Summary: This diff implements this for Field Not Initialized check
Reviewed By: artempyanykh
Differential Revision: D19393989
fbshipit-source-id: cf60e8d53
Summary: add subdirectories so that we can run each java file against its own topl properties
Reviewed By: rgrig
Differential Revision: D19347302
fbshipit-source-id: 562830774
Summary:
This diff does it for nullable dereference and assignment violations
rules which happen under NullsafeStrict case.
Follow up are to make the same for inheritance and field initializer
violations.
Possible follow up includes making error message more specific and
articulare this this is a nullsafe strict mode.
Reviewed By: artempyanykh
Differential Revision: D19392916
fbshipit-source-id: 2554ac7a7
Summary:
Previously, _override resolution_ considered only the number of
arguments. This led to many FPs in nullsafe's _Inconsistent Subclass
Annotation_ check.
Current version also checks that argument types match. However, we
still don't handle type parameters and erasure, so in this sense the
rules are incomplete.
Reviewed By: ngorogiannis, mityal
Differential Revision: D19393201
fbshipit-source-id: a0c75b8dd
Summary:
`diff` by default doesn't colorize its output, while `git diff`
does. Since we already depend on git it seems like a safe change and
brings some quality of life improvement while working with tests.
Reviewed By: ngorogiannis
Differential Revision: D19374691
fbshipit-source-id: 8872b527c
Summary:
`infer/tests/infer.make` unconditionally runs
```
$(call check_no_duplicates,$(INFER_OUT)/duplicates.txt)
```
as a part of `test` target. This requires the flag to be set to
produce `duplicates.txt`.
`clang.make` does this, but `java.make` was missing the flag which led
to an error on running `make tests` within
e.g. `tests/codetoanalyze/java/nullsafe-default`:
```
grep: infer-out/duplicates.txt: No such file or directory
```
Reviewed By: mityal
Differential Revision: D19373857
fbshipit-source-id: c2fcbe9dd
Summary:
This diff avoids that null-retuned path's abstract value ruins that of non-null-returned path.
What this diff does is: when joining two abstract states, one is null-return-path and the other is
non-null-return-path (`return obj;`), it keeps the method calls of `obj` from the
non-null-return-path.
While this design is unsound, I think it should work in practice.
Reviewed By: ezgicicek
Differential Revision: D19348313
fbshipit-source-id: cf5d0f3ff
Summary: This diff captures global initializers ondemand, like we do for functions defined in headers.
Reviewed By: ezgicicek
Differential Revision: D19346947
fbshipit-source-id: 05174e6a4
Summary:
Java treats switch on nullables in a non-obvious way (throws an NPE
surprise) so lets have a decidated test exactly for this.
Reviewed By: ngorogiannis
Differential Revision: D19371280
fbshipit-source-id: d9867b6d6
Summary:
Demonstrate that the per-file type environments don't prevent
the deadlock report here. The fear was that when the analyser
tries to locate the methods of the endpoint class, it might fail to
do so because the types might be stored in different type
environments (per file).
Reviewed By: mityal
Differential Revision: D19225908
fbshipit-source-id: 097e4aeea
Summary: This diff use actuall call path in the cost results instead of `class name + method name`.
Reviewed By: ngorogiannis
Differential Revision: D19194969
fbshipit-source-id: b72018586
Summary:
Model array length in Java as returning an unknown interval [0, +inf] for now.
Ideally, we can deal with the size in a more precise manner in the future like in InferBo.
Reviewed By: skcho
Differential Revision: D19312123
fbshipit-source-id: 8c51059a4
Summary: Pulse doesn't care about exceptions yet. With Exceptional CFG, java analysis takes a lot of time due to having many disjuncts. Let's use Normal CFG for now.
Reviewed By: jvillard
Differential Revision: D19194479
fbshipit-source-id: f94bb6078
Summary:
Kill these tests as that mode is not supported anymore.
Note that :
- "buck_cross_module" was effectively already dead since it's not hooked up to `make test`
- "buck" is actually another copy of "genrule" so wasn't testing anything
Reviewed By: ngorogiannis
Differential Revision: D19176166
fbshipit-source-id: b5bb90448
Summary:
This changes how we select amongst our (currently) 4 Buck integrations
for Java and clang, as well as how the user's choice is reflected by the
Config module.
The old command line interface is still supported but is now deprecated.
