commit-graph: Add a way to write commit-graph files

[lhchavez]

This change adds the git_commit_graph_writer_* functions to allow to
write and create commit-graph files from .idx/.pack files or
git_revwalks.

Part of: #5757

[ethomson]

Thanks again for your work on commit graphs, this is really exciting stuff. A few minor nits and a few questions. One additional question - are you using some tool to format your code? Your formatting seems consistent with itself but not particularly consistent with the rest of the project. Curious if this is your style, a tool, etc...

[lhchavez]

Thanks again for your work on commit graphs, this is really exciting stuff. A few minor nits and a few questions. One additional question - are you using some tool to format your code? Your formatting seems consistent with itself but not particularly consistent with the rest of the project. Curious if this is your style, a tool, etc...

yes! i am using clang-format with settings that tried to be as consistent as possible with the rest of the codebase (but apparently didn't meet the goal u_u).

[lhchavez]

Thanks again for your work on commit graphs, this is really exciting stuff. A few minor nits and a few questions. One additional question - are you using some tool to format your code? Your formatting seems consistent with itself but not particularly consistent with the rest of the project. Curious if this is your style, a tool, etc...

yes! i am using clang-format with settings that tried to be as consistent as possible with the rest of the codebase (but apparently didn't meet the goal u_u).

these are the current settings i have:

# .clang-format
---
AlignAfterOpenBracket: AlwaysBreak
AlignConsecutiveAssignments: false
AlignTrailingComments: true
AlignOperands: false
AllowAllParametersOfDeclarationOnNextLine: false
AllowShortBlocksOnASingleLine: false
AllowShortFunctionsOnASingleLine: false
AllowShortIfStatementsOnASingleLine: false
BasedOnStyle: WebKit
BinPackArguments: false
BinPackParameters: false
BreakBeforeBraces: Linux
ColumnLimit: 100
ContinuationIndentWidth: 16
Cpp11BracedListStyle: true
ForEachMacros:
- git_vector_foreach
- git_vector_rforeach
- git_array_foreach
IncludeCategories:
- Priority: 1
  Regex: ^<
- Priority: 2
  Regex: ^[<"]git2/
- Priority: 3
  Regex: ^"
IndentCaseLabels: false
IndentWidth: 8
MaxEmptyLinesToKeep: 2
PointerAlignment: Right
SortIncludes: false
SpacesBeforeTrailingComments: 2
TypenameMacros:
- GIT_EXTERN
UseTab: Always
PenaltyBreakAssignment: 1000
...

[ethomson]

Sorry it's taken so long to get back to this, #5974 took a lot more time than I expected. 😢

One question about the struct initializer. Otherwise, I'm going to take a whack at tweaking clang-format to see if we can get it a little closer to our style.

Then I'm looking forward to merging this and cutting 1.2.0 with all your improvements. Thanks for all the hard work - and your patience in getting them reviewed.

[ethomson]

Sorry about pulling the rug out from under you with the array changes. Thanks for the iteration. 👍

[ethomson]

Sorry about pulling the rug out from under you with the array changes. Thanks for the iteration. 👍

[ethomson]

I did a few formatting fixes because I had it beaten into my head that we should have binary operators at the end of a line not the beginning. I apologize for this compulsion, but there it is.

Manually merged. Thanks for all this work!