[LyX/master] Export/view a PDF even if error

[Scott Kostyshak]

commit cd8be655f1895957fb169cdf361297d9ecc40ec9
Author: Scott Kostyshak <skost...@lyx.org>
Date:   Wed Mar 18 16:51:12 2015 -0400

    Export/view a PDF even if error
    
    A PDF is often still produced after a LaTeX error.
    
    If there was an error when exporting a PDF, we now give an error
    and the PDF (if it exists), where before we gave the error and
    not the PDF. The GUI and command line behaviors are consistent:
    in the GUI an error is given and the PDF is viewed; on the
    command line, a non-zero exit code is given and a PDF is created.
    
    This also solves what was in my mind an inconsistency: if the user
    "updated" a document and there was an error, the resulting
    PDF would be shown; but if the user viewed a document and there
    was an error, the document would not be shown.
    
    Note that this applies to all output formats, not just PDF.
    
    For discussion, see:
    https://www.mail-archive.com/lyx-devel@lists.lyx.org/msg186454.html

diff --git a/src/Buffer.cpp b/src/Buffer.cpp
index f9da416..e045e01 100644
--- a/src/Buffer.cpp
+++ b/src/Buffer.cpp
@@ -4119,12 +4119,10 @@ Buffer::ExportStatus Buffer::doExport(string const & 
target, bool put_in_tempdir
                d->cloned_buffer_->d->errorLists[error_type] = 
d->errorLists[error_type];
        }
 
-       if (!success)
-               return ExportConverterError;
 
        if (put_in_tempdir) {
                result_file = tmp_result_file.absFileName();
-               return ExportSuccess;
+               return success ? ExportSuccess : ExportConverterError;
        }
 
        if (dest_filename.empty())
@@ -4189,7 +4187,7 @@ Buffer::ExportStatus Buffer::doExport(string const & 
target, bool put_in_tempdir
                        formats.prettyName(format)));
        }
 
-       return ExportSuccess;
+       return success ? ExportSuccess : ExportConverterError;
 }
 
 
@@ -4214,11 +4212,10 @@ Buffer::ExportStatus Buffer::preview(string const & 
format, bool includeall) con
        }
        // (2) export with included children only
        ExportStatus const status = doExport(format, true, false, result_file);
-       if (status != ExportSuccess)
-               return status;
-       if (!formats.view(*this, FileName(result_file), format))
+       FileName const previewFile(result_file);
+       if (previewFile.exists() && !formats.view(*this, previewFile, format))
                return PreviewError;
-       return PreviewSuccess;
+       return (status == ExportSuccess) ? PreviewSuccess : status;
 }
 
 
diff --git a/src/LaTeX.cpp b/src/LaTeX.cpp
index e4f8b4b..ed59181 100644
--- a/src/LaTeX.cpp
+++ b/src/LaTeX.cpp
@@ -110,6 +110,10 @@ LaTeX::LaTeX(string const & latex, OutputParams const & rp,
 
 void LaTeX::deleteFilesOnError() const
 {
+       // Note that we do not always call this function when there is an error.
+       // For example, if there is an error but an output file is produced we
+       // still would like to output (export/view) the file.
+
        // What files do we have to delete?
 
        // This will at least make latex do all the runs
@@ -236,7 +240,9 @@ int LaTeX::run(TeXErrors & terr)
        }
 
        if (scanres & ERRORS) {
-               deleteFilesOnError();
+               // We no longer run deleteFilesOnError() here
+               // because we now show a resulting PDF even if
+               // there was an error.
                return scanres; // return on error
        }