From e51c449fe60bf31456bc93c42bec1f2070e688d0 Mon Sep 17 00:00:00 2001
From: Victor Zverovich <viz@fb.com>
Date: Sat, 25 Apr 2020 07:43:56 -0700
Subject: [PATCH] Revert "Check dynamic widht/precision id at compile time
 (#1614)"

This reverts commit 7d748a6f826a14d44b7fe5007b37461d5dbb78fd.
---
 include/fmt/core.h   | 27 +++++++--------------------
 include/fmt/format.h |  8 +++++++-
 test/format-test.cc  |  2 --
 3 files changed, 14 insertions(+), 23 deletions(-)

diff --git a/include/fmt/core.h b/include/fmt/core.h
index 857dcc05..a543f096 100644
--- a/include/fmt/core.h
+++ b/include/fmt/core.h
@@ -8,7 +8,6 @@
 #ifndef FMT_CORE_H_
 #define FMT_CORE_H_
 
-#include <climits>
 #include <cstdio>  // std::FILE
 #include <cstring>
 #include <functional>
@@ -563,24 +562,14 @@ class basic_format_parse_context : private ErrorHandler {
  private:
   basic_string_view<Char> format_str_;
   int next_arg_id_;
-  int num_args_;
-
-  FMT_CONSTEXPR int do_check_arg_id(int id) {
-    if (id >= num_args_) on_error("argument not found");
-    return id;
-  }
 
  public:
   using char_type = Char;
   using iterator = typename basic_string_view<Char>::iterator;
 
   explicit FMT_CONSTEXPR basic_format_parse_context(
-      basic_string_view<Char> format_str, int num_args = INT_MAX,
-      ErrorHandler eh = {})
-      : ErrorHandler(eh),
-        format_str_(format_str),
-        next_arg_id_(0),
-        num_args_(num_args) {}
+      basic_string_view<Char> format_str, ErrorHandler eh = ErrorHandler())
+      : ErrorHandler(eh), format_str_(format_str), next_arg_id_(0) {}
 
   /**
     Returns an iterator to the beginning of the format string range being
@@ -605,7 +594,7 @@ class basic_format_parse_context : private ErrorHandler {
     the next argument index and switches to the automatic indexing.
    */
   FMT_CONSTEXPR int next_arg_id() {
-    if (next_arg_id_ >= 0) return do_check_arg_id(next_arg_id_++);
+    if (next_arg_id_ >= 0) return next_arg_id_++;
     on_error("cannot switch from manual to automatic argument indexing");
     return 0;
   }
@@ -614,13 +603,11 @@ class basic_format_parse_context : private ErrorHandler {
     Reports an error if using the automatic argument indexing; otherwise
     switches to the manual indexing.
    */
-  FMT_CONSTEXPR void check_arg_id(int id) {
-    if (next_arg_id_ > 0) {
+  FMT_CONSTEXPR void check_arg_id(int) {
+    if (next_arg_id_ > 0)
       on_error("cannot switch from automatic to manual argument indexing");
-      return;
-    }
-    do_check_arg_id(id);
-    next_arg_id_ = -1;
+    else
+      next_arg_id_ = -1;
   }
 
   FMT_CONSTEXPR void check_arg_id(basic_string_view<Char>) {}
diff --git a/include/fmt/format.h b/include/fmt/format.h
index 56bcf191..d11a714b 100644
--- a/include/fmt/format.h
+++ b/include/fmt/format.h
@@ -2632,17 +2632,19 @@ class format_string_checker {
   explicit FMT_CONSTEXPR format_string_checker(
       basic_string_view<Char> format_str, ErrorHandler eh)
       : arg_id_(-1),
-        context_(format_str, num_args, eh),
+        context_(format_str, eh),
         parse_funcs_{&parse_format_specs<Args, parse_context_type>...} {}
 
   FMT_CONSTEXPR void on_text(const Char*, const Char*) {}
 
   FMT_CONSTEXPR void on_arg_id() {
     arg_id_ = context_.next_arg_id();
+    check_arg_id();
   }
   FMT_CONSTEXPR void on_arg_id(int id) {
     arg_id_ = id;
     context_.check_arg_id(id);
+    check_arg_id();
   }
   FMT_CONSTEXPR void on_arg_id(basic_string_view<Char>) {
     on_error("compile-time checks don't support named arguments");
@@ -2663,6 +2665,10 @@ class format_string_checker {
   using parse_context_type = basic_format_parse_context<Char, ErrorHandler>;
   enum { num_args = sizeof...(Args) };
 
+  FMT_CONSTEXPR void check_arg_id() {
+    if (arg_id_ >= num_args) context_.on_error("argument not found");
+  }
+
   // Format specifier parsing function.
   using parse_func = const Char* (*)(parse_context_type&);
 
diff --git a/test/format-test.cc b/test/format-test.cc
index f9e75d20..fa3574bc 100644
--- a/test/format-test.cc
+++ b/test/format-test.cc
@@ -2493,8 +2493,6 @@ TEST(FormatTest, FormatStringErrors) {
   EXPECT_ERROR("{:+}", "format specifier requires signed argument", unsigned);
   EXPECT_ERROR("{:-}", "format specifier requires signed argument", unsigned);
   EXPECT_ERROR("{: }", "format specifier requires signed argument", unsigned);
-  EXPECT_ERROR("{:{}}", "argument not found", int);
-  EXPECT_ERROR("{:.{}}", "argument not found", double);
   EXPECT_ERROR("{:.2}", "precision not allowed for this argument type", int);
   EXPECT_ERROR("{:s}", "invalid type specifier", int);
   EXPECT_ERROR("{:s}", "invalid type specifier", bool);