Improve reporting of undefined control sequences in preamble

Fixes #11844

diff --git a/src/LaTeX.cpp b/src/LaTeX.cpp
index 5333c7fbae84a0dd81348a9f787533a0f1aca853..be9465495417c17b22e5904a0d0ad5e1b7af897c 100644 (file)
--- a/src/LaTeX.cpp
+++ b/src/LaTeX.cpp
@@ -1051,10 +1051,15 @@ int LaTeX::scanLogFile(TeXErrors & terr)
 
                        // get the next line
                        int count = 0;
+                       // We also collect intermediate lines
+                       // This is needed for errors in preamble
+                       string intermediate;
                        do {
                                if (!getline(ifs, tmp))
                                        break;
                                tmp = rtrim(tmp, "\r");
+                               if (!prefixIs(tmp, "l."))
+                                       intermediate += tmp;
                                // 15 is somewhat arbitrarily chosen, based on practice.
                                // We used 10 for 14 years and increased it to 15 when we
                                // saw one case.
@@ -1076,6 +1081,15 @@ int LaTeX::scanLogFile(TeXErrors & terr)
                                sscanf(tmp.c_str(), "l.%d", &line);
                                // get the rest of the message:
                                string errstr(tmp, tmp.find(' '));
+                               bool preamble_error = false;
+                               if (suffixIs(errstr, "\\begin{document}")) {
+                                       // this is an error in preamble
+                                       // the real error is in the
+                                       // intermediate lines
+                                       errstr = intermediate;
+                                       tmp = intermediate;
+                                       preamble_error = true;
+                               }
                                errstr += '\n';
                                getline(ifs, tmp);
                                tmp = rtrim(tmp, "\r");
@@ -1088,6 +1102,9 @@ int LaTeX::scanLogFile(TeXErrors & terr)
                                        getline(ifs, tmp);
                                        tmp = rtrim(tmp, "\r");
                                }
+                               if (preamble_error)
+                                       // Add a note that the error is to be found in preamble
+                                       errstr += "\n" + to_utf8(_("(NOTE: The erroneous command is in the preamble)"));
                                LYXERR(Debug::LATEX, "line: " << line << '\n'
                                        << "Desc: " << desc << '\n' << "Text: " << errstr);
                                if (line == last_line)