The changes in how to select each integration are:
- clang via "flavors", activated with `--flavors`, now with `--buck-clang`
- clang via "compilation DB", activated with `--buck-compilation-database`, unchanged
- Java via "genrule", activated with `--genrule-master-mode`, now with `--buck-java`
- Java "without genrules", used to be activated by *not specifying any other Buck mode*, unchanged
Instead of various `Config` flags corresponding to the previous CLI that
are allowed in any combination of `flavors`,
`buck_compilation_database`, `genrule_master_mode`, `Config` now exposes
a single `buck_mode` datatype. This allows, eg, `flavors` to override
`buck_compilation_database` if needed. It will also make it easier to
get rid of the old "Java without genrules" integration in a later diff
(see inline comments).
Reviewed By: ngorogiannis
Differential Revision: D19175686
fbshipit-source-id: 29b3831be
Summary:
In order to improve the impurity analysis, this diff adds models for
- `hasNext()` and - `Object.equals()` modeled as returning a non-deterministic value (havoc_id)
- `next()` modeled as `StdVector.get` with a fresh index
- `iterator` modeled as just returning the underlying list
Reviewed By: jvillard
Differential Revision: D19177392
fbshipit-source-id: 0babb037a
Summary:
This diff updates the relation between iterator (offset) and integer value not only at
assignments (`x += 1`), but also at function calls (`foo()`) that increase integer values by one in
their side effects.
Reviewed By: ezgicicek
Differential Revision: D19163214
fbshipit-source-id: 47e52f939
Summary: This diff extends the domain to express the relation between iterator's offset and integer value.
Reviewed By: ezgicicek
Differential Revision: D19143670
fbshipit-source-id: 6223bc934
Summary:
Old versions of sawja/javalib got the line numbers slightly wrong. The workaround was to do a regexp search in the source file for the right line.
My understanding is that this is no longer necessary. This diff removes it.
Reviewed By: jvillard
Differential Revision: D19033415
fbshipit-source-id: 2da19d66d
Summary:
This is an optimization. We ask the user to tell us which states are nondeterministic, and we
generate code that handle nondeterminism only for those states. It is common for only one state per
TOPL property to be nondeterministic. This speeds up the biabduction-analysis of the monitor by a
factor of ~10. But, using the monitor is only a little faster.
Facebook
Reviewed By: jvillard
Differential Revision: D19160286
fbshipit-source-id: 4dd39769a
Summary:
In the previous code, it removed non-build-called method calls. For example, it was like
```
{non-build-called: {prop1, prop3}}
{build-called: {}}
b.build();
{non-build-called: {}}
{build-called: {prop1, prop3}}
```
However, this behavior introduced a false positive when there is multiple builders that point to the
same abstract object and `build` is called one by one.
This diff changes the semantics to keep the method calls of non-build-called at `build` calls.
Reviewed By: ezgicicek
Differential Revision: D19144525
fbshipit-source-id: e2ace127f
Summary:
This applies some simplifications that were previously
done after footprint (and therefore lost), and some
simplifications that require looking at both pre and
post.
Reviewed By: ngorogiannis
Differential Revision: D19035494
fbshipit-source-id: bad79534a
Summary:
This havocs event data, so that biabduction doesn't try to
track what was the last event processed by the monitor
(which is redundant as long as the state of the monitor
is tracked).
Reviewed By: ngorogiannis
Differential Revision: D19035491
fbshipit-source-id: a1c75daae
Summary:
Don't instrument SIL when we can determine statically that
biabduction symexec would be a no-op.
Reviewed By: ngorogiannis
Differential Revision: D19116849
fbshipit-source-id: 4d25462a3
Summary: It is confusing to report missing props at the the beginning of the method (especially when there are many components created or when the method has many lines). Let's report them at create methods to better contextualize. Also, make the missing prop bold.
Reviewed By: skcho
Differential Revision: D19141135
fbshipit-source-id: a23d2e7c9
Summary:
In addition to
state1 -> state2: pattern
one can now also write
state1 -> state2: pattern if condition
where "condition" is some conjunction of comparisons (==,<,>) that
involve variables bound by "pattern", registers of the automaton, and
constants.
Reviewed By: ngorogiannis
Differential Revision: D19035496
fbshipit-source-id: 6f6e6a9be
Summary:
According to Java semantics, they are always non-null.
