Report crash on package without pub get

[glesica]

The visitor barfs if an export uses a package: style URI rather than a relative path. Seems like it might be an analyzer bug (it may have something to do with dart-lang/sdk#35174), but noting it here for the future. Example stack trace:

 dcdg --exported-only
file:///home/george/w_common/lib/disposable.dart
{DisposableManager, DisposableManagerV2, DisposableManagerV3, DisposableManagerV4, DisposableManagerV5, DisposableManagerV6, DisposableManagerV7, ObjectDisposedException}
Unhandled exception:
NoSuchMethodError: The method 'accept' was called on null.
Receiver: null
Tried calling: accept<void>(Instance of 'ClassElementCollector')
#0      Object.noSuchMethod (dart:core/runtime/libobject_patch.dart:50:5)
#1      ClassElementCollector.visitExportElement (package:dcdg/src/class_element_collector.dart:47:29)
#2      ExportElementImpl.accept (package:analyzer/src/dart/element/element.dart:4668:53)
#3      ElementImpl.safelyVisitChildren (package:analyzer/src/dart/element/element.dart:3616:15)
#4      LibraryElementImpl.visitChildren (package:analyzer/src/dart/element/element.dart:6604:5)
#5      RecursiveElementVisitor.visitLibraryElement (package:analyzer/dart/element/visitor.dart:265:13)
#6      LibraryElementImpl.accept (package:analyzer/src/dart/element/element.dart:6488:53)
#7      findClassElements (package:dcdg/src/find_class_elements.dart:49:33)
<asynchronous suspension>
#8      main (file:///home/george/dcdg.dart/bin/dcdg.dart:28:25)
<asynchronous suspension>
#9      _startIsolate.<anonymous closure> (dart:isolate/runtime/libisolate_patch.dart:298:32)
#10     _RawReceivePortImpl._handleMessage (dart:isolate/runtime/libisolate_patch.dart:171:12)

[glesica]

Turns out I'd just forgotten to pub get in the package I was running against. So this isn't a bug, but it might be nice to catch this and suggest running pub get since that seems like a likely thing to be forgotten now and again.

[Nicolaidam]

Hi, So i just got the same error. What do you mean with "Turns out I'd just forgotten to pub get in the package I was running against."?
I've tried running flutter pub get dcdg and afterwards flutter pub run dcdg and i still get the error.
I use visual studio btw.

[glesica]

You don't need to add DCDG as a dependency of your project, it just needs to be installed somehow (usually pub global activate dcdg). But the package you want to run it against needs to have its dependencies fetched. So if you have a package called foo that you want a class diagram for, you need to have run pub get (or flutter pub get if you're using Flutter) in the foo package before you run DCDG.

[Nicolaidam]

Thanks for the fast answer!

1. So the first thing i do is installing DCDG with the command flutter pub global activate dcdg (since i use flutter) in the main folder of my project.
   
2. I want to make a class diagram of my Main.dart file, so I move to the "lib" folder and executes the command flutter pub get.
   
3. I run the command pub global run dcdg in the Lib folder and getting following result:
   

So it seems the pack is not installed correctly.. I'm sorry if I do a stupid mistake, im pretty new with Flutter so please bear with me. Hope you can help me, and have a great day!

[glesica]

You run DCDG from the root of your project (where your pubspec.yaml is). It runs against a Dart package, not an individual file.

[Nicolaidam]

Okay, but when I run "flutter pub global run dcdg" from the main folder I get this error:

Nicolais-MacBook-Pro:acdc_flutter_app nicolai$ flutter pub global activate dcdg
Package dcdg is currently active at version 2.0.1.
Resolving dependencies...

