mirror of https://github.com/go-gitea/gitea.git
Improve TestPatch to use git read-tree -m and implement git-merge-one-file functionality (#18004)
The current TestPatch conflict code uses a plain git apply which does not properly account for 3-way merging. However, we can improve things using `git read-tree -m` to do a three-way merge then follow the algorithm used in merge-one-file. We can also use `--patience` and/or `--histogram` to generate a nicer diff for applying patches too. Fix #13679 Fix #6417 Signed-off-by: Andrew Thornton <art27@cantab.net>pull/17743/head^2
zeripath
3 years ago
committed by
GitHub
parent
487ce3b49e
commit
f1e85622da
@ -0,0 +1,180 @@
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// Copyright 2021 The Gitea Authors.
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// All rights reserved.
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// Use of this source code is governed by a MIT-style
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// license that can be found in the LICENSE file.
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package pull
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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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"os"
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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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// lsFileLine is a Quadruplet struct (+error) representing a partially parsed line from ls-files
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type lsFileLine struct {
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mode string
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sha string
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stage int
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path string
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err error
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}
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// SameAs checks if two lsFileLines are referring to the same path, sha and mode (ignoring stage)
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func (line *lsFileLine) SameAs(other *lsFileLine) bool {
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if line == nil || other == nil {
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return false
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}
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if line.err != nil || other.err != nil {
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return false
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}
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return line.mode == other.mode &&
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line.sha == other.sha &&
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line.path == other.path
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}
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// readUnmergedLsFileLines calls git ls-files -u -z and parses the lines into mode-sha-stage-path quadruplets
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// it will push these to the provided channel closing it at the end
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func readUnmergedLsFileLines(ctx context.Context, tmpBasePath string, outputChan chan *lsFileLine) {
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defer func() {
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// Always close the outputChan at the end of this function
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close(outputChan)
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}()
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lsFilesReader, lsFilesWriter, err := os.Pipe()
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if err != nil {
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log.Error("Unable to open stderr pipe: %v", err)
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outputChan <- &lsFileLine{err: fmt.Errorf("unable to open stderr pipe: %v", err)}
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return
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}
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defer func() {
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_ = lsFilesWriter.Close()
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_ = lsFilesReader.Close()
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}()
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stderr := &strings.Builder{}
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err = git.NewCommandContext(ctx, "ls-files", "-u", "-z").
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RunInDirTimeoutEnvFullPipelineFunc(
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nil, -1, tmpBasePath,
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lsFilesWriter, stderr, nil,
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func(_ context.Context, _ context.CancelFunc) error {
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_ = lsFilesWriter.Close()
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defer func() {
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_ = lsFilesReader.Close()
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}()
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bufferedReader := bufio.NewReader(lsFilesReader)
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for {
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line, err := bufferedReader.ReadString('\000')
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if err != nil {
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if err == io.EOF {
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return nil
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}
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return err
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}
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toemit := &lsFileLine{}
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split := strings.SplitN(line, " ", 3)
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if len(split) < 3 {
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return fmt.Errorf("malformed line: %s", line)
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}
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toemit.mode = split[0]
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toemit.sha = split[1]
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if len(split[2]) < 4 {
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return fmt.Errorf("malformed line: %s", line)
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}
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toemit.stage, err = strconv.Atoi(split[2][0:1])
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if err != nil {
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return fmt.Errorf("malformed line: %s", line)
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}
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toemit.path = split[2][2 : len(split[2])-1]
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outputChan <- toemit
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}
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})
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if err != nil {
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outputChan <- &lsFileLine{err: fmt.Errorf("git ls-files -u -z: %v", git.ConcatenateError(err, stderr.String()))}
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}
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}
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// unmergedFile is triple (+error) of lsFileLines split into stages 1,2 & 3.
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type unmergedFile struct {
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stage1 *lsFileLine
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stage2 *lsFileLine
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stage3 *lsFileLine
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err error
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}
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// unmergedFiles will collate the output from readUnstagedLsFileLines in to file triplets and send them
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// to the provided channel, closing at the end.
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func unmergedFiles(ctx context.Context, tmpBasePath string, unmerged chan *unmergedFile) {
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defer func() {
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// Always close the channel
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close(unmerged)
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}()
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ctx, cancel := context.WithCancel(ctx)
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lsFileLineChan := make(chan *lsFileLine, 10) // give lsFileLineChan a buffer
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go readUnmergedLsFileLines(ctx, tmpBasePath, lsFileLineChan)
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defer func() {
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cancel()
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for range lsFileLineChan {
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// empty channel
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}
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}()
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next := &unmergedFile{}
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for line := range lsFileLineChan {
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if line.err != nil {
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log.Error("Unable to run ls-files -u -z! Error: %v", line.err)
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unmerged <- &unmergedFile{err: fmt.Errorf("unable to run ls-files -u -z! Error: %v", line.err)}
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return
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}
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// stages are always emitted 1,2,3 but sometimes 1, 2 or 3 are dropped
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switch line.stage {
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case 0:
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// Should not happen as this represents successfully merged file - we will tolerate and ignore though
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case 1:
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if next.stage1 != nil {
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// We need to handle the unstaged file stage1,stage2,stage3
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unmerged <- next
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}
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next = &unmergedFile{stage1: line}
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case 2:
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if next.stage3 != nil || next.stage2 != nil || (next.stage1 != nil && next.stage1.path != line.path) {
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// We need to handle the unstaged file stage1,stage2,stage3
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unmerged <- next
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next = &unmergedFile{}
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}
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next.stage2 = line
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case 3:
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if next.stage3 != nil || (next.stage1 != nil && next.stage1.path != line.path) || (next.stage2 != nil && next.stage2.path != line.path) {
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// We need to handle the unstaged file stage1,stage2,stage3
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unmerged <- next
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next = &unmergedFile{}
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}
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next.stage3 = line
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default:
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log.Error("Unexpected stage %d for path %s in run ls-files -u -z!", line.stage, line.path)
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unmerged <- &unmergedFile{err: fmt.Errorf("unexpected stage %d for path %s in git ls-files -u -z", line.stage, line.path)}
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return
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}
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}
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// We need to handle the unstaged file stage1,stage2,stage3
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if next.stage1 != nil || next.stage2 != nil || next.stage3 != nil {
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unmerged <- next
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}
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}
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