From 2b281d5ec758d3bddbf27c4098f0767e2471227a Mon Sep 17 00:00:00 2001
From: Karen Arutyunov <karen@codesynthesis.com>
Date: Fri, 3 Apr 2020 17:36:45 +0300
Subject: Skip unmatched lines in $regex.replace_lines() if format_no_copy flag
 is specified

---
 libbuild2/functions-regex.cxx   |  8 +++++---
 tests/function/regex/testscript | 20 ++++++++++++++++++++
 2 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/libbuild2/functions-regex.cxx b/libbuild2/functions-regex.cxx
index 6a8c83a..10067a4 100644
--- a/libbuild2/functions-regex.cxx
+++ b/libbuild2/functions-regex.cxx
@@ -275,6 +275,7 @@ namespace build2
       is.exceptions (istringstream::badbit);
 
       const string& efmt (fmt ? *fmt : "");
+      bool no_copy ((fl.second & regex_constants::format_no_copy) != 0);
 
       for (string l; !eof (getline (is, l)); )
       {
@@ -282,9 +283,10 @@ namespace build2
         string& s (rr.first);
 
         // Skip the empty replacement for a matched line if the format is
-        // absent.
+        // absent and an unmatched line if the format_no_copy flag is
+        // specified.
         //
-        if (!fmt && rr.second && s.empty ())
+        if (rr.second ? !fmt && s.empty () : no_copy)
           continue;
 
         if (!rls)
@@ -553,7 +555,7 @@ namespace build2
     //
     // return_lines - return the simple name (rather than a name list)
     //                containing the unmatched lines and line replacements
-    //                seperated with newlines.
+    //                separated with newlines.
     //
     // Note that if format_no_copy is specified, unmatched lines are not
     // copied either.
diff --git a/tests/function/regex/testscript b/tests/function/regex/testscript
index fc7fb92..95dfbb8 100644
--- a/tests/function/regex/testscript
+++ b/tests/function/regex/testscript
@@ -146,6 +146,15 @@
         print $regex.replace_lines($v, '(.*)\.cxx', '\1.hxx')
         EOI
 
+      : no-copy
+      :
+      $* <<EOI >'foo.hxx'
+        v = "foo.cxx
+        bar.txt"
+
+        print $regex.replace_lines($v, '(.*)\.cxx', '\1.hxx', format_no_copy)
+        EOI
+
       : null-fmt
       :
       $* <<EOI >'bar.txt'
@@ -173,6 +182,17 @@
         bar.txt
         EOO
 
+      : no-copy
+      :
+      $* <<EOI >'bar.hxx'
+        v = "foo.cxx
+        bar.txt"
+
+        print $regex.replace_lines($v, \
+                                   '(.*)\.txt', '\1.hxx', \
+                                   format_no_copy return_lines)
+        EOI
+
       : null-fmt
       :
       $* <<EOI >'bar.txt'
-- 
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