• analyzer 0.36.4 (1.1.0 available)

• args 1.6.0 (2.0.0 available)

• async 2.4.2 (2.5.0 available)

• charcode 1.1.3 (1.2.0 available)

• collection 1.14.13 (1.15.0 available)

• convert 2.1.1 (3.0.0 available)

• crypto 2.1.5 (3.0.0 available)

• csslib 0.16.2 (0.17.0 available)

• dcdg 2.0.1

• file 5.2.1 (6.1.0 available)

• front_end 0.1.19 (0.1.29 available)

• glob 1.2.0 (2.0.0 available)

• html 0.14.0+4 (0.15.0 available)

• intl 0.16.1 (0.17.0 available)

• js 0.6.2 (0.6.3 available)

• kernel 0.3.19 (0.3.29 available)

• meta 1.2.4 (1.3.0 available)

• node_interop 1.2.1

• node_io 1.2.0

• package_config 1.9.3 (2.0.0 available)

• path 1.7.0 (1.8.0 available)

• pedantic 1.9.2 (1.11.0 available)

• pub_semver 1.4.4 (2.0.0 available)

• source_span 1.7.0 (1.8.1 available)

• string_scanner 1.0.5 (1.1.0 available)

• term_glyph 1.1.0 (1.2.0 available)

• typed_data 1.2.0 (1.3.0 available)

• watcher 0.9.7+15 (1.0.0 available)

• yaml 2.2.1 (3.1.0 available)
  Precompiling executables...
  Precompiled dcdg:dcdg.
  Installed executable dcdg.
  Warning: Pub installs executables into $HOME/Documents/flutter/.pub-cache/bin, which is not on your path.
  You can fix that by adding this to your shell's config file (.bashrc, .bash_profile, etc.):

  export PATH="$PATH":"$HOME/Documents/flutter/.pub-cache/bin"

