vim-patch:8.2.1079: Vim9: no line break allowed in a while loop

Problem:    Vim9: no line break allowed in a while loop.
Solution:   Update stored loop lines when finding line breaks.

https://github.com/vim/vim/commit/d5053d015a957b343ad9c9e45e0abd2978f10cf0

Omit getline_peek(): Vim9 script only.

Co-authored-by: Bram Moolenaar <Bram@vim.org>

4 files changed, 45 insertions, 31 deletions

diff --git a/src/nvim/eval.c b/src/nvim/eval.c
index a79a464860..e5193cdfb8 100644
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -705,8 +705,11 @@ int eval_to_bool(char *arg, bool *error, exarg_T *eap, int skip)
 
   evalarg_T evalarg = {
     .eval_flags = skip ? 0 : EVAL_EVALUATE,
-    .eval_cookie = eap != NULL && eap->getline == getsourceline ? eap->cookie : NULL,
   };
+  if (eap != NULL && getline_equal(eap->getline, eap->cookie, getsourceline)) {
+    evalarg.eval_getline = eap->getline;
+    evalarg.eval_cookie = eap->cookie;
+  }
 
   if (skip) {
     emsg_skip++;
@@ -7461,8 +7464,11 @@ void ex_echo(exarg_T *eap)
 
   evalarg_T evalarg = {
     .eval_flags = eap->skip ? 0 : EVAL_EVALUATE,
-    .eval_cookie = eap->getline == getsourceline ? eap->cookie : NULL,
   };
+  if (getline_equal(eap->getline, eap->cookie, getsourceline)) {
+    evalarg.eval_getline = eap->getline;
+    evalarg.eval_cookie = eap->cookie;
+  }
 
   if (eap->skip) {
     emsg_skip++;
diff --git a/src/nvim/eval.h b/src/nvim/eval.h
index 4f517551c6..4e0eb6ebb8 100644
--- a/src/nvim/eval.h
+++ b/src/nvim/eval.h
@@ -272,7 +272,8 @@ typedef struct {
   int eval_flags;     ///< EVAL_ flag values below
 
   /// copied from exarg_T when "getline" is "getsourceline". Can be NULL.
-  void *eval_cookie;   // argument for getline()
+  LineGetter eval_getline;
+  void *eval_cookie;  ///< argument for eval_getline()
 
   /// pointer to the line obtained with getsourceline()
   char *eval_tofree;
@@ -284,7 +285,7 @@ enum {
 };
 
 /// Passed to an eval() function to enable evaluation.
-EXTERN evalarg_T EVALARG_EVALUATE INIT(= { EVAL_EVALUATE, NULL, NULL });
+EXTERN evalarg_T EVALARG_EVALUATE INIT(= { EVAL_EVALUATE, NULL, NULL, NULL });
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "eval.h.generated.h"
diff --git a/src/nvim/eval/vars.c b/src/nvim/eval/vars.c
index 868d03a115..4bce555d75 100644
--- a/src/nvim/eval/vars.c
+++ b/src/nvim/eval/vars.c
@@ -261,8 +261,11 @@ void ex_let(exarg_T *eap)
   }
   evalarg_T evalarg = {
     .eval_flags = eap->skip ? 0 : EVAL_EVALUATE,
-    .eval_cookie = eap->getline == getsourceline ? eap->cookie : NULL,
   };
+  if (getline_equal(eap->getline, eap->cookie, getsourceline)) {
+    evalarg.eval_getline = eap->getline;
+    evalarg.eval_cookie = eap->cookie;
+  }
   int eval_res = eval0(expr, &rettv, eap, &evalarg);
   if (eap->skip) {
     emsg_skip--;
diff --git a/src/nvim/ex_docmd.c b/src/nvim/ex_docmd.c
index f9f4a2514f..8e55672615 100644
--- a/src/nvim/ex_docmd.c
+++ b/src/nvim/ex_docmd.c
@@ -484,24 +484,6 @@ int do_cmdline(char *cmdline, LineGetter fgetline, void *cookie, int flags)
       }
     }
 
-    if (cstack.cs_looplevel > 0) {
-      // Inside a while/for loop we need to store the lines and use them
-      // again.  Pass a different "fgetline" function to do_one_cmd()
-      // below, so that it stores lines in or reads them from
-      // "lines_ga".  Makes it possible to define a function inside a
-      // while/for loop.
-      cmd_getline = get_loop_line;
-      cmd_cookie = (void *)&cmd_loop_cookie;
-      cmd_loop_cookie.lines_gap = &lines_ga;
-      cmd_loop_cookie.current_line = current_line;
-      cmd_loop_cookie.getline = fgetline;
-      cmd_loop_cookie.cookie = cookie;
-      cmd_loop_cookie.repeating = (current_line < lines_ga.ga_len);
-    } else {
-      cmd_getline = fgetline;
-      cmd_cookie = cookie;
-    }
-
     // 2. If no line given, get an allocated line with fgetline().
     if (next_cmdline == NULL) {
       // Need to set msg_didout for the first line after an ":if",
@@ -540,15 +522,37 @@ int do_cmdline(char *cmdline, LineGetter fgetline, void *cookie, int flags)
     }
     cmdline_copy = next_cmdline;
 
-    // Save the current line when inside a ":while" or ":for", and when
-    // the command looks like a ":while" or ":for", because we may need it
-    // later.  When there is a '|' and another command, it is stored
-    // separately, because we need to be able to jump back to it from an
+    int current_line_before = 0;
+    // Inside a while/for loop, and when the command looks like a ":while"
+    // or ":for", the line is stored, because we may need it later when
+    // looping.
+    //
+    // When there is a '|' and another command, it is stored separately,
+    // because we need to be able to jump back to it from an
     // :endwhile/:endfor.
-    if (current_line == lines_ga.ga_len
-        && (cstack.cs_looplevel || has_loop_cmd(next_cmdline))) {
-      store_loop_line(&lines_ga, next_cmdline);
+    //
+    // Pass a different "fgetline" function to do_one_cmd() below,
+    // that it stores lines in or reads them from "lines_ga".  Makes it
+    // possible to define a function inside a while/for loop.
+    if ((cstack.cs_looplevel > 0 || has_loop_cmd(next_cmdline))) {
+      cmd_getline = get_loop_line;
+      cmd_cookie = (void *)&cmd_loop_cookie;
+      cmd_loop_cookie.lines_gap = &lines_ga;
+      cmd_loop_cookie.current_line = current_line;
+      cmd_loop_cookie.getline = fgetline;
+      cmd_loop_cookie.cookie = cookie;
+      cmd_loop_cookie.repeating = (current_line < lines_ga.ga_len);
+
+      // Save the current line when encountering it the first time.
+      if (current_line == lines_ga.ga_len) {
+        store_loop_line(&lines_ga, next_cmdline);
+      }
+      current_line_before = current_line;
+    } else {
+      cmd_getline = fgetline;
+      cmd_cookie = cookie;
     }
+
     did_endif = false;
 
     if (count++ == 0) {
@@ -651,7 +655,7 @@ int do_cmdline(char *cmdline, LineGetter fgetline, void *cookie, int flags)
       } else if (cstack.cs_lflags & CSL_HAD_LOOP) {
         // For a ":while" or ":for" we need to remember the line number.
         cstack.cs_lflags &= ~CSL_HAD_LOOP;
-        cstack.cs_line[cstack.cs_idx] = current_line - 1;
+        cstack.cs_line[cstack.cs_idx] = current_line_before;
       }
     }