I recommend you read the NICE RELEASE NOTES first.

These are the auto-generated release notes, which are exhaustive if not pretty.

1.0.0 (2020-02-26)

Bug Fixes

• checkout: don't treat modified files as conflicted unless the file would actually change (#1018) (321618f)
• fetch, push: recognize more git config settings (#1033) (a4e5aee)
• types: tweak onAuth typings + add http.d.ts (#1053) (7b05b3d)
• fetch without a 'ref' param should still work if HEAD points to a non-existing branch (#1055) (429fde1)
• isogit CLI had wrong import path to ./http/node (ec1dce0)
• Merge branch 'master' into beta (#872) (b9e5db4)
• pathological graph traversal in findMergeBase (#1057) (8e53088)
• tweak error types (#1061) (424255b)
• update Web Worker example (32b64ca)
• use .js extension for http/web UMD build (4a6a1c2)

chore

• 'message' events are no longer trimmed, and 'rawmessage' event removed (#1010) (92fd6ea)
• cleanup 'dist' directory (#1012) (a1ae219)
• improve readObject and writeObject typings (#1023) (9f905d9)
• improved errors (#1059) (df3b16b)
• make 'http' param required (#1030) (47abb7a)
• make onAuth the replacement for username, password, token, and oauth2format (#1051) (e344578)
• make newSubmoduleBehavior and noSubmodules the default behavior (#1045) (9cd7f3d)
• no plugin system (#1027) (8aaa232)
• remove 'verify' function (#1047) (59e5b12)
• remove automatic URL mangling and User-Agent setting (#1050) (e7d0842)
• remove date option from author/committer/tagger (#1052) (ccb526c)
• remove deprecated 'fs' and 'emitter' params (#1016) (8bb09e5)
• remove the 'autoTranslateSSH' feature (#1006) (7b04575)
• remove the sign command (#1007) (a549b2b)
• rename fastCheckout to checkout (#1002) (ef595b9)
• replace statusMatrix's pattern param with filter param (#1004) (fe6d98a)
• push: improve schema design of PushResult (#1036) (08ce40e)
• return Uint8Arrays instead of Buffers (#1009) (2c1e26f)
• simplify log command (#1005) (2ae9b78)
• switch to autogenerated TypeScript definitions (#1019) (e2e7d40)

Features

• fetch: Added 'pruneTags' parameter (#840) (#847) (fefdf0a)
• add a default export and support for importing the ES module build in Node 12+ (#1043) (064e624)
• bump supported browser versions (#932) (db611be)
• publish beta release (#848) (71413c7)
• publish beta release (#848) (37fecc6)
• rename walkBeta2 to walk (#1001) (1d9c097)
• onAuth: remove OAuth2 variant, support raw HTTP headers, endless retry, canceling (#1054) (f51e489)

BREAKING CHANGES

• E has been removed and replaced by Errors. The errors are typed so if you use an instanceof comparison in the catch statement, auto-completion on their .data property works. There are fewer errors total, they have shorter names, and thus the resulting gzip bundle is smaller despite the addition of 28 new classes. Lastly, the distinction between Fail and Error has been removed since it was subjective.

Here's the complete breakdown of which Errors classes replaced which E codes:

• AlreadyExistsError replaces AddingRemoteWouldOverwrite, NoteAlreadyExistsError, RefExistsError
• AmbiguousError replaces AmbiguousShortOid
• CheckoutConflictError replaces CheckoutConflictError
• CommitNotFetchedError replaces CommitNotFetchedError
• EmptyServerResponseError replaces EmptyServerResponseFail
• FastForwardError replaces FastForwardFail
• GitPushError replaces GitPushError
• HttpError replaces HTTPError
• InternalError replaces InternalFail
• InvalidFilepathError replaces DirectorySeparatorsError
• InvalidOidError replaces CorruptShallowOidFail, NotAnOidFail
• InvalidRefNameError replaces InvalidRefNameError
• MaxDepthError replaces MaxSearchDepthExceeded
• MergeNotSupportedError replaces MergeNotSupportedFail
• MissingNameError replaces MissingAuthorError, MissingCommitterError, MissingTaggerError
• MissingParameterError replaces MissingRequiredParameterError
• NoRefspecError replaces NoRefspecConfiguredError
• NotFoundError replaces ExpandRefError, FileReadError, GitRootNotFoundError, ReadObjectFail, RefNotExistsError, ResolveRefError, ShortOidNotFound, TreeOrBlobNotFoundError
• ObjectTypeError replaces DirectoryIsAFileError, ObjectTypeAssertionFail, ObjectTypeAssertionInPathFail, ObjectTypeAssertionInTreeFail, ObjectTypeUnknownFail, ResolveCommitError, ResolveTreeError
• ParseError replaces AssertServerResponseFail, UnparseableServerResponseFail
• PushRejectedError replaces PushRejectedNonFastForward, PushRejectedTagExists
• RemoteCapabilityError replaces RemoteDoesNotSupportDeepenNotFail, RemoteDoesNotSupportDeepenRelativeFail, RemoteDoesNotSupportDeepenSinceFail, RemoteDoesNotSupportShallowFail
• SmartHttpError replaces RemoteDoesNotSupportSmartHTTP
• UnknownTransportError replaces UnknownTransportError
• UrlParseError replaces RemoteUrlParseError
• UserCanceledError replaces UserCancelledError

