Add go wrapper around git diff-tree --raw -r -M (#33369)
* Implemented calling git diff-tree * Ensures wrapper function is called with valid arguments * Parses output into go struct, using strong typing when possible
This commit is contained in:
Alexander McRae
GitHub
parent
dbc18f400a
commit
a1f1bccd7a
4 changed files with 705 additions and 14 deletions
249
services/gitdiff/git_diff_tree.go
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249
services/gitdiff/git_diff_tree.go
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// Copyright 2025 The Gitea Authors. All rights reserved.
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// SPDX-License-Identifier: MIT
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package gitdiff
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import (
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"bufio"
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"context"
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"fmt"
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"io"
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"strconv"
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"strings"
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"code.gitea.io/gitea/modules/git"
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"code.gitea.io/gitea/modules/log"
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)
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type DiffTree struct {
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Files []*DiffTreeRecord
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}
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type DiffTreeRecord struct {
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// Status is one of 'added', 'deleted', 'modified', 'renamed', 'copied', 'typechanged', 'unmerged', 'unknown'
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Status string
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// For renames and copies, the percentage of similarity between the source and target of the move/rename.
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Score uint8
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HeadPath string
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BasePath string
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HeadMode git.EntryMode
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BaseMode git.EntryMode
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HeadBlobID string
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BaseBlobID string
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}
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// GetDiffTree returns the list of path of the files that have changed between the two commits.
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// If useMergeBase is true, the diff will be calculated using the merge base of the two commits.
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// This is the same behavior as using a three-dot diff in git diff.
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func GetDiffTree(ctx context.Context, gitRepo *git.Repository, useMergeBase bool, baseSha, headSha string) (*DiffTree, error) {
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gitDiffTreeRecords, err := runGitDiffTree(ctx, gitRepo, useMergeBase, baseSha, headSha)
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if err != nil {
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return nil, err
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}
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return &DiffTree{
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Files: gitDiffTreeRecords,
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}, nil
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}
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func runGitDiffTree(ctx context.Context, gitRepo *git.Repository, useMergeBase bool, baseSha, headSha string) ([]*DiffTreeRecord, error) {
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useMergeBase, baseCommitID, headCommitID, err := validateGitDiffTreeArguments(gitRepo, useMergeBase, baseSha, headSha)
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if err != nil {
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return nil, err
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}
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cmd := git.NewCommand(ctx, "diff-tree", "--raw", "-r", "--find-renames", "--root")
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if useMergeBase {
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cmd.AddArguments("--merge-base")
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}
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cmd.AddDynamicArguments(baseCommitID, headCommitID)
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stdout, _, runErr := cmd.RunStdString(&git.RunOpts{Dir: gitRepo.Path})
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if runErr != nil {
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log.Warn("git diff-tree: %v", runErr)
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return nil, runErr
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}
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return parseGitDiffTree(strings.NewReader(stdout))
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}
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func validateGitDiffTreeArguments(gitRepo *git.Repository, useMergeBase bool, baseSha, headSha string) (shouldUseMergeBase bool, resolvedBaseSha, resolvedHeadSha string, err error) {
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// if the head is empty its an error
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if headSha == "" {
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return false, "", "", fmt.Errorf("headSha is empty")
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}
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// if the head commit doesn't exist its and error
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headCommit, err := gitRepo.GetCommit(headSha)
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if err != nil {
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return false, "", "", fmt.Errorf("failed to get commit headSha: %v", err)
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}
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headCommitID := headCommit.ID.String()
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// if the base is empty we should use the parent of the head commit
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if baseSha == "" {
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// if the headCommit has no parent we should use an empty commit
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// this can happen when we are generating a diff against an orphaned commit
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if headCommit.ParentCount() == 0 {
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objectFormat, err := gitRepo.GetObjectFormat()
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if err != nil {
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return false, "", "", err
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}
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// We set use merge base to false because we have no base commit
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return false, objectFormat.EmptyTree().String(), headCommitID, nil
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}
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baseCommit, err := headCommit.Parent(0)
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if err != nil {
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return false, "", "", fmt.Errorf("baseSha is '', attempted to use parent of commit %s, got error: %v", headCommit.ID.String(), err)
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}
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return useMergeBase, baseCommit.ID.String(), headCommitID, nil
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}
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// try and get the base commit
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baseCommit, err := gitRepo.GetCommit(baseSha)
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// propagate the error if we couldn't get the base commit
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if err != nil {
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return useMergeBase, "", "", fmt.Errorf("failed to get base commit %s: %v", baseSha, err)
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}
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return useMergeBase, baseCommit.ID.String(), headCommit.ID.String(), nil
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}