Activated dcdg 2.0.1.
Nicolais-MacBook-Pro:acdc_flutter_app nicolai$ flutter pub get
Running "flutter pub get" in acdc_flutter_app... 0,5s
Nicolais-MacBook-Pro:acdc_flutter_app nicolai$ flutter pub global run dcdg
Unhandled exception:
NoSuchMethodError: The method 'accept' was called on null.
Receiver: null
Tried calling: accept(Instance of 'ConstantVisitor')
#0 Object.noSuchMethod (dart:core-patch/object_patch.dart:51:5)
#1 ConstantEvaluationEngine.evaluateConstructorCall (package:analyzer/src/dart/constant/evaluation.dart:717:53)
#2 ConstantVerifier.visitInstanceCreationExpression (package:analyzer/src/dart/constant/constant_verifier.dart:131:27)
#3 InstanceCreationExpressionImpl.accept (package:analyzer/src/dart/ast/ast.dart:6111:15)
#4 NodeListImpl.accept (package:analyzer/src/dart/ast/ast.dart:7687:20)
#5 ListLiteralImpl.visitChildren (package:analyzer/src/dart/ast/ast.dart:6842:15)
#6 RecursiveAstVisitor.visitListLiteral (package:analyzer/dart/ast/visitor.dart:1045:10)
#7 ConstantVerifier.visitListLiteral (package:analyzer/src/dart/constant/constant_verifier.dart:145:11)
#8 ListLiteralImpl.accept (package:analyzer/src/dart/ast/ast.dart:6837:49)
#9 NamedExpressionImpl.visitChildren (package:analyzer/src/dart/ast/ast.dart:7446:18)
#10 RecursiveAstVisitor.visitNamedExpression (package:analyzer/dart/ast/visitor.dart:1075:10)
#11 NamedExpressionImpl.accept (package:analyzer/src/dart/ast/ast.dart:7441:49)
#12 NodeListImpl.accept (package:analyzer/src/dart/ast/ast.dart:7687:20)
#13 ArgumentListImpl.visitChildren (package:analyzer/src/dart/ast/ast.dart:378:16)
#14 RecursiveAstVisitor.visitArgumentList (package:analyzer/dart/ast/visitor.dart:625:10)
#15 ArgumentListImpl.accept (package:analyzer/src/dart/ast/ast.dart:374:49)
#16 InstanceCreationExpressionImpl.visitChildren (package:analyzer/src/dart/ast/ast.dart:6199:20)
#17 RecursiveAstVisitor.visitInstanceCreationExpression (package:analyzer/dart/ast/visitor.dart:991:10)
#18 ConstantVerifier.visitInstanceCreationExpression (package:analyzer/src/dart/constant/constant_verifier.dart:139:13)
#19 InstanceCreationExpressionImpl.accept (package:analyzer/src/dart/ast/ast.dart:6111:15)
#20 NamedExpressionImpl.visitChildren (package:analyzer/src/dart/ast/ast.dart:7446:18)
#21 RecursiveAstVisitor.visitNamedExpression (package:analyzer/dart/ast/visitor.dart:1075:10)
#22 NamedExpressionImpl.accept (package:analyzer/src/dart/ast/ast.dart:7441:49)
#23 NodeListImpl.accept (package:analyzer/src/dart/ast/ast.dart:7687:20)
#24 ArgumentListImpl.visitChildren (package:analyzer/src/dart/ast/ast.dart:378:16)
#25 RecursiveAstVisitor.visitArgumentList (package:analyzer/dart/ast/visitor.dart:625:10)
#26 ArgumentListImpl.accept (package:analyzer/src/dart/ast/ast.dart:374:49)
#27 InstanceCreationExpressionImpl.visitChildren (package:analyzer/src/dart/ast/ast.dart:6199:20)
#28 RecursiveAstVisitor.visitInstanceCreationExpression (package:analyzer/dart/ast/visitor.dart:991:10)
#29 ConstantVerifier.visitInstanceCreationExpression (package:analyzer/src/dart/constant/constant_verifier.dart:139:13)
#30 InstanceCreationExpressionImpl.accept (package:analyzer/src/dart/ast/ast.dart:6111:15)
#31 NodeListImpl.accept (package:analyzer/src/dart/ast/ast.dart:7687:20)
#32 ListLiteralImpl.visitChildren (package:analyzer/src/dart/ast/ast.dart:6842:15)
#33 RecursiveAstVisitor.visitListLiteral (package:analyzer/dart/ast/visitor.dart:1045:10)
#34 ConstantVerifier.visitListLiteral (package:analyzer/src/dart/constant/constant_verifier.dart:145:11)
#35 ListLiteralImpl.accept (package:analyzer/src/dart/ast/ast.dart:6837:49)
#36 NamedExpressionImpl.visitChildren (package:analyzer/src/dart/ast/ast.dart:7446:18)
#37 RecursiveAstVisitor.visitNamedExpression (package:analyzer/dart/ast/visitor.dart:1075:10)
#38 NamedExpressionImpl.accept (package:analyzer/src/dart/ast/ast.dart:7441:49)
#39 NodeListImpl.accept (package:analyzer/src/dart/ast/ast.dart:7687:20)
#40 ArgumentListImpl.visitChildren (package:analyzer/src/dart/ast/ast.dart:378:16)
#41 RecursiveAstVisitor.visitArgumentList (package:analyzer/dart/ast/visitor.dart:625:10)
#42 ArgumentListImpl.accept (package:analyzer/src/dart/ast/ast.dart:374:49)
#43 InstanceCreationExpressionImpl.visitChildren (package:analyzer/src/dart/ast/ast.dart:6199:20)
#44 RecursiveAstVisitor.visitInstanceCreationExpression (package:analyzer/dart/ast/visitor.dart:991:10)
#45 ConstantVerifier.visitInstanceCreationExpression (package:analyzer/src/dart/constant/constant_verifier.dart:139:13)
#46 InstanceCreationExpressionImpl.accept (package:analyzer/src/dart/ast/ast.dart:6111:15)
#47 ReturnStatementImpl.visitChildren (package:analyzer/src/dart/ast/ast.dart:8655:18)
#48 RecursiveAstVisitor.visitReturnStatement (package:analyzer/dart/ast/visitor.dart:1160:10)
#49 ReturnStatementImpl.accept (package:analyzer/src/dart/ast/ast.dart:8651:49)
#50 NodeListImpl.accept (package:analyzer/src/dart/ast/ast.dart:7687:20)