The following error codes are no longer used / have no equivalent: AcquireLockFileFail, BranchDeleteError, CoreNotFound, DoubleReleaseLockFileFail, InvalidDepthParameterError, InvalidParameterCombinationError, MismatchRefValueError, NoHeadCommitError, NotImplementedFail, ObjectTypeAssertionInRefFail, PluginSchemaViolation, PluginUndefined, PluginUnrecognized

• Drop official support for Safari 11
• The author.date, committer.date, tagger.date parameters were removed in favor of author.timestamp, comitter.timestamp, tagger.timestamp in order to be clear about what is actually written and better reflect the return types in readCommit, log, and readTag.
• The username, password, token, and oauth2format params were removed and replaced with the onAuth callback. Since onAuth also replaced the credentialManager plugin, this means now there is a single way to do authentication instead of two.
• The URL that's provided is now the URL that's used; no longer will they be "fixed" to end with .git since sometimes that actually makes things worse, and subverts user expectations. Accordingly, the noGitSuffix parameter has been removed since it's the default behavior. Furthermore, the User-Agent is now totally in the user's hands, because it is just a minefield, and I'm done trying to make sense of it. I added a Headers page to the docs documenting what I know about User-Agent + GitHub + CORS + Chrome bugs.
• The verify function has been removed, and the signature property of TagObject renamed to gpgsig to match CommitObject. Since log, readCommit, and readTag all include the gpgsig and signing payload in their return values now, it is simpler and more efficient to do the verification outside of isomorphic-git. See the documentation for the onSign parameter for complete code examples.
• The newSubmoduleBehavior parameter has been removed and is now the default and only behavior, because it is good. And the noSubmodules parameter has been removed and is also the default and only behavior. (This only affects you if you a) liked seeing the console warnings or b) were using statusMatrix to traverse submodules for some reason.)
• push: the push function now throws if any of the refs on the remote were not updated successfully. It also returns a nicely typed result object organized by ref, rather than a loose collection of strings organized by outcome.
• fetch, push: the fetch and push functions now respect previously ignored git config settings like: branch.${ref}.pushRemote, remote.pushDefault, remote.${remote}.pushurl, and branch.${ref}.merge. (Note the pull command already respected branch.${ref}.merge but fetch did not.)
• isomorphic-git no longer has a node HTTP client hard-coded into the main file and a browser HTTP client hard-coded into the module file. The HTTP clients are now in their own files; users pick one, import it, and provide it to functions that make requests.
• the plugin system has been removed and we're returning to simply passing in arguments and callbacks, because it is simpler, has better locality, and avoids global state.
• readObject and writeObject have been updated to use the same object schemas used in readCommit, readTree, and readTag. And they are actually documented now in the docs. (The main change is trees are simply arrays now, rather than objects with a .entries property.) The types returned by readObject also form a proper discriminated union so TypeScript will infer the type of .object given .format and .type.
• The undocumented param aliases authUsername and authPassword are removed in favor of username and password.
• plugins.set has been replaced by plugins.fs, plugins.emitter, plugins.credentialManager, plugins.pgp, and plugins.http.
• onAuth: The token and oauth2format properties have been removed from the GitAuth interface, which makes it much simpler and and eliminates a dozen GitErrors handling specific edge cases.

A headers property has been added to the GitAuth interface. This makes onAuth much more powerful because you can inject whatever HTTP headers you want.

The onAuthFailed callback now lets you return a GitAuth object. This means you can keep retrying to authenticate as many times as you like.

A cancel property has been added to the GitAuth interface. This means you gracefully give up authenticating and the function will throw an E.UserCancelledError instead of an E.HTTPError.

• The deprecated fs and emitter params have been removed. They've been superseded by the fs and emitter plugins.
• The internal-apis are no longer included in the npm package. I never really intended that; they were just for running unit tests. Also, I renamed dist/for-future/isomorphic-git/index.js to dist/index.js and dist/for-node/isomorphic-git/index.js to dist/index.cjs.

And I removed the jasmine fallback. I'm sorry jest uses native modules, but it's just too good not to use and maintaining a fallback test runner is an added complication.

• As a historical accident, message events were trimmed. This was lossy and removed valuable information, such as an '\r' by itself, which is a signal to update the existing line instead of appending a new one. The rawmessage event was added as a temporary workaround to expose the untrimmed data. The rawmessage event has been removed and from now on, message events emit the full untrimmed data.
• Any functions that returned Buffer objects now instead return Uint8Array objects. This is so we can eventually drop the bloated Buffer browser polyfill.
• Ths sign command was deprecated a while ago (back when commit got a signingKey param) and has now been removed.
• The autoTranslateSSH feature has been removed since it's kind of hacky, and it's trivial to implement your own version using the data.suggestion property of the UnknownTransportError when something fails.
• The signing argument of log has been removed, and log now returns an array of objects with the same interface as those returned from readCommit. Also, the log function will throw now instead of returning errors as objects inside the result array. This greatly simplifies the TS definition (which previously consisted of 3 different overloaded variations) so that we can generate the TS definitions directly from the JSDoc in the future.
• the pattern param added two dependencies to the project (globrex and globalyzer) for very little benefit since we haven't ended up using globbing anywhere else in the library. The same result can be achieved via the new function parameter filter which lets you provide the pattern-matching logic yourself.
• the fastCheckout function has been renamed checkout and the old checkout function has been removed entirely.
• the walkBeta2 function has been renamed walk and the walkBeta1 function has been removed entirely.
• the browser (and node) versions tested in CI have been bumped. Future releases are not guaranteed to work on the older versions anymore.
• Drop official support for Safari 11
• core has been replaced by plugins.createCore and plugins.deleteCore.