This only updates to Go 1.21 baseline, which is what the module still
specifies as the minimum version. I'll need to run this again when
moving to Go 1.25 or 1.26 as minimum.
Previously, this returned an io.ErrUnexpectedEOF. This is not wrong, in
that we did unexpectedly hit the end of the input file, but it is vague
and implies a possible library bug rather than a problem with the patch
or the input. This condition is really a conflict, as the changes
described by the patch are not compatible with the state of the input.
Remove the Applier type and replace it with TextApplier and
BinaryApplier, both of which operate on fragments instead of on full
files. Move the logic that previously existed in Applier.ApplyFile to
the top-level Apply function.
Also restructure arguments and methods to make it clear that appliers
are one-time-use objects. The destination is now set when creating an
applier and the Reset() method was replaced by Close().
When applying a text fragment that deletes all content in the file, make
sure there is no content left in the source after using all the lines in
the fragment. If there is is extra content, it's a conflict: something
added more lines to the file after generating the patch.
This function parses patch headers (the preamble returned by the
existing Parse function) to extract information about the commit that
generated the patch. This is useful when patches are an interchange
format and this library is applying commits generated elsewhere.
Because of the variety of header formats, parsing is fairly lenient and
best-effort, although certain invalid input does cause errors.
This also extracts some test utilities from the apply tests for reuse.
This removes the distinction between "strict" and "fuzzy" application
by allowing future methods on Applier that control settings. It also
avoids state tracking in the text fragment apply signature by moving it
into the Applier type.
While in practice, an Applier will be used once and discarded, the
capability is provided to reset it for multiple uses.
This is functionally equivalent to the previous version (except for one
error case), but uses the new interface. I think the code is simpler
overall because it removes the line tracking.
These cover some of the possible errors with delta fragments. Many of
the same tests could be implemented slightly easier by testing the
helper functions, but the infrastructure is already set up to test the
full function.
This is made easier by the bin.go CLI, which can parse and encode binary
patch data. Once parsed, fragments were manipulated with truncate and
dd, encoded, and placed in the patch files.
Covers basic literal and delta application. Input files were created by
using dd and the 'conv=notrunc' option to modify sections of files
created from /dev/urandom. All file start with two null bytes to
convince Git they are binary.
Conflict errors are now represented by an exported type that is
compatible with errors.Is instead of using the method defined on
ApplyError. This makes the tests slightly cleaner and should be more
idiomatic for clients.
Billy Keyes