Revision history for haskell-debugger

0.13.2.0 -- 2026-09-17

• Added binary distributions intended for on Linux and macOS.
• Made debug session survive errors in non-essential operations.
• Added support to visualize variables bound in earlier stack frames.
• Improved reporting of session loading and other errors.
• Switched to loading all components from cradle, from hie-bios-0.20+
• Added support for Stack annotations with optional source locations.
• Added support for GHC 10.1
• Removed outdated 'install using stack' README section.
• Fixed unintended loudness of hdb server -v0.
• Restricted debug console to inner scope of module stopped at.

0.13.1.0 -- 2026-04-28

• Fix critical bug which caused certain breakpoints to be overwritten by or confused with breakpoints from separate modules.
• Fix: Make forcing a thunk invalidate all threads

0.13.0.0 -- 2026-04-24

Features:

• Launch the external-interpreter directly in User's Terminal. That is, VSCode terminal will run the external interpreter, which is evaluating the debuggee directly, directly (rather than a proxy program).
  • When using the internal interpreter, falls back to running hdb proxy.
• Add support for import Module statements at the debug REPL.
• Add logpoints support.
• Support for nightly GHC 9.15, leveraging external interpreter commands.

Bug fixes:

• Fix: Import failed where depended-upon package was incorrectly considered hidden
• Fix: Respond cleanly to DAP client with ErrorResponse on exceptions, rather than crashing the session.
• Fix: terminate/disconnect/terminated wasn't following DAP properly, resulting in premature exiting crashes
• Fix: Debugger.View.Class cannot be found in certain multi-repl sessions
• Fix: Make custom DebugViews instances work for newtypes
• Fix: Display more unevaluatable closures as <fn> rather than as thunks _
• Fix: Inherit the language extensions at any given breakpoint source to the REPL
• Fix: Don't print certain evaluation results in duplicate
• Fix: Set scopeExpensive=true for Module and Global

Additionally, the debugger internals and the testsuite were considerably refactored and improved, paving the way for better, faster changes, with more confidence.

0.12.3.0 -- 2026-03-11

• Updated extension logo to be Haskell's logo

0.12.2.0 -- 2026-03-09

• Bug fixes and improved progress reporting
• It's now possible interactively debug GHC itself! This works by simply:
  1. Using GHC 9.14 as the boot compiler
  2. Creating .vscode/launch.json in the GHC tree root with
     • entryFile: "ghc/Main.hs"
     • entryArgs: "["-B${workspaceFolder}/_build/stage0/lib/", "Test.hs"]"

0.12.1.0 -- 2026-02-24

• Update range of supported runtime haskell-debugger-view versions to 0.2.*

0.12.0.0 -- 2026-02-24

• Improved exceptions support!
  • Break-on-exception breakpoints now provide source locations
  • And exception callstacks based on the ExceptionAnnotation mechanism.
• Introduced stacktraces support!
  • Stack frames decoded from interpreter frames with breakpoints are displayed
  • Stack frames decoded from IPE information available for compiled code frames too
  • Custom stack annotations will also be displayed
• Use the external interpreter by default!
  • Paves the way for separating debugger threads vs debuggee threads in multi-threaded debugging
  • Allows debuggee vs debugger output to be separated by construction
• Windows is now supported when using the external interpreter (default)
• Fixed bug where existential constraints weren't displayed in the variables pane
• Plus more bug fixes, refactors, test improvements, and documentation updates.

0.11.0.0 -- 2026-01-05

• Introduce but don't yet expose infrastructure for debugging multi-threaded programs and constructing better callstacks.
• Introduce RemoteExpr: A DSL for evaluation on the remote process.
  • This allows us to cache remote expressions at a much greater granularity which improves performance and memory usage significantly in the long term.
• Improves logging to Debug Console
• Augment haskell-debugger-version, version 0.2.0.0 with
  • This release brings the Program DSL which allows the debuggee to be queried from a custom instance, making it possible to implement visualisations which rely on e.g. evaluatedness of a term.
    • See the DebugView instance for [a] for an example of a more complex instance.
  • haskell-debugger-0.11.0.0 is only compatible with haskell-debugger-view-0.2.0.0 and will abort if unsupported haskell-debugger-view versions are found in the dependencies closure
• Bump dap minimum version to 0.3.1
• Various fixes and code improvements

0.10.1.0 -- 2025-11-21

• Fixes critical bug which prevented debugger from being used with non-boot dependencies!

