From 61696270eeebda7eeb5217f04f2ebe23f1293fd6 Mon Sep 17 00:00:00 2001
From: Laurent Perron <lperron@google.com>
Date: Fri, 2 Aug 2024 10:55:25 -0700
Subject: [PATCH] improve WriteMpsToFile

---
 ortools/linear_solver/BUILD.bazel       |  1 +
 ortools/linear_solver/model_exporter.cc | 20 +++++---------------
 ortools/linear_solver/model_exporter.h  | 21 +--------------------
 3 files changed, 7 insertions(+), 35 deletions(-)

diff --git a/ortools/linear_solver/BUILD.bazel b/ortools/linear_solver/BUILD.bazel
index 4d1b63d88e..618e1921a6 100644
--- a/ortools/linear_solver/BUILD.bazel
+++ b/ortools/linear_solver/BUILD.bazel
@@ -379,6 +379,7 @@ cc_library(
         "//ortools/base:file",
         "//ortools/base:hash",
         "//ortools/base:map_util",
+        "//ortools/base:status_macros",
         "//ortools/util:fp_utils",
         "@com_google_absl//absl/container:flat_hash_set",
         "@com_google_absl//absl/status",
diff --git a/ortools/linear_solver/model_exporter.cc b/ortools/linear_solver/model_exporter.cc
index 6a83c82c4c..51d75611d6 100644
--- a/ortools/linear_solver/model_exporter.cc
+++ b/ortools/linear_solver/model_exporter.cc
@@ -33,9 +33,10 @@
 #include "ortools/base/helpers.h"
 #include "ortools/base/logging.h"
 #include "ortools/base/options.h"
+#include "ortools/base/status_macros.h"
 #include "ortools/linear_solver/linear_solver.pb.h"
 
-ABSL_FLAG(bool, lp_log_invalid_name, false, "DEPRECATED.");
+ABSL_RETIRED_FLAG(bool, lp_log_invalid_name, false, "DEPRECATED.");
 
 namespace operations_research {
 namespace {
@@ -250,16 +251,9 @@ absl::StatusOr<std::string> ExportModelAsMpsFormat(
 absl::Status WriteModelToMpsFile(absl::string_view filename,
                                  const MPModelProto& model,
                                  const MPModelExportOptions& options) {
-  if (model.general_constraint_size() > 0) {
-    return absl::InvalidArgumentError("General constraints are not supported.");
-  }
-
-  MPModelProtoExporter exporter(model);
-  std::string mps_model;
-  if (!exporter.ExportModelAsMpsFormat(options, &mps_model)) {
-    return absl::InvalidArgumentError("Unable to export model.");
-  }
-  return file::SetContents(filename, mps_model, file::Defaults());
+  ASSIGN_OR_RETURN(std::string mps_data,
+                   ExportModelAsMpsFormat(model, options));
+  return file::SetContents(filename, mps_data, file::Defaults());
 }
 
 namespace {
@@ -478,10 +472,6 @@ void UpdateMaxSize(double new_number, int* size) {
 }  // namespace
 
 void MPModelProtoExporter::Setup() {
-  if (absl::GetFlag(FLAGS_lp_log_invalid_name)) {
-    LOG(WARNING) << "The \"lp_log_invalid_name\" flag is deprecated. Use "
-                    "MPModelProtoExportOptions instead.";
-  }
   num_binary_variables_ = 0;
   num_integer_variables_ = 0;
   for (const MPVariableProto& var : proto_.variable()) {
diff --git a/ortools/linear_solver/model_exporter.h b/ortools/linear_solver/model_exporter.h
index 6123b0b35e..ddf7b35040 100644
--- a/ortools/linear_solver/model_exporter.h
+++ b/ortools/linear_solver/model_exporter.h
@@ -101,26 +101,7 @@ absl::StatusOr<std::string> ExportModelAsMpsFormat(
  * Write the current model (variables, constraints, objective) to a file in MPS
  * file format, using the "free" MPS format.
  *
- * Returns false if some error has occurred during execution. Models with
- * maximization objectives trigger an error, because MPS can encode only
- * minimization problems.
- *
- * The validity of names is automatically checked. If a variable name or a
- * constraint name is invalid or non-existent, a new valid name is
- * automatically generated.
- *
- * Name validity and obfuscation works exactly as in ExportModelAsLpFormat().
- *
- * For more information about the MPS format:
- * http://en.wikipedia.org/wiki/MPS_(format)
- * A close-to-original description coming from OSL:
- * http://tinyurl.com/mps-format-by-osl
- * A recent description from CPLEX:
- * http://tinyurl.com/mps-format-by-cplex
- * CPLEX extensions:
- * http://tinyurl.com/mps-extensions-by-cplex
- * Gurobi's description:
- * http://www.gurobi.com/documentation/5.1/reference-manual/node869
+ * See ExportModelAsMpsFormat().
  */
 absl::Status WriteModelToMpsFile(
     absl::string_view filename, const MPModelProto& model,