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Fix parser advancement in header functions
After parsing a valid header, the current line of the parser should be
the last line of the header. If the header is invalid (the parse
function returns an error), the state of the parser is undefined.
Also add a test since this is easy to mess up.
+70
-9
+16
-9
gitdiff/file_header.go
+16
-9
gitdiff/file_header.go
···
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f := &File{}
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for {
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+
end, err := parseGitHeaderData(f, p.Line(1), defaultName)
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+
if err != nil {
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return nil, p.Errorf(1, "git file header: %v", err)
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+
}
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if end {
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break
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}
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+
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if err := p.Next(); err != nil {
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if err == io.EOF {
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break
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}
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return nil, err
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}
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-
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end, err := parseGitHeaderData(f, p.Line(0), defaultName)
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-
if err != nil {
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return nil, p.Errorf(1, "git file header: %v", err)
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-
}
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-
if end {
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break
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-
}
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}
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if f.OldName == "" && f.NewName == "" {
···
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return nil, nil
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}
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+
// advance past the first line so parser is at end of header
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// no EOF check needed because we know there are >=3 valid lines
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if err := p.Next(); err != nil {
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return nil, err
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}
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+
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oldName, _, err := parseName(oldLine[len(oldPrefix):], '\t', 0)
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if err != nil {
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return nil, p.Errorf(0, "file header: %v", err)
···
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f.NewName = newName
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}
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}
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+
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return f, nil
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}
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···
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// It returns true when header parsing is complete; in that case, line was the
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// first line of non-header content.
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func parseGitHeaderData(f *File, line, defaultName string) (end bool, err error) {
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-
if line[len(line)-1] == '\n' {
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if len(line) > 0 && line[len(line)-1] == '\n' {
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line = line[:len(line)-1]
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}
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+54
gitdiff/file_header_test.go
+54
gitdiff/file_header_test.go
···
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}
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}
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+
func TestParserAdvancment(t *testing.T) {
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tests := map[string]struct {
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Input string
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Parse func(p *parser) error
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+
NextLine string
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}{
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"ParseGitFileHeader": {
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Input: `diff --git a/dir/file.txt b/dir/file.txt
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index 9540595..30e6333 100644
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--- a/dir/file.txt
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+++ b/dir/file.txt
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@@ -1,2 +1,3 @@
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context line
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`,
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Parse: func(p *parser) error {
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_, err := p.ParseGitFileHeader()
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return err
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},
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NextLine: "@@ -1,2 +1,3 @@\n",
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},
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"ParseTraditionalFileHeader": {
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Input: `--- dir/file.txt
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+++ dir/file.txt
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@@ -1,2 +1,3 @@
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context line
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`,
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Parse: func(p *parser) error {
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_, err := p.ParseTraditionalFileHeader()
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return err
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},
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NextLine: "@@ -1,2 +1,3 @@\n",
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},
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}
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for name, test := range tests {
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t.Run(name, func(t *testing.T) {
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p := &parser{r: bufio.NewReader(strings.NewReader(test.Input))}
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p.Next()
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if err := test.Parse(p); err != nil {
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t.Fatalf("unexpected error while parsing: %v", err)
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}
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+
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if err := p.Next(); err != nil {
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t.Fatalf("advancing the parser after parsing returned an error: %v", err)
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}
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+
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if test.NextLine != p.Line(0) {
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t.Errorf("incorrect next line after parsing\nexpected: %q\nactual: %q", test.NextLine, p.Line(0))
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}
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})
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+
}
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+
}
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+
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func TestCleanName(t *testing.T) {
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tests := map[string]struct {
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Input string