Internally they are represented as static fields, so they have
DeclaredNonnull nullability, which means NullsafeStrict mode would
refuse to use them without strictification.
Lets teach nullsafe that these guys are non-nullables.
See also FN in test case.
Reviewed By: ngorogiannis
Differential Revision: D19024547
fbshipit-source-id: 8c120fa50
Summary:
We do not have the create method in the trace which makes it difficult to understand
- inter-procedural issues where create and prop setting are in different methods
- there are multiple create-build chains in a method
Let's add the create to the beginning of the trace. Moreover, let's simplify the prop printing to make traces easier to understand.
Reviewed By: ngorogiannis
Differential Revision: D19020213
fbshipit-source-id: 7f8a5d4ec
Summary: The new domain is much better than the old one. Let's kill the old one (along with old litho tests) and simplify things.
Reviewed By: skcho
Differential Revision: D18959627
fbshipit-source-id: df77ae20e
Summary:
In order to handle the example added:
changed domain of `MethodCalled`
from `CreatedLocation -> (IsBuildCalled X IsChecked X Set(MethodCall))`
to `(CreatedLocation X IsBuildCalled) -> (IsChecked X Set(MethodCall))`
This avoids joining of two method calls where one is build-called and the other is not, e.g.,
```
if(b) {
o.build();
} else {
// no build call
}
```
changed domain of `NewDomain`
from `Created X MethodCalled`
to `(Created X MethodCalled) X (Created X MethodCalled)`
One is for no returned memory and the other is returned memory. This keeps precision some join
points of branches, e.g.,
```
if(b) {
return;
} else {
// no return
}
```
Reviewed By: ezgicicek
Differential Revision: D18909768
fbshipit-source-id: c39d1a1ef
Summary:
A plus is a plus, no need to give up when +/- is about pointers. This
gets rid of some false positives involving pointer arithmetic.
However, the problem remains if we make things a bit more
inter-procedural. This is documented in an added test.
Reviewed By: ezgicicek
Differential Revision: D18932877
fbshipit-source-id: 4ad1cfe72
Summary: It is not used anywhere and there are no plans to revive it. Kill it!
Reviewed By: skcho
Differential Revision: D18934719
fbshipit-source-id: b9b069b96
Summary:
The `Typ.FIeldname` module has many issues. Among those:
- It has 5 different string/printing functions and most of them do radically different things in Java and in Clang.
- There is no type safety: creating a Clang field and calling a Java function on it will lead to a crash (`rindex_exn` etc, there are usually no dots in Clang fields).
- It uses a single string for Java fields, containing the package, the class and the field, e.g., `java.lang.Object.field`. This is wasteful, because
- there is no sharing of strings for packages/classes, and,
- string operations need to be performed every time we need the field or the class or the package alone.
This diff preserves the behaviour of the module's interface, so the API problems remain.
However, by using a saner representation for Java fields we can get small performance and large memory gains (the type environment in Java is much smaller, about 30-40%).
In addition, many functions on clang fields would previously do string manipulations (look for `.` and split on it) before returning the final field unchanged -- now they use the type of the field for that.
Reviewed By: jvillard
Differential Revision: D18908864
fbshipit-source-id: a72d847cc
Summary:
- Do most of the work of `solve_arithmetic_constraints` inside `subst_attribute` instead, since we need to re-use the latter function for post-conditions where the first function is not appropriate.
- When substituting arithmetic constraints, we refine arithmetic information (both concrete intervals and inferbo), which can lead to inconsistent states. Instead of recording the new arithmetic facts by returning a new current state, just act as a map on attributes. This is to enable doing the point above.
- All this lead to a somewhat messy refactoring...
- Rename `CannotApplyPre` to `Contradiction` since it's used for post-conditions as well now
Reviewed By: skcho
Differential Revision: D18889120
fbshipit-source-id: d81647143
Summary: Guava uses assertions to ensure a future can be gotten without blocking (this means that if the future is not done, the app will crash). This diff teaches the starvation analyser about a number of such assertions, by treating them as assumes (since we don't care about exceptions).
Reviewed By: jvillard
Differential Revision: D18893427
fbshipit-source-id: 4d26a202b
Summary: A future is guaranteed not to block if `isDone()` has returned true first. Add logic for supporting that by remembering the objects that we have called `isDone` on and by making `assume` do the right thing with that knowledge. All this is achieved with the attribute domain.
