Enable verbose debugging when github actions etc. requests it (#59551)

Author: IanButterworth

NEWS.md

@@ -31,6 +31,7 @@ Command-line option changes
 * The `JULIA_CPU_TARGET` environment variable now supports a `sysimage` keyword to match (or extend) the CPU target used to build the current system image ([#58970]).
 * The `--code-coverage=all` option now automatically throws away sysimage caches so that code coverage can be accurately measured on methods within the sysimage. It is thrown away after startup (and after startup.jl), before any user code is executed ([#59234])
 * New `--trace-eval` command-line option to show expressions being evaluated during top-level evaluation. Supports `--trace-eval=loc` or just `--trace-eval` (show location only), `--trace-eval=full` (show full expressions), and `--trace-eval=no` (disable tracing). Also adds `Base.TRACE_EVAL` global control that takes priority over the command-line option and can be set to `:no`, `:loc`, `:full`, or `nothing` (to use command-line setting). ([#57137])
+* Julia now automatically enables verbose debugging options (`--trace-eval` and `JULIA_TEST_VERBOSE`) when CI debugging has been triggered. i.e. via the "debug logging" UI toggle is enabled on github actions re-runs. Other platforms are supported too ([#59551])
 
 Multi-threading changes
 -----------------------

base/client.jl

@@ -236,6 +236,20 @@ function exec_options(opts)
     global have_color     = colored_text(opts)
     global is_interactive = (opts.isinteractive != 0)
 
+    # Enable verbose debugging options when requested by other frameworks
+    debug_env_vars = (
+        "RUNNER_DEBUG",   # github actions when UI "debug logging" is enabled
+        "CI_DEBUG_TRACE", # gitlab CI when UI "debug" toggle is enabled
+        "SYSTEM_DEBUG",   # azure pipelines when UI "System diagnostics" is enabled
+    )
+    for v in debug_env_vars
+        if get_bool_env(v, false)
+            Base.TRACE_EVAL = Base.TRACE_EVAL === :full ? :full : :loc # Enable --trace-eval (location only)
+            ENV["JULIA_TEST_VERBOSE"] = "true" # Set JULIA_TEST_VERBOSE for this session
+            break
+        end
+    end
+
     # pre-process command line argument list
     arg_is_program = !isempty(ARGS)
     repl = !arg_is_program

doc/src/manual/environment-variables.md

@@ -537,6 +537,15 @@ A few special features are supported:
 
 Enable debug logging for a file or module, see [`Logging`](@ref man-logging) for more information.
 
+### CI Debug Environment Variables
+
+Julia automatically enables verbose debugging options when certain continuous integration (CI) debug environment variables are set. This improves the debugging experience when CI jobs are re-run with debug logging enabled, by automatically:
+
+- Enabling `--trace-eval` (location mode) to show expressions being evaluated
+- Setting `JULIA_TEST_VERBOSE=true` to enable verbose test output
+
+This allows developers to get detailed debugging information from CI runs without modifying their scripts or workflow files.
+
 ### [`JULIA_PROFILE_PEEK_HEAP_SNAPSHOT`](@id JULIA_PROFILE_PEEK_HEAP_SNAPSHOT)
 
 Enable collecting of a heap snapshot during execution via the profiling peek mechanism.