Be more selective about deleting output files when interrupted

Specifically, only delete if the file was modified or if the rule uses
a depfile.

Fixes issue #226.

3 files changed, 78 insertions, 5 deletions

diff --git a/src/build.cc b/src/build.cc
index cd73487..44c1df6 100644
--- a/src/build.cc
+++ b/src/build.cc
@@ -521,16 +521,31 @@ Builder::Builder(State* state, const BuildConfig& config)
 }
 
 Builder::~Builder() {
+  Cleanup();
+}
+
+void Builder::Cleanup() {
   if (command_runner_.get()) {
     vector<Edge*> active_edges = command_runner_->GetActiveEdges();
     command_runner_->Abort();
 
     for (vector<Edge*>::iterator i = active_edges.begin();
          i != active_edges.end(); ++i) {
+      bool has_depfile = !(*i)->rule_->depfile().empty();
       for (vector<Node*>::iterator ni = (*i)->outputs_.begin();
-           ni != (*i)->outputs_.end(); ++ni)
-        disk_interface_->RemoveFile((*ni)->path());
-      if (!(*i)->rule_->depfile().empty())
+           ni != (*i)->outputs_.end(); ++ni) {
+        // Only delete this output if it was actually modified.  This is
+        // important for things like the generator where we don't want to
+        // delete the manifest file if we can avoid it.  But if the rule
+        // uses a depfile, always delete.  (Consider the case where we
+        // need to rebuild an output because of a modified header file
+        // mentioned in a depfile, and the command touches its depfile
+        // but is interrupted before it touches its output file.)
+        if (has_depfile ||
+            (*ni)->mtime() != disk_interface_->Stat((*ni)->path()))
+          disk_interface_->RemoveFile((*ni)->path());
+      }
+      if (has_depfile)
         disk_interface_->RemoveFile((*i)->EvaluateDepFile());
     }
   }
diff --git a/src/build.h b/src/build.h
index 778d59d..179fca6 100644
--- a/src/build.h
+++ b/src/build.h
@@ -116,6 +116,9 @@ struct Builder {
   Builder(State* state, const BuildConfig& config);
   ~Builder();
 
+  /// Clean up after interrupted commands by deleting output files.
+  void Cleanup();
+
   Node* AddTarget(const string& name, string* err);
 
   /// Add a target to the build, scanning dependencies.
diff --git a/src/build_test.cc b/src/build_test.cc
index 78bc918..ca74ab6 100644
--- a/src/build_test.cc
+++ b/src/build_test.cc
@@ -202,6 +202,8 @@ struct BuildTest : public StateTestWithBuiltinRules,
   virtual bool CanRunMore();
   virtual bool StartCommand(Edge* edge);
   virtual Edge* WaitForCommand(ExitStatus* status, string* output);
+  virtual vector<Edge*> GetActiveEdges(); 
+  virtual void Abort(); 
 
   BuildConfig MakeConfig() {
     BuildConfig config;
@@ -240,13 +242,15 @@ bool BuildTest::StartCommand(Edge* edge) {
   if (edge->rule().name() == "cat"  ||
       edge->rule().name() == "cat_rsp" ||
       edge->rule().name() == "cc" ||
-      edge->rule().name() == "touch") {
+      edge->rule().name() == "touch" ||
+      edge->rule().name() == "touch-interrupt") {
     for (vector<Node*>::iterator out = edge->outputs_.begin();
          out != edge->outputs_.end(); ++out) {
       fs_.Create((*out)->path(), now_, "");
     }
   } else if (edge->rule().name() == "true" ||
-             edge->rule().name() == "fail") {
+             edge->rule().name() == "fail" ||
+             edge->rule().name() == "interrupt") {
     // Don't do anything.
   } else {
     printf("unknown command\n");
@@ -259,6 +263,12 @@ bool BuildTest::StartCommand(Edge* edge) {
 
 Edge* BuildTest::WaitForCommand(ExitStatus* status, string* /* output */) {
   if (Edge* edge = last_command_) {
+    if (edge->rule().name() == "interrupt" ||
+        edge->rule().name() == "touch-interrupt") {
+      *status = ExitInterrupted;
+      return NULL;
+    }
+
     if (edge->rule().name() == "fail")
       *status = ExitFailure;
     else
@@ -270,6 +280,17 @@ Edge* BuildTest::WaitForCommand(ExitStatus* status, string* /* output */) {
   return NULL;
 }
 
+vector<Edge*> BuildTest::GetActiveEdges() {
+  vector<Edge*> edges;
+  if (last_command_)
+    edges.push_back(last_command_);
+  return edges;
+}
+
+void BuildTest::Abort() {
+  last_command_ = NULL;
+}
+
 TEST_F(BuildTest, NoWork) {
   string err;
   EXPECT_TRUE(builder_.AlreadyUpToDate());
@@ -941,3 +962,37 @@ TEST_F(BuildWithLogTest, RspFileCmdLineChange) {
   EXPECT_TRUE(builder_.Build(&err));
   EXPECT_EQ(1, commands_ran_.size());
 }
+
+TEST_F(BuildTest, InterruptCleanup) {
+  ASSERT_NO_FATAL_FAILURE(AssertParse(&state_,
+"rule interrupt\n"
+"  command = interrupt\n"
+"rule touch-interrupt\n"
+"  command = touch-interrupt\n"
+"build out1: interrupt in1\n"
+"build out2: touch-interrupt in2\n"));
+
+  fs_.Create("out1", now_, "");
+  fs_.Create("out2", now_, "");
+  now_++;
+  fs_.Create("in1", now_, "");
+  fs_.Create("in2", now_, "");
+
+  // An untouched output of an interrupted command should be retained.
+  string err;
+  EXPECT_TRUE(builder_.AddTarget("out1", &err));
+  EXPECT_EQ("", err);
+  EXPECT_FALSE(builder_.Build(&err));
+  EXPECT_EQ("interrupted by user", err);
+  builder_.Cleanup();
+  EXPECT_EQ(now_-1, fs_.Stat("out1"));
+  err = "";
+
+  // A touched output of an interrupted command should be deleted.
+  EXPECT_TRUE(builder_.AddTarget("out2", &err));
+  EXPECT_EQ("", err);
+  EXPECT_FALSE(builder_.Build(&err));
+  EXPECT_EQ("interrupted by user", err);
+  builder_.Cleanup();
+  EXPECT_EQ(0, fs_.Stat("out2"));
+}