Fix the absolute path of the main script after chdir

* Fixes #2709

Author: eregon

CHANGELOG.md

@@ -29,6 +29,7 @@ Compatibility:
 * Fix `Kernel#sprintf` formatting for `%c` when used non-ASCII encoding (#2369, @andrykonchin).
 * Fix `Kernel#sprintf` argument casting for `%c` (@andrykonchin).
 * Implement the `rb_enc_strlen` function for use by native extensions (@nirvdrum).
+* Fix the absolute path of the main script after chdir (#2709, @eregon).
 
 Performance:
 

src/main/java/org/truffleruby/core/kernel/KernelNodes.java

@@ -22,6 +22,7 @@
 import com.oracle.truffle.api.interop.InteropLibrary;
 import com.oracle.truffle.api.interop.UnsupportedMessageException;
 import com.oracle.truffle.api.object.PropertyGetter;
+import com.oracle.truffle.api.source.Source;
 import com.oracle.truffle.api.strings.AbstractTruffleString;
 import com.oracle.truffle.api.strings.TruffleString;
 import com.oracle.truffle.api.utilities.AssumedValue;
@@ -300,9 +301,9 @@ protected RubyString getCallerPath(Object feature,
                             coreExceptions().loadError("cannot infer basepath", featureString, this));
                 }
 
-                String sourcePath = getLanguage().getSourcePath(sourceSection.getSource());
-
-                sourcePath = getContext().getFeatureLoader().canonicalize(sourcePath);
+                Source source = sourceSection.getSource();
+                String sourcePath = getLanguage().getSourcePath(source);
+                sourcePath = getContext().getFeatureLoader().canonicalize(sourcePath, source);
 
                 featurePath = getContext().getFeatureLoader().dirname(sourcePath) + "/" + featureString;
             }
@@ -394,7 +395,7 @@ protected RubyString canonicalPath(Object string,
                 @Cached TruffleString.FromJavaStringNode fromJavaStringNode) {
             final String expandedPath = getContext()
                     .getFeatureLoader()
-                    .canonicalize(RubyGuards.getJavaString(string));
+                    .canonicalize(RubyGuards.getJavaString(string), null);
             return createString(fromJavaStringNode, expandedPath, Encodings.UTF_8);
         }
 

src/main/java/org/truffleruby/core/thread/ThreadBacktraceLocationNodes.java

@@ -66,7 +66,7 @@ public static Object getAbsolutePath(SourceSection sourceSection, RubyBaseNode n
                     return nil;
                 } else if (source.getPath() != null) { // A normal file
                     final String path = language.getSourcePath(source);
-                    final String canonicalPath = context.getFeatureLoader().canonicalize(path);
+                    final String canonicalPath = context.getFeatureLoader().canonicalize(path, source);
                     var cachedRope = language.tstringCache.getTString(TStringUtils.utf8TString(canonicalPath),
                             Encodings.UTF_8);
                     return node.createString(cachedRope, Encodings.UTF_8);

src/main/java/org/truffleruby/language/loader/FeatureLoader.java

@@ -64,6 +64,9 @@
 
 public class FeatureLoader {
 
+    private static final int PATH_MAX = 1024; // jnr-posix hard codes this value
+    private static final String[] EXTENSIONS = new String[]{ TruffleRuby.EXTENSION, RubyLanguage.CEXT_EXTENSION };
+
     private final RubyContext context;
     private final RubyLanguage language;
 
@@ -80,9 +83,9 @@ public class FeatureLoader {
 
     private String cwd = null;
     private Object getcwd;
-    private static final int PATH_MAX = 1024; // jnr-posix hard codes this value
 
-    private static final String[] EXTENSIONS = new String[]{ TruffleRuby.EXTENSION, RubyLanguage.CEXT_EXTENSION };
+    private Source mainScriptSource;
+    private String mainScriptAbsolutePath;
 
     public FeatureLoader(RubyContext context, RubyLanguage language) {
         this.context = context;
@@ -95,6 +98,13 @@ public void initialize(NativeConfiguration nativeConfiguration, TruffleNFIPlatfo
         }
     }
 
+    public void setMainScript(Source source, String absolutePath) {
+        assert mainScriptSource == null;
+        assert mainScriptAbsolutePath == null;
+        mainScriptSource = source;
+        mainScriptAbsolutePath = absolutePath;
+    }
+
     public void addAutoload(RubyConstant autoloadConstant) {
         final String autoloadPath = autoloadConstant.getAutoloadConstant().getAutoloadPath();
         final String basename = basenameWithoutExtension(autoloadPath);
@@ -229,7 +239,13 @@ private String makeAbsolute(String path) {
         }
     }
 
-    public String canonicalize(String path) {
+    public String canonicalize(String path, Source source) {
+        // Special case for the main script which has a relative Source#getPath():
+        // We need to resolve it correctly, even if the CWD changed since then.
+        if (source != null && source.equals(mainScriptSource)) {
+            return mainScriptAbsolutePath;
+        }
+
         // First, make the path absolute, by expanding relative to the context CWD
         // Otherwise, getCanonicalPath() uses user.dir as CWD which is incorrect.
         final String absolutePath = makeAbsolute(path);

src/main/java/org/truffleruby/language/loader/MainLoader.java

@@ -100,6 +100,8 @@ public RubySource loadFromFile(Env env, Node currentNode, String mainPath) throw
 
         final Source mainSource = fileLoader.buildSource(file, mainPath, sourceTString, false, true);
 
+        context.getFeatureLoader().setMainScript(mainSource, file.getCanonicalFile().getPath());
+
         return new RubySource(mainSource, mainPath, sourceTString);
     }