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Python points-to: Add objects representing missing modules and their attributes.
1 parent b10a7cd commit bf78c62

19 files changed

Lines changed: 252 additions & 18 deletions

‎python/ql/src/semmle/python/objects/Modules.qll‎

Lines changed: 153 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -250,3 +250,156 @@ class PythonModuleObjectInternal extends ModuleObjectInternal, TPythonModule {
250250

251251
}
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253+
class AbsentModuleObjectInternal extends ModuleObjectInternal, TAbsentModule {
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override Builtin getBuiltin() {
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none()
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}
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override string toString() {
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if exists(Module m, SyntaxError se | se.getFile() = m.getFile() and m.getName() = this.getName()) then
261+
result = "Unparsable module " + this.getName()
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else
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result = "Missing module " + this.getName()
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}
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override string getName() {
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this = TAbsentModule(result)
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}
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override predicate introduced(ControlFlowNode node, PointsToContext context) {
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missing_imported_module(node, context, this.getName())
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}
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override ClassDecl getClassDeclaration() {
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none()
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}
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override Module getSourceModule() {
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none()
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}
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PythonModuleObjectInternal getInitModule() {
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none()
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}
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override int intValue() {
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none()
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}
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override string strValue() {
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none()
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}
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override predicate calleeAndOffset(Function scope, int paramOffset) {
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none()
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}
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pragma [noinline] override predicate attribute(string name, ObjectInternal value, CfgOrigin origin) {
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value = TAbsentModuleAttribute(this, name) and origin = CfgOrigin::unknown()
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}
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pragma [noinline] override predicate attributesUnknown() { none() }
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override ControlFlowNode getOrigin() {
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none()
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}
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override predicate isMissing() {
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any()
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}
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}
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class AbsentModuleAttributeObjectInternal extends ObjectInternal, TAbsentModuleAttribute {
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override Builtin getBuiltin() {
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none()
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}
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override string toString() {
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exists(ModuleObjectInternal mod, string name |
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this = TAbsentModuleAttribute(mod, name) and
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result = "Missing module attribute " + mod.getName() + "." + name
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)
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}
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override predicate introduced(ControlFlowNode node, PointsToContext context) {
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exists(ModuleObjectInternal mod, string name |
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this = TAbsentModuleAttribute(mod, name) |
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PointsToInternal::pointsTo(node.(AttrNode).getObject(name), context, mod, _)
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or
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PointsToInternal::pointsTo(node.(ImportMemberNode).getModule(name), context, mod, _)
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)
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}
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override ClassDecl getClassDeclaration() {
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none()
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}
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PythonModuleObjectInternal getInitModule() {
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none()
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}
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override int intValue() {
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none()
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}
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override string strValue() {
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none()
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}
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override predicate calleeAndOffset(Function scope, int paramOffset) {
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none()
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}
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pragma [noinline] override predicate attribute(string name, ObjectInternal value, CfgOrigin origin) {
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none()
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}
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pragma [noinline] override predicate attributesUnknown() { any() }
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override ControlFlowNode getOrigin() {
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none()
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}
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override predicate callResult(ObjectInternal obj, CfgOrigin origin) {
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// Don't know, assume not callable.
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none()
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}
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override predicate callResult(PointsToContext callee, ObjectInternal obj, CfgOrigin origin) {
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// Don't know, assume not callable.
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none()
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}
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override boolean isClass() { result = maybe() }
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override boolean isComparable() { result = false }
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override boolean booleanValue() {
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result = maybe()
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}
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override ObjectInternal getClass() {
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result = ObjectInternal::unknownClass()
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}
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override boolean isDescriptor() { result = false }
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override predicate descriptorGetClass(ObjectInternal cls, ObjectInternal value, CfgOrigin origin) { none() }
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override predicate descriptorGetInstance(ObjectInternal instance, ObjectInternal value, CfgOrigin origin) { none() }
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override predicate binds(ObjectInternal instance, string name, ObjectInternal descriptor) { none() }
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override int length() { none() }
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override predicate subscriptUnknown() { any() }
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override predicate isMissing() {
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any()
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}
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}
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‎python/ql/src/semmle/python/objects/ObjectAPI.qll‎

Lines changed: 9 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -56,6 +56,15 @@ class Value extends TObject {
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predicate isBuiltin() {
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this.(ObjectInternal).isBuiltin()
5858
}
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/** Holds if this value represents an entity that is inferred to exist,
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* but missing from the database.
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* Most commonly, this is a module that is imported, but wasn't present during extraction.
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*/
64+
predicate isMissing() {
65+
this.(ObjectInternal).isMissing()
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}
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5968
}
6069

6170
class ModuleValue extends Value {

‎python/ql/src/semmle/python/objects/ObjectInternal.qll‎

Lines changed: 6 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -111,6 +111,12 @@ class ObjectInternal extends TObject {
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112112
predicate functionAndOffset(CallableObjectInternal function, int offset) { none() }
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114+
/** Holds if this 'object' represents an entity that is inferred to exist
115+
* but is missing from the database */
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predicate isMissing() {
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none()
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}
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}
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‎python/ql/src/semmle/python/objects/TObject.qll‎

