vim-patch:8.1.1585: :let-heredoc does not trim enough

Problem:    :let-heredoc does not trim enough.
Solution:   Trim indent from the contents based on the indent of the first
            line.  Use let-heredoc in more tests.
e7eb92708e

runtime/doc/eval.txt

@@ -9793,13 +9793,24 @@ text...
 			If {marker} is not supplied, then "." is used as the
 			default marker.
 
-			Any white space characters in the lines of text are
+			Without "trim" any white space characters in the lines
-			preserved.  If "trim" is specified before {marker},
+			of text are preserved.  If "trim" is specified before
-			then all the leading indentation exactly matching the
+			{marker}, then indentation is stripped so you can do: >
-			leading indentation before `let` is stripped from the
+				let text =<< trim END
-			input lines and the line containing {marker}.  Note
+				   if ok
-			that the difference between space and tab matters
+				     echo 'done'
-			here.
+				   endif
+				END
+<			Results in: ["if ok", "  echo 'done'", "endif"]
+			The marker must line up with "let" and the indentation
+			of the first line is removed from all the text lines.
+			Specifically: all the leading indentation exactly
+			matching the leading indentation of the first
+			non-empty text line is stripped from the input lines.
+			All leading indentation exactly matching the leading
+			indentation before `let` is stripped from the line
+			containing {marker}.  Note that the difference between
+			space and tab matters here.
 
 			If {var-name} didn't exist yet, it is created.
 			Cannot be followed by another command, but can be

src/nvim/eval.c

@@ -1521,7 +1521,9 @@ heredoc_get(exarg_T *eap, char_u *cmd)
 {
   char_u *marker;
   char_u *p;
-  int indent_len = 0;
+  int marker_indent_len = 0;
+  int text_indent_len = 0;
+  char_u *text_indent = NULL;
 
   if (eap->getline == NULL) {
     EMSG(_("E991: cannot use =<< here"));
@@ -1534,14 +1536,16 @@ heredoc_get(exarg_T *eap, char_u *cmd)
       && (cmd[4] == NUL || ascii_iswhite(cmd[4]))) {
     cmd = skipwhite(cmd + 4);
 
-    // Trim the indentation from all the lines in the here document
+    // Trim the indentation from all the lines in the here document.
     // The amount of indentation trimmed is the same as the indentation of
-    // the :let command line.
+    // the first line after the :let command line.  To find the end marker
+    // the indent of the :let command line is trimmed.
     p = *eap->cmdlinep;
     while (ascii_iswhite(*p)) {
       p++;
-      indent_len++;
+      marker_indent_len++;
     }
+    text_indent_len = -1;
   }
 
   // The marker is the next word.  Default marker is "."
@@ -1559,28 +1563,48 @@ heredoc_get(exarg_T *eap, char_u *cmd)
 
   list_T *l = tv_list_alloc(0);
   for (;;) {
-    int i = 0;
+    int mi = 0;
+    int ti = 0;
 
     char_u *theline = eap->getline(NUL, eap->cookie, 0, false);
-    if (theline != NULL && indent_len > 0) {
-      // trim the indent matching the first line
-      if (STRNCMP(theline, *eap->cmdlinep, indent_len) == 0) {
-        i = indent_len;
-      }
-    }
-
     if (theline == NULL) {
       EMSG2(_("E990: Missing end marker '%s'"), marker);
       break;
     }
-    if (STRCMP(marker, theline + i) == 0) {
+
+    // with "trim": skip the indent matching the :let line to find the
+    // marker
+    if (marker_indent_len > 0
+        && STRNCMP(theline, *eap->cmdlinep, marker_indent_len) == 0) {
+        mi = marker_indent_len;
+    }
+    if (STRCMP(marker, theline + mi) == 0) {
       xfree(theline);
       break;
     }
+    if (text_indent_len == -1 && *theline != NUL) {
+        // set the text indent from the first line.
+        p = theline;
+        text_indent_len = 0;
+        while (ascii_iswhite(*p)) {
+            p++;
+            text_indent_len++;
+        }
+        text_indent = vim_strnsave(theline, text_indent_len);
+    }
+    // with "trim": skip the indent matching the first line
+    if (text_indent != NULL) {
+        for (ti = 0; ti < text_indent_len; ti++) {
+            if (theline[ti] != text_indent[ti]) {
+                break;
+            }
+        }
+    }
 
-    tv_list_append_string(l, (char *)(theline + i), -1);
+    tv_list_append_string(l, (char *)(theline + ti), -1);
     xfree(theline);
   }
+  xfree(text_indent);
 
   return l;
 }

src/nvim/testdir/test_cindent.vim

@@ -96,24 +96,24 @@ func Test_cindent_expr()
   call setline(1, testinput)
   call cursor(1, 1)
   call feedkeys("^\<c-v>j$A;\<esc>", 'tnix')
-  let expected =<< trim [CODE]
+  let expected =<< [CODE]
         var_a = something();
-  b = something();
+b = something();
-  [CODE]
+[CODE]
   call assert_equal(expected, getline(1, '$'))
 
