test-copies: add a "change during merge" variant to the A+E test Checks inline comment for details.

test-copies: filter out the linkrev part of `debugindex` It is not really useful for the tests and is a large source of churn when adding more revisions to the tests. Differential Revision: https://phab.mercurial-scm.org/D10050

test-copies: use "case-id" instead of revision number when listing sidedata The revision number are not very informative and can change when new changeset are added, creating unnecessary churn. We change the template before adding more test to improve clarify of the over changesets. Differential Revision: https://phab.mercurial-scm.org/D10049

patch: fix a formatting issue Differential Revision: https://phab.mercurial-scm.org/D10079

log: fix handling of root (or empty) path provided by matcher (issue6478) Since 27d6956d386b "match: use '' instead of '.' for root directory", '.' should be translated to ''. We can't blame repo.file() about this because an empty string is invalid as a file path, but I found at least two callers (_makematcher() and revset.filelog()) would crash because of this path[0]. So let's make repo.file() accept an empty string. path[0] == b'/' wouldn't work on Python 3 anyways.

tests: accept output changes by 33350debb480 Differential Revision: https://phab.mercurial-scm.org/D10067

test-copies: remove revision number from log Differential Revision: https://phab.mercurial-scm.org/D10048

test-copies: add test chaining multiple merge Right now, the copy tracing logic take the right decision for merges, but it does not keep track of the right information about these decision and can fall into later traps. We start with highlighting this possibility by adding new tests, and we will fix them later. Check the inline test documentation for details. Differential Revision: https://phab.mercurial-scm.org/D9611

test-copies: add test chaining multiple merges Right now, the copy tracing logic take the right decision for merges, but it does not keep track of the right information about these decision and can fall into later traps. We start with highlighting this possibility by adding new tests, and we will fix them later. Check the inline test documentation for details. Differential Revision: https://phab.mercurial-scm.org/D9610

test-copies: add test chaining multiple merges Right now, the copy tracing logic take the right decision for merges, but it does not keep track of the right information about these decision and can fall into later traps. We start with highlighting this possibility by adding new tests, and we will fix them later. Check the inline test documentation for details. Differential Revision: https://phab.mercurial-scm.org/D9609

test-copies: add subcase titles for various "conflicting" information variant This make the transitions between case clearer. Differential Revision: https://phab.mercurial-scm.org/D10047

test-copies: improve description of the B+F case This will make its role clearer. Differential Revision: https://phab.mercurial-scm.org/D10046

test-copies: improve description of the C+H case This will make its role clearer. Differential Revision: https://phab.mercurial-scm.org/D10045

test-copies: improve description of the B+C "revert/restore" case This will make its role clearer. Differential Revision: https://phab.mercurial-scm.org/D10044

test-copies: improve description of the G+C case This will make its role clearer. Differential Revision: https://phab.mercurial-scm.org/D10043

test-copies: improve description of the G+F case This will make its role clearer. Differential Revision: https://phab.mercurial-scm.org/D10042

test-copies: improve description of the D+G case This will make its role clearer. Differential Revision: https://phab.mercurial-scm.org/D10041

test-copies: improve description of the A+E case This will make its role clearer. Differential Revision: https://phab.mercurial-scm.org/D10040

test-copies: improve description of the B+D case This will make its role clearer. Differential Revision: https://phab.mercurial-scm.org/D10039

test-copies: improve description of the B+C case This will make its role clearer. Differential Revision: https://phab.mercurial-scm.org/D10038

test-copies: improve description of the A+B case This will make its role clearer. Differential Revision: https://phab.mercurial-scm.org/D10037

test-copies: use intermediate variable some commit descriptions Right now, everything mostly says "simple merge", we want to use something a bit more descriptive. Before doing any changes, we do most of the churn. This helps the next sets of changesets to be clearer. Differential Revision: https://phab.mercurial-scm.org/D10036

