Delta debug prune

[oharboe]

Can be merged now, but The-OpenROAD-Project/OpenROAD-flow-scripts#3991 must then be merged before ORFS upgrades to latest OpenROAD.

[github-actions]

clang-tidy review says "All clean, LGTM! 👍"

[gemini-code-assist]

Code Review

This pull request replaces the deltaDebug.py script with an improved whittle.py script for minimizing test cases. The changes include removing the old script and its tests, enhancing whittle.py with better progress reporting (including elapsed time, file size reduction, and log tails for long-running steps), and adding comprehensive documentation. A new Claude skill is also introduced to automate the issue triage process using whittle.py. My review focuses on improving the user-friendliness of the progress reporting and suggesting a minor refinement to a shell command in the documentation.

[gemini-code-assist]

For conciseness and robustness, you can combine the two sed commands into a single one using a regular expression to match either -no_init or -no_splash.

Suggested change

	sed -i 's/openroad -no_init/openroad -exit -no_init/g' run-me-*.sh
	sed -i 's/openroad -no_splash/openroad -exit -no_splash/g' run-me-*.sh
	sed -i 's/openroad \(-no_init\|-no_splash\)/openroad -exit \1/g' run-me-*.sh

[gemini-code-assist]

The current implementation of format_duration for values between 60 and 3600 seconds is very coarse, as it only shows minutes (e.g., 119 seconds is displayed as '1m'). This can be misleading. A more precise format including seconds for durations less than an hour would be more user-friendly. Note that this change will require updating the corresponding tests in test_whittle.py.

Suggested change

	@staticmethod
	def format_duration(seconds):
	"""Format seconds into a human-readable duration string."""
	seconds = int(seconds)
	if seconds < 60:
	return f"{seconds}s"
	if seconds < 3600:
	return f"{seconds // 60}m"
	return f"{seconds // 3600}h {seconds % 3600 // 60:02d}m"
	@staticmethod
	def format_duration(seconds):
	"""Format seconds into a human-readable duration string."""
	seconds = int(seconds)
	if seconds < 60:
	return f"{seconds}s"
	m, s = divmod(seconds, 60)
	h, m = divmod(m, 60)
	if h > 0:
	return f"{h}h {m:02d}m"
	return f"{m}m {s:02d}s"

[gemini-code-assist]

With the suggested improvement to format_duration in whittle.py, these tests need to be updated to reflect the more precise output format.

Suggested change

	def test_format_duration(self):
	self.assertEqual(whittle.Whittler.format_duration(30), "30s")
	self.assertEqual(whittle.Whittler.format_duration(90), "1m")
	self.assertEqual(whittle.Whittler.format_duration(120), "2m")
	self.assertEqual(whittle.Whittler.format_duration(3661), "1h 01m")
	self.assertEqual(whittle.Whittler.format_duration(7200), "2h 00m")
	def test_format_duration(self):
	self.assertEqual(whittle.Whittler.format_duration(30), "30s")
	self.assertEqual(whittle.Whittler.format_duration(90), "1m 30s")
	self.assertEqual(whittle.Whittler.format_duration(120), "2m 00s")
	self.assertEqual(whittle.Whittler.format_duration(3661), "1h 01m")
	self.assertEqual(whittle.Whittler.format_duration(7200), "2h 00m")