[LyX/2.1.x] Don't update paths of non-existing files

[Enrico Forestieri]

commit 8a015fce2fb07fd91e9e7c01d258c0f3574f83e8
Author: Enrico Forestieri <for...@lyx.org>
Date:   Tue May 5 22:47:46 2015 +0200

    Don't update paths of non-existing files
    
    No status line needed as this is an amendment to [4543bf28/lyxgit].

diff --git a/src/Buffer.cpp b/src/Buffer.cpp
index 52212e8..782cbad 100644
--- a/src/Buffer.cpp
+++ b/src/Buffer.cpp
@@ -4950,17 +4950,21 @@ void Buffer::checkMasterBuffer()
 }
 
 
-string Buffer::includedFilePath(string const & name) const
+string Buffer::includedFilePath(string const & name, string const & ext) const
 {
-       if (d->old_position.empty() || d->old_position == filePath())
+       bool isabsolute = FileName::isAbsolute(name);
+       // old_position already contains a trailing path separator
+       string const absname = isabsolute ? name : d->old_position + name;
+
+       if (d->old_position.empty() || d->old_position == filePath()
+           || !FileName(addExtension(absname, ext)).exists())
                return name;
 
-       if (FileName::isAbsolute(name))
+       if (isabsolute)
                return to_utf8(makeRelPath(from_utf8(name), 
from_utf8(filePath())));
 
-       // old_position already contains a trailing path separator
-       string const cleanpath = FileName(d->old_position + name).realPath();
-       return to_utf8(makeRelPath(from_utf8(cleanpath), 
from_utf8(filePath())));
+       return to_utf8(makeRelPath(from_utf8(FileName(absname).realPath()),
+                                  from_utf8(filePath())));
 }
 
 } // namespace lyx
diff --git a/src/Buffer.h b/src/Buffer.h
index e855c20..1c6e808 100644
--- a/src/Buffer.h
+++ b/src/Buffer.h
@@ -707,11 +707,14 @@ public:
        ///
        void checkMasterBuffer();
 
-       /// If the document is being saved to a new location, return the
-       /// updated path of an included file relative to the new buffer path
-       /// if possible, otherwise return its absolute path.
+       /// If the document is being saved to a new location and the named file
+       /// exists at the old location, return its updated path relative to the
+       /// new buffer path if possible, otherwise return its absolute path.
        /// In all other cases, this is a no-op and name is returned unchanged.
-       std::string includedFilePath(std::string const & name) const;
+       /// If a non-empty ext is given, the existence of name.ext is checked
+       /// but the returned path will not contain this extension.
+       std::string includedFilePath(std::string const & name,
+                               std::string const & ext = empty_string()) const;
 
        /// compute statistics between \p from and \p to
        /// \p from initial position
diff --git a/src/insets/InsetCommandParams.cpp 
b/src/insets/InsetCommandParams.cpp
index 519e937..074bd3a 100644
--- a/src/insets/InsetCommandParams.cpp
+++ b/src/insets/InsetCommandParams.cpp
@@ -346,7 +346,7 @@ void InsetCommandParams::Write(ostream & os, Buffer const * 
buffer) const
                                string newdata;
                                string bib = token(data, ',', i);
                                while (!bib.empty()) {
-                                       bib = buffer->includedFilePath(bib);
+                                       bib = buffer->includedFilePath(bib, 
"bib");
                                        if (!newdata.empty())
                                                newdata.append(1, ',');
                                        newdata.append(bib);