ninja not waiting for a dependent compile to finish before using its output artifact

[fischman]

I had this experience earlier today. up-enter re-running the same command to build chrome worked just fine. AFAICT the relevant .ninja file (https://gist.github.com/1981041) declares the dependency correctly.

ninja: Entering directory `ninja/Debug'
[1105/125/1015] AR obj/third_party/WebKit/Source/WebCore/WebCore.gyp/libwebcore_bindings.a
FAILED: rm -f obj/third_party/WebKit/Source/WebCore/WebCore.gyp/libwebcore_bindings.a && ar rcsT obj/third_party/WebKit/Source/WebCore/WebCore.gyp/libwebcore_bindings.a obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/bindings/webcore_bindings.V8DerivedSources01.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/bindings/webcore_bindings.V8DerivedSources02.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/bindings/webcore_bindings.V8DerivedSources03.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/bindings/webcore_bindings.V8DerivedSources04.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/bindings/webcore_bindings.V8DerivedSources05.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/bindings/webcore_bindings.V8DerivedSources06.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/bindings/webcore_bindings.V8DerivedSources07.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/bindings/webcore_bindings.V8DerivedSources08.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/bindings/webcore_bindings.V8DerivedSources09.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/bindings/webcore_bindings.V8DerivedSources10.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/bindings/webcore_bindings.V8DerivedSources11.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/bindings/webcore_bindings.V8DerivedSources12.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/bindings/webcore_bindings.V8DerivedSources13.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/bindings/webcore_bindings.V8DerivedSources14.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/bindings/webcore_bindings.V8DerivedSources15.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/bindings/webcore_bindings.V8DerivedSources16.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/bindings/webcore_bindings.V8DerivedSources17.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/bindings/webcore_bindings.V8DerivedSources18.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/bindings/webcore_bindings.V8DerivedSources19.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/webcore_bindings.ColorData.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/webcore_bindings.CSSPropertyNames.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/webcore_bindings.CSSValueKeywords.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/webcore_bindings.HTMLElementFactory.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/webcore_bindings.HTMLNames.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/webcore_bindings.EventFactory.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/webcore_bindings.ExceptionCodeDescription.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/webcore_bindings.UserAgentStyleSheetsData.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/webcore_bindings.V8HTMLElementWrapperFactory.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/webcore_bindings.XLinkNames.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/webcore_bindings.XMLNSNames.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/webcore_bindings.XMLNames.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/webcore_bindings.SVGNames.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/webcore_bindings.MathMLElementFactory.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/webcore_bindings.MathMLNames.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/webcore_bindings.WebKitFontFamilyNames.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/webcore_bindings.HTMLEntityTable.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/webcore_bindings.CSSGrammar.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/webcore_bindings.XPathGrammar.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webcore/webcore_bindings.InspectorFrontend.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webcore/webcore_bindings.InspectorBackendDispatcher.o obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webcore/webcore_bindings.InspectorTypeBuilder.o
ar: obj/third_party/WebKit/Source/WebCore/WebCore.gyp/gen/webkit/bindings/webcore_bindings.V8DerivedSources01.o: No such file or directory
[1105/0/1140] CXX obj/third_party/WebKit/Source/WebCore/testing/webcore_test_support.InternalSettings.o
ninja: build stopped: subcommand failed.

[evmar]

If it happens again, can you grab the tail of ninja/Debug/.ninja_log (the lines mentioning the files in question) to see if there's anything there?

I would expect this to fail more frequently if there was something significantly wrong with these deps, but that makes it even less clear as to why it just failed here.

[fischman]

Just happened again to another file; ninja output & log mentions of the file are in https://gist.github.com/1990680
It does look like the .o build is mentioned after the ar is.

[evmar]

Closing based on nobody complaining about this in a while. Please reopen if I'm wrong!