portability of fake editor command - /bin/bash doesn't exist on FreeBSD - edit is executed by cmd.exe on Windows

amend: moving first assignment of newid closer to its use newid was needlessly further away from where its intended to be used leading to bad readability. This commit moves it to address the same. The end goal is to remove the redundant commit in the amend code path and this commit takes care of cleaning up some unrelated code before that change. Test Plan: ran the test suite Differential Revision: https://phab.mercurial-scm.org/D597

amend: rectify comment Comment was ambiguous as there can be two parents of a changeset in mercurial. This commit fixes the comment to clarify that the first parent is being considered. Test Plan: ran the test suite Differential Revision: https://phab.mercurial-scm.org/D595

amend: removing redundant if condition There is needless checking for the new commit hash not being equal to the old commit hash. This condition will always be true at this point in the code path and thus, can be removed safely. This commit removes the redundant condition. Test Plan: ran the test suite. Differential Revision: https://phab.mercurial-scm.org/D594

editor: file created for diff action should have .diff suffix This is a follow-up to https://phab.mercurial-scm.org/D464 (6e6452bc441d) that introduced the new file extension behavior. It erroneously changed `.diff` to `.diff.hg.txt`. Test Plan: Verified `make tests` passes, particularly `test-editor-filename.t`. Differential Revision: https://phab.mercurial-scm.org/D607

test-amend: match output using conditional test case name D466 (6cc8f848b4c3) allows output to be conditionally matched by test name. This patch changes test-amend.t to use that feature, instead of duplicating `hg amend` command or use `-q` to silence its output. Differential Revision: https://phab.mercurial-scm.org/D601