Lines changed: 44 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -39,7 +39,9 @@ newtype TObject =
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exists(moduleNameFromFile(f))
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}
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or
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TPythonModule(Module m) { not m.isPackage() }
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TPythonModule(Module m) {
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not m.isPackage() and not exists(SyntaxError se | se.getFile() = m.getFile())
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}
4345
or
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TTrue()
4547
or
@@ -160,6 +162,23 @@ newtype TObject =
160162
}
161163
or
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TSysVersionInfo()
165+
or
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TAbsentModule(string name) {
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missing_imported_module(_, _, name)
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}
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or
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TAbsentModuleAttribute(AbsentModuleObjectInternal mod, string attrname) {
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(
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PointsToInternal::pointsTo(any(AttrNode attr).getObject(attrname), _, mod, _)
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or
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PointsToInternal::pointsTo(any(ImportMemberNode imp).getModule(attrname), _, mod, _)
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)
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and
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exists(string modname |
178+
modname = mod.getName() and
179+
not common_module_name(modname + "." + attrname)
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)
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}
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164183
private predicate is_power_2(int n) {
165184
n = 1 or
@@ -327,6 +346,30 @@ private predicate neither_class_nor_static_method(Function f) {
327346
)
328347
}
329348

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predicate missing_imported_module(ControlFlowNode imp, Context ctx, string name) {
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ctx.isImport() and imp.(ImportExprNode).getNode().getAnImportedModuleName() = name and
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(
352+
not exists(Module m | m.getName() = name) and
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not exists(Builtin b | b.isModule() and b.getName() = name)
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or
355+
exists(Module m, SyntaxError se |
356+
m.getName() = name and
357+
se.getFile() = m.getFile()
358+
)
359+
)
360+
or
361+
exists(AbsentModuleObjectInternal mod |
362+
PointsToInternal::pointsTo(imp.(ImportMemberNode).getModule(name), ctx, mod, _) and
363+
common_module_name(mod.getName() + "." + name)
364+
)
365+
}
366+
367+
predicate common_module_name(string name) {
368+
name = "zope.interface"
369+
or
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name = "six.moves"
371+
}
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330373
library class ClassDecl extends @py_object {
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332375
ClassDecl() {

‎python/ql/src/semmle/python/pointsto/PointsTo.qll‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -130,7 +130,7 @@ module PointsTo {
130130
PointsToInternal::pointsTo(f, context, value, origin) and
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cls = value.getClass().getSource() |
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obj = value.getSource() or
133-
not exists(value.getSource()) and obj = origin
133+
not exists(value.getSource()) and not value.isMissing() and obj = origin
134134
)
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or
136136
/* Backwards compatibility for *args and **kwargs */

‎python/ql/src/semmle/python/security/Exceptions.qll‎

Lines changed: 2 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -7,12 +7,8 @@ import python
77
import semmle.python.security.TaintTracking
88
import semmle.python.security.strings.Basic
99

10-
private ModuleObject theTracebackModule() {
11-
result.getName() = "traceback"
12-
}
13-
14-
private FunctionObject traceback_function(string name) {
15-
result = theTracebackModule().attr(name)
10+
private Value traceback_function(string name) {
11+
result = Module::named("traceback").attr(name)
1612
}
1713

1814
/**

‎python/ql/test/library-tests/PointsTo/absent/Absent.expected‎

Lines changed: 7 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,7 @@
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| absent.py:3:8:3:11 | ControlFlowNode for ImportExpr | Missing module xxxx |
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| absent.py:4:1:4:4 | ControlFlowNode for xxxx | Missing module xxxx |
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| absent.py:6:6:6:9 | ControlFlowNode for ImportExpr | Missing module xxxx |
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| absent.py:6:18:6:21 | ControlFlowNode for ImportMember | Missing module attribute xxxx.open |
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| absent.py:8:1:8:4 | ControlFlowNode for open | Missing module attribute xxxx.open |
6+
| absent.py:12:8:12:13 | ControlFlowNode for ImportExpr | Module module |
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| absent.py:14:1:14:6 | ControlFlowNode for module | Module module |

‎python/ql/test/library-tests/PointsTo/absent/Absent.ql‎

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,9 @@
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import python
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import semmle.python.objects.Modules
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5+
from Value val, ControlFlowNode f
6+
where //val = Value::named(name) and
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f.pointsTo(val)
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select f, val
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‎python/ql/test/library-tests/PointsTo/absent/absent.py‎

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,14 @@
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#There is no xxxx, rely on AbsentModule
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import xxxx
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xxxx
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from xxxx import open
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open()
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#This is be present, so shouldn't be missing
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import module
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module

‎python/ql/test/library-tests/PointsTo/absent/module.py‎

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