0.10.0.0 -- 2025-11-18

• Adds Custom Debug Visualisations!
  • The value inspection internals were refactored to always try first to use a custom visualization and fallback to the general-case visualization which mimics the heap representation of a value.
  • We ship a handful of custom visualisations for base types like String, Int, etc, and for types from a few core packages: Text, ByteString, Map and IntMap.
  • The user can add custom visualizations for the desired types by implementing an instance for DebugView from haskell-debugger-view
    • At runtime, hdb will pick up the DebugView instances in scope and use them when possible.
  • When the package dependency closure includes haskell-debugger-view, we will use that unit specifically. When it is not in the dependencies, we will load a built-in version in memory.
• Evaluate requests now return a structured and expandable response, akin to the variables pane
  • To show the whole value inline one can recover the previous behavior by calling show on the value to display.
  • This makes it possible to have structured results in the "Watch" pane.
• Adds support for conditional breakpoints and hit count breakpoints
• Bug fixes in variable inspection
• Bug fixes in multiple-home-units

0.9.0.0 -- 2025-10-13

Main changes

• Run a proxy program with runInTerminal to allow stdin via the terminal process, if the client supports it.

Bug fixes

• Fix bug where build failures were reported in a pop-up rather than stderr
• Fix crashes panicking with findUnitIdOfEntryFile
• Fix cli bug by use absolute entryFile path
• Fix bug caused by not canonicalizing special target and root
• Fix in variable expansion (expand Terms iteratively as the user expands the tree)

0.8.0.0 -- 2025-09-19

• Allow defaults for all settings except entryFile and return a proper error in that case
• Fix bug that crashed debugger when attempting to load newtype constructor closure
• Fix bug that broke displaying newtype variables
• (Vscode) Allow the debugger to be run without a launch.json file
• Don't display functions as a forceable thunk, instead just the type
• Add --version flag

0.7.0.0 -- 2025-09-10

• Fix line buffering of debuggee output (thus, stepping through a print line, will indeed print it to the console now).
  • In fact, this was only caused by not building with --enable-executable-dynamic

0.6.0.0 -- 2025-09-10

• Improve unit handling and fix running when main functions exist across different units
  • Add interactive home unit id
  • The entry file determines which of the mains to run.
• Add proper option parsing
• Add preview version of hdb cli interactive mode, as an alternative to DAP server
  • Experimental and incomplete
• Fix: output uncaught exceptions to stderr
• Fix: output eval completed result to console

0.5.0.0 -- 2025-08-26

• Compatibility with GHC 9.14
• Add support for stepping out of functions as a tech preview
• Use implicit cradle discovery to better support multiple configurations, mirroring HLS (and thus providing a more similar experience)
• Query the GHC runtime version via hie-bios, now honoring e.g. with-compiler: ... in cabal.project to fetch the right GHC version
• Rename package from ghc-debugger to haskell-debugger, and ghc-debug-adapter to hdb, to be consistent with other tools and ecosystems and to avoid ambiguity with ghc-debug (program heap analysis library and tool)
• Use cache directories for hdb to have faster startup times. This will only be enabled for compilers supporting the upcoming .gbc (compiled bytecode artifact) files.

0.4.0.0 -- 2025-06-27

• Add support for debugging multiple home units (MHU)

0.3.0.0 -- 2025-06-07

• Critical fixes for variables inspection

0.2.0.0 -- 2025-05-13

• Significantly improves variable inspection and expansion commands.

0.1.0.0 -- 2025-05-08

• First version. Released on an unsuspecting world.