[LyX/master] Do not break on undefined references that are part of the family.

[Juergen Spitzmueller]

commit 02d2e4aa3279b872c9786718dab4f95fd44e900a
Author: Juergen Spitzmueller <spitz at lyx.org>
Date:   Sat Mar 14 09:43:57 2020 +0100

    Do not break on undefined references that are part of the family.
    
    Thus a document can be viewed if it contains references to
    its master, children or siblings that are being excluded via includeonly,
    or viewed standalone if it contains references to its master or siblings.
---
 src/Converter.cpp |    4 ++--
 src/LaTeX.cpp     |   23 +++++++++++++++++++----
 src/LaTeX.h       |    2 ++
 3 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/src/Converter.cpp b/src/Converter.cpp
index 77aef9e..cb98b44 100644
--- a/src/Converter.cpp
+++ b/src/Converter.cpp
@@ -875,7 +875,7 @@ Converters::RetVal Converters::runLaTeX(Buffer const & buffer, string const & co
 	if (result & LaTeX::ERRORS)
 		buffer.bufferErrors(terr, errorList);
 
-	if ((result & LaTeX::UNDEF_CIT) || (result & LaTeX::UNDEF_REF)) {
+	if ((result & LaTeX::UNDEF_CIT) || (result & LaTeX::UNDEF_UNKNOWN_REF)) {
 		buffer.bufferRefs(terr, errorList);
 		if (errorList.empty())
 			errorList.push_back(ErrorItem(_("Undefined reference"),
@@ -913,7 +913,7 @@ Converters::RetVal Converters::runLaTeX(Buffer const & buffer, string const & co
 			LaTeX::NO_LOGFILE |
 			LaTeX::ERRORS |
 			LaTeX::UNDEF_CIT |
-			LaTeX::UNDEF_REF |
+			LaTeX::UNDEF_UNKNOWN_REF |
 			LaTeX::NO_OUTPUT;
 
 	return (result & ERROR_MASK) == 0 ? SUCCESS : FAILURE;
diff --git a/src/LaTeX.cpp b/src/LaTeX.cpp
index a7b3903..0401e64 100644
--- a/src/LaTeX.cpp
+++ b/src/LaTeX.cpp
@@ -795,6 +795,7 @@ int LaTeX::scanLogFile(TeXErrors & terr)
 	bool fle_style = false;
 	static regex const file_line_error(".+\\.\\D+:[0-9]+: (.+)");
 	static regex const child_file("[^0-9]*([0-9]+[A-Za-z]*_.+\\.tex).*");
+	static regex const undef_ref(".*Reference `(\\w+)\\' on page.*");
 	// Flag for 'File ended while scanning' message.
 	// We need to wait for subsequent processing.
 	string wait_for_error;
@@ -895,15 +896,29 @@ int LaTeX::scanLogFile(TeXErrors & terr)
 			} else if (contains(token, "Reference")
 				   //&& contains(token, "on input line")) //often split to new line
 				   && contains(token, "undefined")) {
+				if (regex_match(token, sub, undef_ref)) {
+					string const ref = sub.str(1);
+					Buffer const * buf = theBufferList().getBufferFromTmp(file.absFileName());
+					if (!buf || !buf->masterBuffer()->activeLabel(from_utf8(ref))) {
+						terr.insertRef(getLineNumber(token), from_ascii("Reference undefined"),
+							from_utf8(token), child_name);
+						retval |= UNDEF_UNKNOWN_REF;
+					}
+				}
 				retval |= UNDEF_REF;
-				terr.insertRef(getLineNumber(token), from_ascii("Reference undefined"),
-					from_utf8(token), child_name);
 
 			//If label is too long pdlaftex log line splitting will make the above fail
 			//so we catch at least this generic statement occuring for both CIT & REF.
 			} else if (!runparams.includeall && contains(token, "There were undefined references.")) {
-				if (!(retval & UNDEF_CIT)) //if not handled already
-					 retval |= UNDEF_REF;
+				if (!(retval & UNDEF_CIT)) { //if not handled already
+					if (regex_match(token, sub, undef_ref)) {
+						string const ref = sub.str(1);
+						Buffer const * buf = theBufferList().getBufferFromTmp(file.absFileName());
+						if (!buf || !buf->masterBuffer()->activeLabel(from_utf8(ref)))
+							retval |= UNDEF_UNKNOWN_REF;
+					}
+					retval |= UNDEF_REF;
+				}
 			}
 
 		} else if (prefixIs(token, "Package")) {
diff --git a/src/LaTeX.h b/src/LaTeX.h
index 4899cd6..b76ec1f 100644
--- a/src/LaTeX.h
+++ b/src/LaTeX.h
@@ -155,6 +155,8 @@ public:
 		///
 		INDEX_ERROR = 65536,
 		///
+		UNDEF_UNKNOWN_REF = 131072,
+		///
 		ERRORS = TEX_ERROR + LATEX_ERROR + NONZERO_ERROR + BIBTEX_ERROR + INDEX_ERROR,
 		///
 		WARNINGS = TEX_WARNING + LATEX_WARNING + PACKAGE_WARNING