fix: emit valid PDF binary marker and omit empty /Contents#344
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oneplus1000 merged 1 commit intoMay 19, 2026
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- gopdf.go: replace mojibake bytes in the PDF binary-comment marker
with the canonical 0xE2 0xE3 0xCF 0xD3 sequence so transfer tools
and viewers reliably detect the file as binary.
- page_obj.go: skip the " /Contents %s\n" line when PageObj.Contents
is empty, preventing a malformed " /Contents \n" entry (seen e.g.
on imported pages that have no content stream).
- Add tests covering both fixes:
- TestPdfBinaryHeader asserts the exact header bytes and that every
marker byte is >= 128 per the PDF spec.
- TestPageObjWriteOmitsContentsWhenEmpty / ...IncludesContentsWhenSet
pin down PageObj.write behavior for both empty and populated
Contents.
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Fix two PDF compliance defects rejected by Adobe Acrobat / Microsoft Edge
Defect 1: Corrupted PDF binary marker comment
gopdf.go:1051writes"%PDF-1.7\n%����\n\n"where����are fourU+FFFD characters embedded in the source code. When Go writes this string
as UTF-8, each U+FFFD becomes the 3-byte sequence EF BF BD, so the output
file contains 12 bytes (
% EF BF BD EF BF BD EF BF BD EF BF BD \n) insteadof the canonical 4-byte binary marker
% E2 E3 CF D3 \nrecommended byISO 32000-1:2008 §7.5.2.
Strict PDF parsers (Adobe Acrobat error 110, Microsoft Edge) sniff these
bytes as malformed UTF-8 and refuse to open the file. Lenient parsers like
PDFium (Chrome) tolerate it, which has hidden the bug.
This was reported in issue #225 (and others).
Fix: write the four canonical bytes via
\xescape sequence:Defect 2: Empty /Contents key in Page objects
page_obj.go:55writes/Contentsunconditionally. When a page has nocontent stream (no native drawing commands — e.g. when only an imported
template is used),
p.Contentsis the empty string, producing the line:This is invalid PDF syntax (a dictionary key with no value). Per
ISO 32000-1:2008 §7.7.3.3,
/Contentsis OPTIONAL — pages without itare spec-legal and render blank.
Fix: emit the
/Contentsline only when there is a value to emit.