backwards compatibility issue in the last month or so

[nrc]

Some time between 2019-06-14 and 2019-07-19, the default formatting changed, this breaks rustfmt's backwards compatibility guarantee.

I see two kinds of changes:

-            ConfChangeType::BeginMembershipChange | ConfChangeType::FinalizeMembershipChange => {
-                unimplemented!()
-            }
+            ConfChangeType::BeginMembershipChange | ConfChangeType::FinalizeMembershipChange => unimplemented!(),

and

-                Datum::Bytes(
-                    "НОЧЬ НА ОКРАИНЕ МОСКВЫ"
-                        .as_bytes()
-                        .to_vec(),
-                ),
+                Datum::Bytes("НОЧЬ НА ОКРАИНЕ МОСКВЫ".as_bytes().to_vec()),
+                Datum::Bytes("НОЧЬ НА ОКРАИНЕ МОСКВЫ".as_bytes().to_vec()),

The second seems to require >1 byte characters.

There are many more instances in https://github.com/tikv/tikv/pull/5137/files

Thanks!

[scampi]

Below is the list of commits for the range reported by @nrc. Few are mine and probably the second change (about unicode) is probably mine where I didn't gated the changes. I will have a look at this one.

• c0e616b Implement closing-block procedure without relying on missed_span module (Implement closing-block procedure without relying on missed_span module #3691)
• 76e2ba2 Skip Attribute #3665: Implemented (#3665: Implemented #3689)
• 66c27c9 Add #[ignore] to test that runs external process (Add #[ignore] to test that runs external process #3690)
• 640b8d0 Update CHANGELOG.md
• 65931cd Release 1.3.3
• e8b2ae1 Update CHANGELOG.md
• 89940e5 Fix bugs related to file-lines (Fix bugs related to file-lines #3684)
• 6487422 fix print-config minimal option (fix print-config minimal option #3687)
• 0e6896b Merge pull request Add --manifest-path support to cargo fmt #3683 from calebcartwright/accept-manifest-path
• 6f67f07 refactor: simplify manifest_path option checks
• aef8e93 Merge remote-tracking branch 'upstream/master' into accept-manifest-path
• 71289e1 fix 'extra comma inserted due to comment' (fix 'extra comma inserted due to comment' #3677)
• e55fc6b Fix using --help, --verbose, etc. (Fix using --help, --verbose, etc. #3620)
• 37695b3 Extract configuration snippet tests into own module (Extract configuration snippet tests into own module #3667)
• 17cbbd8 feat: add --manifest-path support to cargo fmt
• 679c8d5 Release 1.3.2
• c1c532c Update CHANGELOG.md
• 3200af9 Do not consider macro-origin await as chain item (Do not consider macro-origin await as chain item #3671)
• ff49b80 fix: handling of --all when dep name and dir name differ (fix: handling of --all when local dep name and dir name differ #3664)
• 44149d6 Release 1.3.1
• 8c29e8b Update rustfmt-config_proc_macro to 0.1.2
• a8ca806 Update rustfmt-config_proc_macro to 0.1.1
• 1f06a8b fix extraction of missing comments when rewriting an empty where clause (fix extraction of missing comments when rewriting an empty where clause #3663)
• b6f7f24 Merge pull request fix handling on associated type bounds #3661 from calebcartwright/associated-type-bounds
• d9e42ae tests: add tests for assoscaited_type_bounds fix
• 1ee51a4 Add support for windows-style paths in ignore patterns (Add support for windows-style paths in ignore patterns #3633)
• 731f7d5 fix: handling of associated type bounds
• e0e2f0d Don't panic on license check errors (Don't panic on license check errors #3655)
• c955b59 fix: run in sub dirs/workspace member dirs (fix: support running in sub directories/workspace member directories #3652)
• 9986b9d fix internal error for long closure types (fix internal error for long closure types #3653)
• 5616533 Add newline after help text (Add newline after help text #3650)
• 26d370e remove unreachable!() (remove unreachable!() #3646)
• 5b0ce0e avoid not to truncate necessary chars (avoid not to truncate necessary chars #3640)
• 1d19a08 Format the last expression-statement as expression (Format the last expression-statement as expression #3631)
• 84c2356 handle unicode chars in closures (handle unicode chars in closures #3632)
• 944fc57 tests: ensure min number of system/idempotent tests ran (Add checks to ensure system and idempotence tests were executed #3629)
• aa0c9dd tests: add normalize_doc_attributes config tests (add normalize_doc_attributes config tests #3630)
• 4b102fd Merge pull request Fix is_subpath #3628 from topecongiro/issue-3627
• a4eab17 Fix is_subpath

[nrc]

Thanks @scampi ! Fwiw, I think the breaking change for unicode might be acceptable? If it's a one-off and it is communicated. It is clearly a big fix and shouldn't affect too many users. OTOH, having an opt-in also seems good.