   %d
-  let testinput =<< trim [CODE]
+  let testinput =<< [CODE]
                 var_a = something()
                 b = something()
-  [CODE]
+[CODE]
   call setline(1, testinput)
   call cursor(1, 1)
   call feedkeys("^\<c-v>j$A;\<esc>", 'tnix')
-  let expected =<< trim [CODE]
+  let expected =<< [CODE]
         var_a = something();
                 b = something()
-  [CODE]
+[CODE]
   call assert_equal(expected, getline(1, '$'))
   bw!
 endfunc

src/nvim/testdir/test_debugger.vim

@@ -26,27 +26,29 @@ func Test_Debugger()
   endif
 
   " Create a Vim script with some functions
-  call writefile([
+  let lines =<< trim END
-	      \ 'func Foo()',
+	func Foo()
-	      \ '  let var1 = 1',
+	  let var1 = 1
-	      \ '  let var2 = Bar(var1) + 9',
+	  let var2 = Bar(var1) + 9
-	      \ '  return var2',
+	  return var2
-	      \ 'endfunc',
+	endfunc
-	      \ 'func Bar(var)',
+	func Bar(var)
-	      \ '  let var1 = 2 + a:var',
+	  let var1 = 2 + a:var
-	      \ '  let var2 = Bazz(var1) + 4',
+	  let var2 = Bazz(var1) + 4
-	      \ '  return var2',
+	  return var2
-	      \ 'endfunc',
+	endfunc
-	      \ 'func Bazz(var)',
+	func Bazz(var)
-	      \ '  try',
+	  try
-	      \ '    let var1 = 3 + a:var',
+	    let var1 = 3 + a:var
-	      \ '    let var3 = "another var"',
+	    let var3 = "another var"
-	      \ '    let var3 = "value2"',
+	    let var3 = "value2"
-	      \ '  catch',
+	  catch
-	      \ '    let var4 = "exception"',
+	    let var4 = "exception"
-	      \ '  endtry',
+	  endtry
-	      \ '  return var1',
+	  return var1
-	      \ 'endfunc'], 'Xtest.vim')
+	endfunc
+  END
+  call writefile(lines, 'Xtest.vim')
 
   " Start Vim in a terminal
   let buf = RunVimInTerminal('-S Xtest.vim', {})
@@ -294,11 +296,13 @@ func Test_Debugger()
   " Tests for :breakadd file and :breakadd here
   " Breakpoints should be set before sourcing the file
 
-  call writefile([
+  let lines =<< trim END
-	      \ 'let var1 = 10',
+	let var1 = 10
-	      \ 'let var2 = 20',
+	let var2 = 20
-	      \ 'let var3 = 30',
+	let var3 = 30
-	      \ 'let var4 = 40'], 'Xtest.vim')
+	let var4 = 40
+  END
+  call writefile(lines, 'Xtest.vim')
 
   " Start Vim in a terminal
   let buf = RunVimInTerminal('Xtest.vim', {})

src/nvim/testdir/test_let.vim

@@ -199,10 +199,18 @@ END
   END
   call assert_equal(['Line1', '  Line2', "\tLine3", ' END'], var1)
 
+  let var1 =<< trim !!!
+	Line1
+	 line2
+		Line3
+	!!!
+  !!!
+  call assert_equal(['Line1', ' line2', "\tLine3", '!!!',], var1)
+
   let var1 =<< trim
     Line1
   .
-  call assert_equal(['  Line1'], var1)
+  call assert_equal(['Line1'], var1)
 
   " ignore "endfunc"
   let var1 =<< END

src/nvim/testdir/test_popup.vim

@@ -737,11 +737,12 @@ func Test_popup_position()
   if !CanRunVimInTerminal()
     return
   endif
-  call writefile([
+  let lines =<< trim END
-	\ '123456789_123456789_123456789_a',
+    123456789_123456789_123456789_a
-	\ '123456789_123456789_123456789_b',
+    123456789_123456789_123456789_b
-	\ '            123',
+                123
-	\ ], 'Xtest')
+  END
+  call writefile(lines, 'Xtest')
   let buf = RunVimInTerminal('Xtest', {})
   call term_sendkeys(buf, ":vsplit\<CR>")
 

src/nvim/testdir/test_quickfix.vim

@@ -814,7 +814,7 @@ func Test_efm1()
     call writefile(l, 'Xerrorfile1')
     call writefile(l[:-2], 'Xerrorfile2')
 
-    let m =<< trim [DATA]
+    let m =<< [DATA]
 	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx    line  2
 	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx    line  3
 	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx    line  4
@@ -836,7 +836,7 @@ func Test_efm1()
 	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx    line 20
 	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx    line 21
 	xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx    line 22
-    [DATA]
+[DATA]
     call writefile(m, 'Xtestfile')
 
     let save_efm = &efm
@@ -1066,7 +1066,7 @@ func Test_efm2()
     NEW compiler v1.1
     (2,2)   warning: variable 'x' not defined
     (67,3)  warning: 's' already defined
-  -
+    --
   [DATA]
   set efm=%+P[%f]%r,(%l\\,%c)%*[\ ]%t%*[^:]:\ %m,%+Q--%r
   " To exercise the push/pop file functionality in quickfix, the test files