Skip to content

Java: replace the dead String.valueOf(CharSequence) summary with a synthetic callable #22315

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Draft
Copilot wants to merge 4 commits into
base: main
Choose a base branch
from
Draft

Java: replace the dead String.valueOf(CharSequence) summary with a synthetic callable #22315

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
d3775a2
Initial plan
Copilot Aug 11, 2026
925d3e2
Java: replace non-existent String.valueOf(CharSequence) summary with …
Copilot Aug 11, 2026
c601c6c
Simplify test method signature
Copilot Aug 11, 2026
7e3c144
Java: Update test expectations
hvitved Aug 11, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 4 additions & 0 deletions java/ql/lib/change-notes/2026-08-11-string-valueof-charsequence.md
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,4 @@
---
category: minorAnalysis
---
* Removed the summary model for `String.valueOf(CharSequence)`, which does not exist. Instead, taint is now propagated through calls to `String.valueOf(Object)` when the argument is a `CharSequence`, for example a `String` or a `StringBuilder`.
1 change: 0 additions & 1 deletion java/ql/lib/ext/java.lang.model.yml
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -134,7 +134,6 @@ extensions:
- ["java.lang", "String", False, "valueOf", "(char)", "", "Argument[0]", "ReturnValue", "taint", "manual"]
- ["java.lang", "String", False, "valueOf", "(char[])", "", "Argument[0]", "ReturnValue", "taint", "manual"]
- ["java.lang", "String", False, "valueOf", "(char[],int,int)", "", "Argument[0]", "ReturnValue", "taint", "manual"]
- ["java.lang", "String", False, "valueOf", "(CharSequence)", "", "Argument[0]", "ReturnValue", "taint", "manual"]
- ["java.lang", "StringBuffer", True, "StringBuffer", "(CharSequence)", "", "Argument[0]", "Argument[this]", "taint", "manual"]
- ["java.lang", "StringBuffer", True, "StringBuffer", "(String)", "", "Argument[0]", "Argument[this]", "taint", "manual"]
- ["java.lang", "StringBuilder", True, "StringBuilder", "", "", "Argument[0]", "Argument[this]", "taint", "manual"]
Expand Down
1 change: 1 addition & 0 deletions java/ql/lib/semmle/code/java/dataflow/FlowSummary.qll
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -44,6 +44,7 @@ private module SyntheticCallables {
private import semmle.code.java.dispatch.WrappedInvocation
private import semmle.code.java.frameworks.android.Intent
private import semmle.code.java.frameworks.Stream
private import semmle.code.java.frameworks.Strings
}

private newtype TSummarizedCallableBase =
Expand Down
40 changes: 40 additions & 0 deletions java/ql/lib/semmle/code/java/frameworks/Strings.qll
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,40 @@
/** Definitions related to `java.lang.String`. */
overlay[local?]
module;

private import java
private import semmle.code.java.dataflow.FlowSummary

/**
* A call to `String.valueOf(Object)` where the argument is a `CharSequence`,
* for example a `String` or a `StringBuilder`.
*
* Such a call is equivalent to calling `toString()` on the argument, which for
* a `CharSequence` is guaranteed to yield a string containing the characters of
* the argument, so taint is propagated. This is in contrast to `valueOf(Object)`
* calls in general, where `toString()` may not expose the state of the argument.
*/
private class StringValueOfCharSequence extends SyntheticCallable {
StringValueOfCharSequence() { this = "java.lang.String.valueOf(Object)+CharSequence" }

override MethodCall getACall() {
exists(Method m | m = result.getMethod().getSourceDeclaration() |
m.hasQualifiedName("java.lang", "String", "valueOf") and
m.getParameterType(0) instanceof TypeObject
) and
result
.getArgument(0)
.getType()
.(RefType)
.getAnAncestor()
.hasQualifiedName("java.lang", "CharSequence")
}

override predicate propagatesFlow(string input, string output, boolean preservesValue) {
input = "Argument[0]" and
output = "ReturnValue" and
preservesValue = false
}

override Type getReturnType() { result instanceof TypeString }
}
26 changes: 26 additions & 0 deletions java/ql/test/library-tests/dataflow/string-valueof/A.java
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,26 @@
public class A {
String source() { return "source"; }

void sink(Object o) {}

void m() {
String s = source();

sink(String.valueOf(s)); // $ hasTaintFlow

CharSequence seq = s;
sink(String.valueOf(seq)); // $ hasTaintFlow

StringBuilder sb = new StringBuilder(s);
sink(String.valueOf(sb)); // $ hasTaintFlow