test-copies: don't use empty file for "same content" cases For main case (using filelog or sidedata), this lead to the following hash change. Changesets: - 01c2f5eabdc4ce2bdee42b5f86311955e6c8f573 → 319179230cc87769ab3a861ebffe7a534ebb3d85 - 01c2f5eabdc4 → 319179230cc8 - c72365ee036fca4fb27fd745459bfb6ea1ac6993 → 6cbc9c2b7b391dd738603173717c601648d3735f - c72365ee036f → 6cbc9c2b7b39 File revision for `f`: - 0dd616bc7ab1a111921d95d76f69cda5c2ac539c → cedeacc5bf5d9b9be4d7f8394d33a5349bb29c6e - 0dd616bc7ab1 → cedeacc5bf5d - eb806e34ef6be4c264effd5933d31004ad15a793 → ffb76cd765422a18759a335d8a81fa2bd455be6b - eb806e34ef6b → ffb76cd76542 - 6da5a2eecb9c833f830b67a4972366d49a9a142c → 08d1ff5926fbd0285cdeb044cbe8ab651687e86a - 6da5a2eecb9c → 08d1ff5926fb File revision for `d`: - 7bded9d9da1f7bf9bf7cbfb24fe1e6ccf68ec440 → ba177bbb45ea930ee48469a55d40224537bd57a9 For the "extra in changeset" case we get the following change for file `d`: - 68d5bca9df0577b6bc2ea30ca724e13ead60da81 → b894de5c94aadcb4894ea7c358389819c27fbcce - 68d5bca9df05 → b894de5c94aa - b80de5d138758541c5f05265ad144ab9fa86d1db → 56647659eff080e06e45c18ea9e848836dadea71 - b80de5d13875 → 56647659eff0

narrow: fix flaky behavior described in issue6150 This has been plaguing the CI for a good while, and it doesn't appear to have an easy fix proposed yet. The solution in this change is to always do an unambiguous (but expensive) lookup in case of comparison. This should always be correct, albeit suboptimal. Differential Revision: https://phab.mercurial-scm.org/D10034

patch: make diff --git to differentiate b/w file is empty or doesn't exists Before this patch, as we didn't differentiate the two cases of a file in a context: 1. File doesn't exists 2. File is empty which causes the blob id to be same for both the cases. Now we use `nullhex` for a file which doesn't exists in a context (aligning it with the git diff format) Changes in test file reflect the fixed behavior. Differential Revision: https://phab.mercurial-scm.org/D10001

tests: add a test to demonstrate a bug in `hg diff --git` (issue6486) Issue url: https://bz.mercurial-scm.org/show_bug.cgi?id=6486 This will be fixed in next patch. Differential Revision: https://phab.mercurial-scm.org/D10000

test-copies: reinstall initial identical (empty) files for chained copied This effectively back out changeset deeb215be337. Changeset deeb215be33 does not really include a justification for its change and make mes uncomfortable. I have been thinking about it and they are two options: - either having empty/full files does not make a difference, and deeb215be337 is a gratuitous changes. - either having empty/full files do make a difference and deeb215be33 silently change the test coverage. In such situation if we want the "not empty" case to be tested, we should add new cases to cover them In practice, we know that the "file content did not change, but merge still need to create a new filenode" case exists (for example if merging result in similar content but both parent of the file need to be recorded), and that such case are easy to miss/mess-up in the tests. Having all the file using the same (empty) content was done on purpose to increase the coverage of such corner case. As a result I am reinstalling the previous test situation. To increase the coverage of some case involving content-merge in test-copies-chain-merge.t, we will add a new, dedicated, cases later in this series, once various cleanup and test improvement have been set in place. This changeset starts with reinstalling the previous situation as (1) it is more fragile, so I am more confided getting it back in the initial situation, (2) I have specific test further down the line that are base on these one. The next changeset will slightly alter the test to use non-empty files for these tests (with identical content). It should help to make the initial intent "merge file with identical content" clearer. I am still using a two steps (backout, then change content) approach to facilitate careful validation of the output change. Doing so has a large impact on the output of the "copy info in changeset extra" variant added in 5e72827dae1e (2 changesets after deeb215be33). It seems to highlight various breakage when merge without content change are involved, this is a good example of why we want to explicitly test theses cases. Because the different -do- matters a lot. Fixing the "copy info in changeset extra" is not a priority here. Because (1) this changeset does not break anything, it only highlight that they were always broken. (2) the only people using "copy info in changeset extra" do not have merge. Differential Revision: https://phab.mercurial-scm.org/D9587

upgrade: speed up when we have only nodemap to downgrade Similar to what we do on upgrade, if we have only persistent-nodemap to downgrade we will just delete the nodemap files and update repository requirements instead of processing all the revlogs. After downgrade, we are left with unrequired docket and transaction files which seems fine but can work on deleting them if someone feels we should. Differential Revision: https://phab.mercurial-scm.org/D9992

upgrade: write nodemap for manifests too In 98e39f04d60e I assumed that writing nodemap for manifests was not desirable and stopped writing it during upgrade. However in recent discussion with Pierre-Yves, I learnt that that's not true. Differential Revision: https://phab.mercurial-scm.org/D9991

windows: fix parsing of version number to match format from D9955 Differential Revision: https://phab.mercurial-scm.org/D10061