#51 BlockImpl.visitChildren (package:analyzer/src/dart/ast/ast.dart:1121:17)
#52 RecursiveAstVisitor.visitBlock (package:analyzer/dart/ast/visitor.dart:667:10)
#53 BlockImpl.accept (package:analyzer/src/dart/ast/ast.dart:1117:49)
#54 IfStatementImpl.visitChildren (package:analyzer/src/dart/ast/ast.dart:5704:21)
#55 RecursiveAstVisitor.visitIfStatement (package:analyzer/dart/ast/visitor.dart:967:10)
#56 IfStatementImpl.accept (package:analyzer/src/dart/ast/ast.dart:5699:49)
#57 NodeListImpl.accept (package:analyzer/src/dart/ast/ast.dart:7687:20)
#58 BlockImpl.visitChildren (package:analyzer/src/dart/ast/ast.dart:1121:17)
#59 RecursiveAstVisitor.visitBlock (package:analyzer/dart/ast/visitor.dart:667:10)
#60 BlockImpl.accept (package:analyzer/src/dart/ast/ast.dart:1117:49)
#61 BlockFunctionBodyImpl.visitChildren (package:analyzer/src/dart/ast/ast.dart:1076:13)
#62 RecursiveAstVisitor.visitBlockFunctionBody (package:analyzer/dart/ast/visitor.dart:673:10)
#63 BlockFunctionBodyImpl.accept (package:analyzer/src/dart/ast/ast.dart:1072:49)
#64 FunctionExpressionImpl.visitChildren (package:analyzer/src/dart/ast/ast.dart:5016:12)
#65 RecursiveAstVisitor.visitFunctionExpression (package:analyzer/dart/ast/visitor.dart:919:10)
#66 ConstantVerifier.visitFunctionExpression (package:analyzer/src/dart/constant/constant_verifier.dart:115:11)
#67 FunctionExpressionImpl.accept (package:analyzer/src/dart/ast/ast.dart:5010:49)
#68 FunctionDeclarationImpl.visitChildren (package:analyzer/src/dart/ast/ast.dart:4869:26)
#69 RecursiveAstVisitor.visitFunctionDeclaration (package:analyzer/dart/ast/visitor.dart:907:10)
#70 FunctionDeclarationImpl.accept (package:analyzer/src/dart/ast/ast.dart:4862:49)
#71 FunctionDeclarationStatementImpl.visitChildren (package:analyzer/src/dart/ast/ast.dart:4910:27)
#72 RecursiveAstVisitor.visitFunctionDeclarationStatement (package:analyzer/dart/ast/visitor.dart:913:10)
#73 FunctionDeclarationStatementImpl.accept (package:analyzer/src/dart/ast/ast.dart:4906:15)
#74 NodeListImpl.accept (package:analyzer/src/dart/ast/ast.dart:7687:20)
#75 BlockImpl.visitChildren (package:analyzer/src/dart/ast/ast.dart:1121:17)
#76 RecursiveAstVisitor.visitBlock (package:analyzer/dart/ast/visitor.dart:667:10)
#77 BlockImpl.accept (package:analyzer/src/dart/ast/ast.dart:1117:49)
#78 BlockFunctionBodyImpl.visitChildren (package:analyzer/src/dart/ast/ast.dart:1076:13)
#79 RecursiveAstVisitor.visitBlockFunctionBody (package:analyzer/dart/ast/visitor.dart:673:10)
#80 BlockFunctionBodyImpl.accept (package:analyzer/src/dart/ast/ast.dart:1072:49)
#81 MethodDeclarationImpl.visitChildren (package:analyzer/src/dart/ast/ast.dart:7127:12)
#82 RecursiveAstVisitor.visitMethodDeclaration (package:analyzer/dart/ast/visitor.dart:1057:10)
#83 ConstantVerifier.visitMethodDeclaration (package:analyzer/src/dart/constant/constant_verifier.dart:163:11)
#84 MethodDeclarationImpl.accept (package:analyzer/src/dart/ast/ast.dart:7118:49)
#85 NodeListImpl.accept (package:analyzer/src/dart/ast/ast.dart:7687:20)
#86 ClassDeclarationImpl.visitChildren (package:analyzer/src/dart/ast/ast.dart:1590:13)
#87 RecursiveAstVisitor.visitClassDeclaration (package:analyzer/dart/ast/visitor.dart:703:10)
#88 ClassDeclarationImpl.accept (package:analyzer/src/dart/ast/ast.dart:1560:49)
#89 NodeListImpl.accept (package:analyzer/src/dart/ast/ast.dart:7687:20)
#90 CompilationUnitImpl.visitChildren (package:analyzer/src/dart/ast/ast.dart:2167:21)
#91 RecursiveAstVisitor.visitCompilationUnit (package:analyzer/dart/ast/visitor.dart:727:10)
#92 CompilationUnitImpl.accept (package:analyzer/src/dart/ast/ast.dart:2146:49)
#93 LibraryAnalyzer._computeConstantErrors (package:analyzer/src/dart/analysis/library_analyzer.dart:246:10)
#94 LibraryAnalyzer._computeVerifyErrors (package:analyzer/src/dart/analysis/library_analyzer.dart:402:5)
#95 LibraryAnalyzer.analyzeSync.. (package:analyzer/src/dart/analysis/library_analyzer.dart:172:9)
#96 _LinkedHashMapMixin.forEach (dart:collection-patch/compact_hash.dart:377:8)
#97 LibraryAnalyzer.analyzeSync. (package:analyzer/src/dart/analysis/library_analyzer.dart:171:13)
#98 _PerformanceTagImpl.makeCurrentWhile (package:analyzer/src/generated/utilities_general.dart:258:15)
#99 LibraryAnalyzer.analyzeSync (package:analyzer/src/dart/analysis/library_analyzer.dart:170:34)
#100 LibraryAnalyzer.analyze. (package:analyzer/src/dart/analysis/library_analyzer.dart:111:14)
#101 _PerformanceTagImpl.makeCurrentWhile (package:analyzer/src/generated/utilities_general.dart:258:15)
#102 LibraryAnalyzer.analyze (package:analyzer/src/dart/analysis/library_analyzer.dart:110:43)
#103 AnalysisDriver._computeAnalysisResult. (package:analyzer/src/dart/analysis/driver.dart:1451:63)
#104 PerformanceLog.run (package:analyzer/src/dart/analysis/performance_logger.dart:34:15)
#105 AnalysisDriver._computeAnalysisResult (package:analyzer/src/dart/analysis/driver.dart:1428:20)
#106 AnalysisDriver.performWork (package:analyzer/src/dart/analysis/driver.dart:1100:33)