Reviewed By: ezgicicek
Differential Revision: D18833901
fbshipit-source-id: 7f4ea0cd1
Summary:
When retrieving a value from a container, we previously had an arbitrary hack which would
- In java, give no ownership to the returned object (trying to be sound)
- In C++ give conditional ownership to the current method's first argument (trying to be complete, but doing it badly, as the first argument may not be the `this` object in a static method, or we might be accessing it through another parameter altogether).
Harmonise both by using the existing ownership of the container as ownership value for the returned object (leaning towards completeness).
Reviewed By: jvillard
Differential Revision: D18882800
fbshipit-source-id: f98f8d315
Summary:
Pointers are hard... The previous test had no chance of doing
initialisation of the pointer by reference and was in fact a false
negative (and still is, fix incoming). Renamed functions to stress the
false negative and added a test that is really (potentially) doing
pointer initialisation by reference.
Reviewed By: skcho
Differential Revision: D18888008
fbshipit-source-id: 1e72408c7
Summary:
This reverts commit 4fd6165d190bab32544f9f040b777565432c15b2.
We don't need to check for reporting each node anymore. It suffices to just check per function.
Reviewed By: skcho
Differential Revision: D18883833
fbshipit-source-id: 2591b3af3
Summary:
Making `MethodCalled` an inverted map from created location to method calls results in not being able to track a builder that is created in two different branches of a conditional with different types. Instead, we can make `MethodCalled` simply a map and also change `Created` to be a map from access paths to a set of created locations.
To deal with the case of setting a prop only in one branch, we need to ensure that whenever we call a create method, we add a binding to `MethodCalled` with an empty list of methods so that its intersection with a non-empty one is empty.
Reviewed By: skcho
Differential Revision: D18883097
fbshipit-source-id: b3464ca20
Summary: As long as the types match, it should be possible to call build on two components that are created at different locations.
Reviewed By: skcho
Differential Revision: D18881740
fbshipit-source-id: 356f9e168
Summary:
Finally use information from the inferbo intervals in pulse's domain to
make decisions about whether conditionals are feasible or not.
Reviewed By: skcho
Differential Revision: D18811193
fbshipit-source-id: d80a28657
Summary: Add a FN that is detected by the old domain but not the new one
Reviewed By: ngorogiannis
Differential Revision: D18854389
fbshipit-source-id: 9bdc90a6b
Summary: The map from `CreatedLocation` to `MethodCalls` already takes care of the association from create methods to their set props. `MethodCall` comparison should be oblivious the the receiver, otherwise, we risk mistakenly considering two props set at different locations as different.
Reviewed By: skcho
Differential Revision: D18829388
fbshipit-source-id: b5a0d628d
Summary: This diff check and report on every nodes. Problem of the previous design is that it has to report alarms only with the abstract memory of the exit node. However, the new abstract value becomes imprecise at every join points on the path to the exit node, since it is using inverted map, i.e., under-approximation on collecting called methods. As a solution, this diff report on every nodes where `.build` is called with the abstract memory at that node.
Reviewed By: ezgicicek
Differential Revision: D18809449
fbshipit-source-id: 4fd6165d1
Summary: Current method call comparison is too strong. As exemplified with the new test, one can also set the required prop by calling a version which contains the suffixes. The domain should take care of such cases now.
Reviewed By: skcho
Differential Revision: D18808869
fbshipit-source-id: 9f7672e75
Summary:
Sometimes clang9 does not return a boxing method (a name of function to apply), e.g., [@("str")].
To solve the issue, this diff uses "unknownSelector:" instead of giving up the translation.
Reviewed By: dulmarod
Differential Revision: D18831844
fbshipit-source-id: b9324ba39
Summary: This diff checks litho condition on the new abstract value. This is triggered with `--new-litho-domain`, but it is intra-procedural as of now.
Reviewed By: ezgicicek
Differential Revision: D18783203
fbshipit-source-id: 98570104e
Summary:
Also add logic for recognising excessive timeouts. Refactor the code
around timeouts a little.
Reviewed By: artempyanykh
Differential Revision: D18807836
fbshipit-source-id: df5a1b566
Summary:
`Object.wait()` must be called on a locked monitor and it releases the
lock immediately, as far as other threads are concerned
(it also magically re-takes the lock when the monitor is `notified`).
Starvation can only occur if the UI thread is waiting
a lock that is distinct to that being waited on.