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func parseGitDiffTree(gitOutput io.Reader) ([]*DiffTreeRecord, error) {
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/*
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The output of `git diff-tree --raw -r --find-renames` is of the form:
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:<old_mode> <new_mode> <old_sha> <new_sha> <status>\t<path>
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or for renames:
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:<old_mode> <new_mode> <old_sha> <new_sha> <status>\t<old_path>\t<new_path>
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See: <https://git-scm.com/docs/git-diff-tree#_raw_output_format> for more details
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*/
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results := make([]*DiffTreeRecord, 0)
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lines := bufio.NewScanner(gitOutput)
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for lines.Scan() {
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line := lines.Text()
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if len(line) == 0 {
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continue
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}
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record, err := parseGitDiffTreeLine(line)
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if err != nil {
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return nil, err
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}
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results = append(results, record)
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}
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if err := lines.Err(); err != nil {
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return nil, err
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}
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return results, nil
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}
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func parseGitDiffTreeLine(line string) (*DiffTreeRecord, error) {
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line = strings.TrimPrefix(line, ":")
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splitSections := strings.SplitN(line, "\t", 2)
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if len(splitSections) < 2 {
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return nil, fmt.Errorf("unparsable output for diff-tree --raw: `%s`)", line)
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}
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fields := strings.Fields(splitSections[0])
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if len(fields) < 5 {
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return nil, fmt.Errorf("unparsable output for diff-tree --raw: `%s`, expected 5 space delimited values got %d)", line, len(fields))
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}
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baseMode, err := git.ParseEntryMode(fields[0])
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if err != nil {
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return nil, err
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}
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headMode, err := git.ParseEntryMode(fields[1])
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if err != nil {
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return nil, err
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}
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baseBlobID := fields[2]
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headBlobID := fields[3]
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status, score, err := statusFromLetter(fields[4])
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if err != nil {
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return nil, fmt.Errorf("unparsable output for diff-tree --raw: %s, error: %s", line, err)
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}
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filePaths := strings.Split(splitSections[1], "\t")
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var headPath, basePath string
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if status == "renamed" {
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if len(filePaths) != 2 {
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return nil, fmt.Errorf("unparsable output for diff-tree --raw: `%s`, expected 2 paths found %d", line, len(filePaths))
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}
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basePath = filePaths[0]
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headPath = filePaths[1]
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} else {
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basePath = filePaths[0]
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headPath = filePaths[0]
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}
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return &DiffTreeRecord{
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Status: status,
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Score: score,
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BaseMode: baseMode,
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HeadMode: headMode,
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BaseBlobID: baseBlobID,
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HeadBlobID: headBlobID,
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BasePath: basePath,
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HeadPath: headPath,
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}, nil
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}
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func statusFromLetter(rawStatus string) (status string, score uint8, err error) {
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if len(rawStatus) < 1 {
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return "", 0, fmt.Errorf("empty status letter")
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}
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switch rawStatus[0] {
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case 'A':
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return "added", 0, nil
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case 'D':
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return "deleted", 0, nil
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case 'M':
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return "modified", 0, nil
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case 'R':
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score, err = tryParseStatusScore(rawStatus)
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return "renamed", score, err
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case 'C':
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score, err = tryParseStatusScore(rawStatus)
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return "copied", score, err
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case 'T':
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return "typechanged", 0, nil
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case 'U':
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return "unmerged", 0, nil
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case 'X':
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return "unknown", 0, nil
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default:
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return "", 0, fmt.Errorf("unknown status letter: '%s'", rawStatus)
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}
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}
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func tryParseStatusScore(rawStatus string) (uint8, error) {
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if len(rawStatus) < 2 {
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return 0, fmt.Errorf("status score missing")
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}
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score, err := strconv.ParseUint(rawStatus[1:], 10, 8)
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if err != nil {
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return 0, fmt.Errorf("failed to parse status score: %w", err)
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} else if score > 100 {
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return 0, fmt.Errorf("status score out of range: %d", score)
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}
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return uint8(score), nil
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}
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