#107 AnalysisDriverScheduler._run (package:analyzer/src/dart/analysis/driver.dart:2188:24)

#108 AnalysisDriverScheduler.start (package:analyzer/src/dart/analysis/driver.dart:2118:5)
#109 ContextBuilderImpl.createContext (package:analyzer/src/dart/analysis/context_builder.dart:77:17)
#110 new AnalysisContextCollectionImpl (package:analyzer/src/dart/analysis/analysis_context_collection.dart:46:36)
#111 findClassElements (package:dcdg/src/find_class_elements.dart:26:29)
#112 main (file:///Users/nicolai/Documents/flutter/.pub-cache/hosted/pub.dartlang.org/dcdg-2.0.1/bin/dcdg.dart:28:25)
#113 _startIsolate. (dart:isolate-patch/isolate_patch.dart:299:32)
#114 _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:168:12)

#0 AnalysisDriver._computeAnalysisResult. (package:analyzer/src/dart/analysis/driver.dart:1487:9)
#1 PerformanceLog.run (package:analyzer/src/dart/analysis/performance_logger.dart:34:15)
#2 AnalysisDriver._computeAnalysisResult (package:analyzer/src/dart/analysis/driver.dart:1428:20)
#3 AnalysisDriver.performWork (package:analyzer/src/dart/analysis/driver.dart:1100:33)

#4 AnalysisDriverScheduler._run (package:analyzer/src/dart/analysis/driver.dart:2188:24)

