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@indygregindygreg commented May 15, 2023

By convention make targets that don't refer to a file have a dependency on the fake .PHONY target/file. This ensures that these targets are always evaluated because there is no rule to create a .PHONY file and that will force make to think the rule is out of date and needs to be rebuilt.

This commit consistently associates our virtual targets with .PHONY by declaring the .PHONY dependency immediately above the make rule.

Before, some .PHONY associations were inline (as this patch establishes). Others were defined in common blocks. Even others were defined incorrectly, actually assigning a .PHONY variable instead of operating on the make target!

Before, not all virtual targets had .PHONY associations. And there were some defined .PHONY associations in common blocks whose targets had long been deleted.

Hopefully the unified convention will prevent things from getting out of sync going forward.

Why do this?

First, consistency is good. Now people don't have to know to look for a separate block of .PHONY attribution. Hopefully this prevents missing .PHONY annotations going forward.

Second, there are some cases where virtual make targets are virtual / phony when they shouldn't be. These are creating race conditions and avoidable rebuilds across multiple make invocations. e.g. a make all

  • make install invocation will perform PGO+BOLT if BOLT is enabled because profile-opt and bolt-opt are phony and always invoked. I plan follow-ups to this cleanup to fix some bugs I've run into.

By convention make targets that don't refer to a file have a dependency on the fake `.PHONY` target/file. This ensures that these targets are always evaluated because there is no rule to create a `.PHONY` file and that will force make to think the rule is out of date and needs to be rebuilt. This commit consistently associates our virtual targets with `.PHONY` by declaring the `.PHONY` dependency immediately above the make rule. Before, some `.PHONY` associations were inline (as this patch establishes). Others were defined in common blocks. Even others were defined incorrectly, actually assigning a `.PHONY` variable instead of operating on the make target! Before, not all virtual targets had `.PHONY` associations. And there were some defined `.PHONY` associations in common blocks whose targets had long been deleted. Hopefully the unified convention will prevent things from getting out of sync going forward. Why do this? First, consistency is good. Now people don't have to know to look for a separate block of `.PHONY` attribution. Hopefully this prevents missing `.PHONY` annotations going forward. Second, there are some cases where virtual make targets are virtual / phony when they shouldn't be. These are creating race conditions and avoidable rebuilds across multiple `make` invocations. e.g. a `make all` + `make install` invocation will perform PGO+BOLT if BOLT is enabled because `profile-opt` and `bolt-opt` are phony and always invoked. I plan follow-ups to this cleanup to fix some bugs I've run into.
@erlend-aaslanderlend-aasland changed the title gh-104490: consistently define phony make targetsgh-104490: Consistently define phony make targetsMay 15, 2023
@erlend-aaslanderlend-aasland enabled auto-merge (squash) May 15, 2023 08:24
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This is a very nice improvement; thanks!

@erlend-aaslanderlend-aasland merged commit a6bcc8f into python:mainMay 15, 2023
carljm added a commit to carljm/cpython that referenced this pull request May 15, 2023
* main: (29 commits) pythongh-101819: Fix _io clinic input for unused base class method stubs (python#104418) pythongh-101819: Isolate `_io` (python#101948) Bump mypy from 1.2.0 to 1.3.0 in /Tools/clinic (python#104501) pythongh-104494: Update certain Tkinter pack/place tests for Tk 8.7 errors (python#104495) pythongh-104050: Run mypy on `clinic.py` in CI (python#104421) pythongh-104490: Consistently define phony make targets (python#104491) pythongh-67056: document that registering/unregistering an atexit func from within an atexit func is undefined (python#104473) pythongh-104487: PYTHON_FOR_REGEN must be minimum Python 3.10 (python#104488) pythongh-101282: move BOLT config after PGO (pythongh-104493) pythongh-104469 Convert _testcapi/float.c to use AC (pythongh-104470) pythongh-104456: Fix ref leak in _ctypes.COMError (python#104457) pythongh-98539: Make _SSLTransportProtocol.abort() safe to call when closed (python#104474) pythongh-104337: Clarify random.gammavariate doc entry (python#104410) Minor improvements to typing docs (python#104465) pythongh-87092: avoid gcc warning on uninitialized struct field in assemble.c (python#104460) pythonGH-71383: IDLE - Document testing subsets of modules (python#104463) pythongh-104454: Fix refleak in AttributeError_reduce (python#104455) pythongh-75710: IDLE - add docstrings and comments to editor module (python#104446) pythongh-91896: Revert some very noisy DeprecationWarnings for `ByteString` (python#104424) Add a mention of PYTHONBREAKPOINT to breakpoint() docs (python#104430) ...
carljm added a commit to carljm/cpython that referenced this pull request May 15, 2023
* main: (204 commits) pythongh-101819: Fix _io clinic input for unused base class method stubs (python#104418) pythongh-101819: Isolate `_io` (python#101948) Bump mypy from 1.2.0 to 1.3.0 in /Tools/clinic (python#104501) pythongh-104494: Update certain Tkinter pack/place tests for Tk 8.7 errors (python#104495) pythongh-104050: Run mypy on `clinic.py` in CI (python#104421) pythongh-104490: Consistently define phony make targets (python#104491) pythongh-67056: document that registering/unregistering an atexit func from within an atexit func is undefined (python#104473) pythongh-104487: PYTHON_FOR_REGEN must be minimum Python 3.10 (python#104488) pythongh-101282: move BOLT config after PGO (pythongh-104493) pythongh-104469 Convert _testcapi/float.c to use AC (pythongh-104470) pythongh-104456: Fix ref leak in _ctypes.COMError (python#104457) pythongh-98539: Make _SSLTransportProtocol.abort() safe to call when closed (python#104474) pythongh-104337: Clarify random.gammavariate doc entry (python#104410) Minor improvements to typing docs (python#104465) pythongh-87092: avoid gcc warning on uninitialized struct field in assemble.c (python#104460) pythonGH-71383: IDLE - Document testing subsets of modules (python#104463) pythongh-104454: Fix refleak in AttributeError_reduce (python#104455) pythongh-75710: IDLE - add docstrings and comments to editor module (python#104446) pythongh-91896: Revert some very noisy DeprecationWarnings for `ByteString` (python#104424) Add a mention of PYTHONBREAKPOINT to breakpoint() docs (python#104430) ...
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Handle virtual / phony make targets consistently and more robustly

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@indygreg@erlend-aasland@arhadthedev@bedevere-bot