The check present was over-approximate in that it was checking that there exists a lock held by the UI thread and the thread issuing the `wait`, but did not make sure that lock was *not* the one waited on.
Amusingly, the e2e test was correct, but the reporting code wasn't.
Reviewed By: dulmarod
Differential Revision: D18782919
fbshipit-source-id: b3b98239e
Summary: The clang plugin exports C++ mangled names in hashed form for perf reasons, so we need to hash the incoming mangled names in the profiler samples, so that we can compare them.
Reviewed By: skcho
Differential Revision: D18761842
fbshipit-source-id: 3072b5e33
Summary: Similar to constructor established attributes, we do the same here for static initializers. That is, attributes of static properties are injected into the initial state of every method.
Reviewed By: ezgicicek
Differential Revision: D18763192
fbshipit-source-id: 3879a27c5
Summary: Raises an error when weakSelf is used multiple times in a block. The issue is that there could be unexpected behaviour. Even if `weakSelf` is not nil in the first use, it could be nil in the following uses since the object that `weakSelf` points to could be freed anytime.
Reviewed By: skcho
Differential Revision: D18765493
fbshipit-source-id: 37fc652e3
Summary: This diff extends the bound domain to express multiplication of bounds in some simple cases.
Reviewed By: ezgicicek
Differential Revision: D18745246
fbshipit-source-id: 4f2dcb42c
Summary:
One standard way to schedule work is by starting a thread. We treat this by
- Treating invocations of `start` on a receiver with the `Runnable _` attribute as scheduling that runnable for parallel execution in the background (as opposed to on the UI thread).
- If `start` is used on an object of a subclass of `Thread` everything already works thanks to the `get_exp_attributes` function which will implicitly ascribe to an expression the attribute `Runnable _` if the expression points to an object with a known `run` method. This will even take care of some degree of dynamic dispatch, yay!
- If `start` is used on a `Thread` object which has been created with a constructor call provided with a `Runnable` argument, we have to appropriately model that constructor call, which is what is done in `do_call`.
Reviewed By: jvillard
Differential Revision: D18726676
fbshipit-source-id: 0bd83c28e
Summary:
A current blind spot is when object construction stores specific executors / runnables to object fields, which are then never mutated and accessed from normal methods. IOW the attributes established in the constructor are necessary to report properly inside a normal method (assuming these attributes are not invalidated by method code).
To achieve this, first we retain a subset of the final state attributes in the summary (only those that affect instance variables, in constructor methods). Then, when we analyse a non-constructor method:
- we analyse all constructors
- remove all attributes from the attribute map whose key is not an expression of the form `this.x. ...`
- re-localise all remaining keys so that they appear as rooted in the `this` local variable of the current procedure
- join (intersect) all such attribute maps
- use the result in place of initial state as far as the attribute map is concerned for the analysis of the current procedure, which can now start.
This means we can catch idioms that use side-effectful initialisation for configuring certain object fields like executors or runnables.
Reviewed By: jvillard
Differential Revision: D18707890
fbshipit-source-id: 42ac6108f
Summary: Another way to schedule work in android is by posting it to a `Handler`. A handler can be constructed out of the main looper, which forces it to schedule work on the UI thread. To model all this, we add syntactic models for getting the main looper and for creating handlers, and dataflow attributes for tracking that an expression is a looper/the main looper, or a handler constructed out of a looper.
Reviewed By: skcho
Differential Revision: D18706768
fbshipit-source-id: 7c46e6913
Summary:
New syntax f1 AND-WITH-WITNESSES f2 : predicate_on_both_witnesses()
This is needed for a linter to check that a macro is present, see the test.
Reviewed By: skcho
Differential Revision: D18735988
fbshipit-source-id: a3be75c5e
Summary:
This gets rid of false positives when something invalid (eg null) is
passed by reference to an initialisation function. Havoc'ing what the
contents of the pointer to results in being optimistic about said
contents in the future.
Also surprisingly gets rid of some FNs (which means it can also
introduce FPs) in the `std::atomic` tests because a path condition
becomes feasible with havoc'ing.
There's a slight refinement possible where we don't havoc pointers to
const but that's more involved and left as future work.
Reviewed By: skcho
Differential Revision: D18726203
fbshipit-source-id: 264b5daeb
Summary:
It's a well-known fact that pulse should know too. To avoid splitting
the abstract state systematically, only act if we know the pointer is
exactly 0 to avoid reporting a nullptr dereference on `free(x)`.
