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// Copyright 2020 The Bazel Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
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package com.google.devtools.build.lib.buildtool;
import static com.google.common.truth.Truth.assertThat;
import com.google.common.collect.Iterables;
import com.google.devtools.build.lib.buildtool.util.BuildIntegrationTestCase;
import com.google.devtools.build.lib.vfs.Path;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;
/**
* Regression test for a stable inconsistent state.
*
* <p>This shows that the problem described in bug #730818 and discussed in the reviewlog for OCL
* 4645304 is fixed for the case where the inputs are known prior to execution (i.e. currently all
* actions except C++ compilation)--see testEditDuringBuild.
*
* <p>However, in the case of C++ compilation, since we don't know the inputs ahead of time, must
* stat the input files after execution, which leads to the race condition. The long term fix is to
* use a precise C++ dependency scanner and eliminate support for the {@code !inputsDiscovered()}
* case; in the meantime, things are unsound. Luckily, the risk is small, since it's only the clean
* build that is exposed to the problem, and the odds of editing a sourcefile just as it is being
* compiled is much smaller in a clean (long) build than in an incremental (short) build.
*/
@RunWith(JUnit4.class)
public class EditDuringBuildTest extends BuildIntegrationTestCase {
@Test
public void testEditDuringBuild() throws Exception {
Path in = write("edit/in", "line1");
in.setLastModifiedTime(123456789);
// Modify the actual source file, not a sandboxed copy.
addOptions("--spawn_strategy=local");
// The "echo" effects editing of the source file during the build:
write("edit/BUILD",
"genrule(name = 'edit',",
" srcs = ['in'],",
" outs = ['out'],",
" cmd = '/bin/cp $(location in) $(location out) && "
+ "echo line2 >>$(location in)')");
// Edit during build => undefined result (in fact, "line1")
String out = buildAndReadOutputFile();
assertThat(out).isEqualTo("line1\n");
// No edit during build => build should restore consistency.
out = buildAndReadOutputFile();
assertThat(out).isEqualTo("line1\nline2\n");
}
private String buildAndReadOutputFile() throws Exception {
buildTarget("//edit:out");
return readContentAsLatin1String(Iterables.getOnlyElement(getArtifacts("//edit:out")));
}
}