#5 AnalysisDriverScheduler.start (package:analyzer/src/dart/analysis/driver.dart:2118:5)
#6 ContextBuilderImpl.createContext (package:analyzer/src/dart/analysis/context_builder.dart:77:17)
#7 new AnalysisContextCollectionImpl (package:analyzer/src/dart/analysis/analysis_context_collection.dart:46:36)
#8 findClassElements (package:dcdg/src/find_class_elements.dart:26:29)
#9 main (file:///Users/nicolai/Documents/flutter/.pub-cache/hosted/pub.dartlang.org/dcdg-2.0.1/bin/dcdg.dart:28:25)
#10 _startIsolate. (dart:isolate-patch/isolate_patch.dart:299:32)
#11 _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:168:12)
pub finished with exit code 255

[glesica]

OK, so that's the error that I saw above. For me, the fix was to run pub get (so you probably want to run flutter pub get) in the package I wanted to run DCDG against before running it. This is so that the analyzer can find your package's dependencies and parse them.

[Nicolaidam]

Thank for your quick reply.

It doesnt work for me even though I run flutter pub get in the pack.
I get the following:
Nicolais-MacBook-Pro:models nicolai$ flutter pub global run dcdg
Error: No Dart package found at .
pub finished with exit code 1

Can there be something wrong with the terminal i use? I just use the build in terminal in VS.
Do you use Android Studio when you generate the diagrams with Flutter?

I've followed this video and done exactly the same, but i cant run: flutter pub global run dcdg
https://www.youtube.com/watch?v=vDzo3rz2r5M&ab_channel=LearnWithFun

[glesica]

Are you running it in the same directory as your Dart package? You have to point it at the directory that contains your pubspec.yaml.

[glesica]

Closing because the original problem should no longer be an issue with the latest release.

[Nicolaidam]

Are you running it in the same directory as your Dart package? You have to point it at the directory that contains your pubspec.yaml.

yes I run it from lib folder, where i have the main.dart file that i want to make the diagram for.

This what I've done so far:

1. Added dcdg: ^2.0.1 to pupspec.yaml
2. Import in dart file i want to make a diagram for, in my case the main.dart in lib folder: import 'package:dcdg/dcdg.dart';
3. Navigated to folder with dart file (in my case the lib folder) and executed:
   flutter pub global run dcdg

I've also tried executing
flutter pub global run dcdg -p /Users/nicolai/Documents/acdc_flutter_app/pubspec.yaml

Im still getting the error :(
Unhandled exception:
NoSuchMethodError: The method 'accept' was called on null.
Receiver: null

Im sorry for all the stupid questions. I just started developing with Flutter so dart and pubs etc are still new for me..

[glesica]

You don't need to import it into your code, nor do you need to add it as a dependency to your project. You can't run it from the lib/ directory. You run it from your package directory (the one with the pubspec.yaml file in it, as I've said earlier and as can be seen in the examples). Here's an example. This is a copy-paste of a terminal session on my machine:

dcdg.dart on  master [?]
➜ pub global activate dcdg
Package dcdg is currently active at version 3.0.0.
Resolving dependencies...
The package dcdg is already activated at newest available version.
To recompile executables, first run `global decativate dcdg`.
Installed executable dcdg.
Activated dcdg 3.0.0.

dcdg.dart on  master [?]
➜ ls
CHANGELOG.md          ROADMAP               build                 pubspec.lock
Dockerfile_build      USAGE.txt             diagram.puml          pubspec.yaml
LICENSE               analysis_options.yaml example               test
README.md             bin                   lib                   tool

dcdg.dart on  master [?]
➜ pub global run dcdg -o diagram.puml

Beyond that, I'm not sure how else I can help you. Sorry.

[Nicolaidam]

Ahhh i think i have the problem. When i run "flutter pub global activate dcdg" i get this warning:

So the the pub is installed in $HOME/Documents/flutter/.pub-cache/bin, and thats the reason why i get the error "NoSuchMethodError: The method 'accept' was called on null." when i run the dsdg.

Will it help to add the path: export PATH="$PATH":"$HOME/Documents/flutter/.pub-cache/bin"
to .bashrc? Im not really familiar with this way of using the mac terminal yet

Thank you so much!