Reviewed By: ezgicicek
Differential Revision: D18708575
fbshipit-source-id: 1cc3f6908
Summary:
Turns out code uses atomics in important places, modelling it removes
FPs.
The tests are copied from biabduction and adapted and extended a bit. I
didn't implement compare_exchange primitives for now (plus, giving them
a sequential semantics like in biabduction is probably a bit cheeky).
Reviewed By: skcho
Differential Revision: D18708576
fbshipit-source-id: a3581b8a4
Summary:
This diff adds inferbo's interval values to pulse's attributes. The added values will be used to
filter out infeasible passes in the following diffs.
Reviewed By: jvillard
Differential Revision: D18726667
fbshipit-source-id: c1125ac6e
Summary:
This diff fixes the model of substring.
Problem: The cost model of the substring function was to return `size of string - start index` as a
cost. However, sometimes this was a negative number, because of state abstractions on paths, array
elements, call contexts, etc, which caused an exception inadvertently.
This diff changes the model to return just `size of string`, when it cannot say `size of string` is
bigger than `start index`.
Reviewed By: ezgicicek
Differential Revision: D18707954
fbshipit-source-id: 63f27e461
Summary:
Instead of trying to figure out what runnable is directly passed to an executor,
use attributes to track the flow of a runnable. This has several advantages:
- Can track runnables across function return values.
- Can somewhat overcome the information loss under dynamic dispatch.
- Unifies handling with other attributes.
Reviewed By: skcho
Differential Revision: D18672676
fbshipit-source-id: a06a0e6ff
Summary:
- Unify treatment of modelled and annotated executors by making things go through attributes.
- Add a return attribute to summaries, so that we can track flows of thread guards/executors/future stuff through returned values.
- Dispatch modeled functions to model summaries.
This will help in following diffs where runnables will also go through attributes.
Reviewed By: skcho
Differential Revision: D18660185
fbshipit-source-id: e26b1083e
Summary:
A plugin update allows infer to know when a function doesn't return
according to its attributes. This propagates this info all the way to
the attributes of each function, and then use this information in a new
pre-analysis that cuts the links to successor nodes of each `Call`
instruction to a function that does not return.
NOTE: The "no_return" `CallFlag.t` was dead code, following diffs deal
with that (by removing it).
Reviewed By: dulmarod
Differential Revision: D18573922
fbshipit-source-id: 85ec64eca
Summary:
This also prints the CFGs *after* pre-analysis for individual procedures
in infer-out/captured/<filename>/<proc>.dot. One can also look up the
CFGs before pre-analysis in infer-out/captured/proc_cfgs_frontend.dot.
Context: I want to add a pre-analysis that needs to look at proc
attributes inter-procedurally. For this to make sense it has to happen
*after* all of capture, and before analysis.
Thus, this diff brings back the lazy running of the pre-analysis like in
D15803492, except that we still make sure to run the pre-analyses
systematically regardless of the checkers being run by running the
pre-analysis from ondemand.ml. Also we don't need to re-introduce the
"did_preanalysis" proc attribute for the same reason that the
pre-analysis is now run once and for all by ondemand.ml (instead of each
individual checker back in the days).
This has the benefit of running the pre-analysis only when needed, and
the drawback that several concurrent processes analysing the same proc
descs will duplicate work. Since pre-analyses are supposed to be very
fast I assume that neither is a big deal. If they become more expensive
then the benefit gets bigger and the drawback is just the same as with
regular analyses.
Reviewed By: skcho
Differential Revision: D18573920
fbshipit-source-id: de350eaef
Summary: This diff get static value with `EMPTY` field from class initializer.
Reviewed By: ngorogiannis
Differential Revision: D18616588
fbshipit-source-id: 26414c9b2
Summary: When we see a call to schedule some work on an executor and we don't have evidence that it is on some specific thread (UI/BG), instead of dropping the work, assign it `UnknownThread` and treat it as running on the background by default.
Reviewed By: jvillard
Differential Revision: D18615649
fbshipit-source-id: e8bad64b6
Mitya Lyubarskiy
Jules Villard
Artem Pianykh
Sungkeun Cho
Ezgi Çiçek
Kfir Schindelhaim
Nikos Gorogiannis
Radu Grigore
Martin Trojer
Dulma Churchill