sink(String.valueOf(s.toCharArray())); // $ hasTaintFlow

sink(String.valueOf(s.charAt(0))); // $ hasTaintFlow

// `toString` on an arbitrary object is not assumed to expose the state of
// the object, so no flow is expected here.
Object o = s;
sink(String.valueOf(o));
}
}
39 changes: 39 additions & 0 deletions java/ql/test/library-tests/dataflow/string-valueof/test.expected
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,39 @@
models
| 1 | Summary: java.lang; CharSequence; true; charAt; ; ; Argument[this]; ReturnValue; taint; manual |
| 2 | Summary: java.lang; String; false; toCharArray; ; ; Argument[this]; ReturnValue; taint; manual |
| 3 | Summary: java.lang; String; false; valueOf; (char); ; Argument[0]; ReturnValue; taint; manual |
| 4 | Summary: java.lang; String; false; valueOf; (char[]); ; Argument[0]; ReturnValue; taint; manual |
| 5 | Summary: java.lang; StringBuilder; true; StringBuilder; ; ; Argument[0]; Argument[this]; taint; manual |
edges
| A.java:7:16:7:23 | source(...) : String | A.java:9:25:9:25 | s : String | provenance | |
| A.java:7:16:7:23 | source(...) : String | A.java:12:25:12:27 | seq : String | provenance | |
| A.java:7:16:7:23 | source(...) : String | A.java:14:42:14:42 | s : String | provenance | |
| A.java:7:16:7:23 | source(...) : String | A.java:17:25:17:25 | s : String | provenance | |
| A.java:7:16:7:23 | source(...) : String | A.java:19:25:19:25 | s : String | provenance | |
| A.java:9:25:9:25 | s : String | A.java:9:10:9:26 | valueOf(...) | provenance | java.lang.String.valueOf(Object)+CharSequence |
| A.java:12:25:12:27 | seq : String | A.java:12:10:12:28 | valueOf(...) | provenance | java.lang.String.valueOf(Object)+CharSequence |
| A.java:14:24:14:43 | new StringBuilder(...) : StringBuilder | A.java:15:25:15:26 | sb : StringBuilder | provenance | |
| A.java:14:42:14:42 | s : String | A.java:14:24:14:43 | new StringBuilder(...) : StringBuilder | provenance | MaD:5 |
| A.java:15:25:15:26 | sb : StringBuilder | A.java:15:10:15:27 | valueOf(...) | provenance | java.lang.String.valueOf(Object)+CharSequence |
| A.java:17:25:17:25 | s : String | A.java:17:25:17:39 | toCharArray(...) : char[] | provenance | MaD:2 |
| A.java:17:25:17:39 | toCharArray(...) : char[] | A.java:17:10:17:40 | valueOf(...) | provenance | MaD:4 |
| A.java:19:25:19:25 | s : String | A.java:19:25:19:35 | charAt(...) : Number | provenance | MaD:1 |
| A.java:19:25:19:35 | charAt(...) : Number | A.java:19:10:19:36 | valueOf(...) | provenance | MaD:3 |
nodes
| A.java:7:16:7:23 | source(...) : String | semmle.label | source(...) : String |
| A.java:9:10:9:26 | valueOf(...) | semmle.label | valueOf(...) |
| A.java:9:25:9:25 | s : String | semmle.label | s : String |
| A.java:12:10:12:28 | valueOf(...) | semmle.label | valueOf(...) |
| A.java:12:25:12:27 | seq : String | semmle.label | seq : String |
| A.java:14:24:14:43 | new StringBuilder(...) : StringBuilder | semmle.label | new StringBuilder(...) : StringBuilder |
| A.java:14:42:14:42 | s : String | semmle.label | s : String |
| A.java:15:10:15:27 | valueOf(...) | semmle.label | valueOf(...) |
| A.java:15:25:15:26 | sb : StringBuilder | semmle.label | sb : StringBuilder |
| A.java:17:10:17:40 | valueOf(...) | semmle.label | valueOf(...) |
| A.java:17:25:17:25 | s : String | semmle.label | s : String |
| A.java:17:25:17:39 | toCharArray(...) : char[] | semmle.label | toCharArray(...) : char[] |
| A.java:19:10:19:36 | valueOf(...) | semmle.label | valueOf(...) |
| A.java:19:25:19:25 | s : String | semmle.label | s : String |
| A.java:19:25:19:35 | charAt(...) : Number | semmle.label | charAt(...) : Number |
subpaths
testFailures
3 changes: 3 additions & 0 deletions java/ql/test/library-tests/dataflow/string-valueof/test.ql
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,3 @@
import utils.test.InlineFlowTest
import DefaultFlowTest
import TaintFlow::PathGraph
2 changes: 2 additions & 0 deletions java/ql/test/utils/modelgenerator/dataflow/p/Joiner.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -82,6 +82,7 @@ public String toString() {
}

// heuristic-summary=p;Joiner;false;add;(CharSequence);;Argument[this];ReturnValue;value;df-generated
// heuristic-summary=p;Joiner;false;add;(CharSequence);;Argument[0];Argument[this];taint;df-generated
// contentbased-summary=p;Joiner;false;add;(CharSequence);;Argument[this];ReturnValue;value;dfc-generated
// MISSING content based summaries for "elts". This could be a synthetic field.
public Joiner add(CharSequence newElement) {
Expand All @@ -107,6 +108,7 @@ private int checkAddLength(int oldLen, int inc) {
}

// heuristic-summary=p;Joiner;false;merge;(Joiner);;Argument[this];ReturnValue;value;df-generated
// heuristic-summary=p;Joiner;false;merge;(Joiner);;Argument[0];Argument[this];taint;df-generated
// contentbased-summary=p;Joiner;false;merge;(Joiner);;Argument[this];ReturnValue;value;dfc-generated
// MISSING content based summaries for "elts". This could be a synthetic field.
public Joiner merge(Joiner other) {
Expand Down
Loading