Improve Cython debugging

[mkoeppe]

1. Store cython_debug in site-packages/sage/cython_debug instead of in the Cython build directory.

2. Upgrade cysignals:

Tarball: https://pypi.python.org/packages/92/15/9ca4a50304fca8debaccac2e9b630626c13f4c91992ca5a86f52732bb983/cysignals-1.6.9.tar.gz#md5=d8155169fefb8ea9c036c2a8ee1495bd

CC: @kiwifb

Component: build

Author: Jeroen Demeyer

Branch/Commit: fa789c2

Reviewer: François Bissey

Issue created by migration from https://trac.sagemath.org/ticket/21509

[kiwifb]

Description changed:

--- 
+++ 
@@ -1 +1,5 @@
-fbissey [proposes](https://github.com/sagemath/sage/issues/21480#comment:88) to install cython_debug somewhere in SAGE_LOCAL because it is needed for debugging.
+fbissey [proposes](https://github.com/sagemath/sage/issues/21480#comment:88) to install cython_debug somewhere in SAGE_LOCAL because it is needed for debugging at runtime.
+
+We shouldn't be relying on the sources or the source directories at runtime. In distros most debugging info is usually striped from the runtime executables and libraries and loaded on demand from a central location. We should similarly install this debugging info rather than keeping it in the source tree. 
+
+Do we know what other `cython` projects do, if they do anything?

[mkoeppe]

comment:3

Can you explain what 'cython_debug' is used for precisely, in the description? (Or point to a reference?)

[jdemeyer]

comment:4

Replying to @mkoeppe:

Can you explain what 'cython_debug' is used for precisely, in the description? (Or point to a reference?)

It is used by https://github.com/sagemath/cysignals/blob/master/src/scripts/cysignals-CSI-helper.py#L43

[jdemeyer]

Replying to @mkoeppe:

fbissey proposes to install cython_debug somewhere in SAGE_LOCAL because it is needed for debugging at runtime.

See #21480 comment:127 where I question this proposal.

[jdemeyer]

Description changed:

--- 
+++ 
@@ -1,5 +1,9 @@
-fbissey [proposes](https://github.com/sagemath/sage/issues/21480#comment:88) to install cython_debug somewhere in SAGE_LOCAL because it is needed for debugging at runtime.
+fbissey [proposes](https://github.com/sagemath/sage/issues/21480#comment:88) to install `cython_debug` somewhere in `SAGE_LOCAL` because it is needed for debugging at runtime.
+
+jdemeyer comments that this is pointless if you don't install the *source files* in `$SAGE_LOCAL` since debugging also requires the sources. So it might make more sense to keep it somewhere inside `$SAGE_SRC` (but not necessarily in `$SAGE_CYTHONIZED`).
 
 We shouldn't be relying on the sources or the source directories at runtime. In distros most debugging info is usually striped from the runtime executables and libraries and loaded on demand from a central location. We should similarly install this debugging info rather than keeping it in the source tree. 
 
 Do we know what other `cython` projects do, if they do anything?
+
+See also #21886.

[jdemeyer]

Dependencies: #24690

[jdemeyer]

Description changed:

--- 
+++ 
@@ -1,9 +1,7 @@
 fbissey [proposes](https://github.com/sagemath/sage/issues/21480#comment:88) to install `cython_debug` somewhere in `SAGE_LOCAL` because it is needed for debugging at runtime.
 
-jdemeyer comments that this is pointless if you don't install the *source files* in `$SAGE_LOCAL` since debugging also requires the sources. So it might make more sense to keep it somewhere inside `$SAGE_SRC` (but not necessarily in `$SAGE_CYTHONIZED`).
+This depends on #24690 which installs the source files in `site-packages`. The debugging information should probably also be stored there.
 
 We shouldn't be relying on the sources or the source directories at runtime. In distros most debugging info is usually striped from the runtime executables and libraries and loaded on demand from a central location. We should similarly install this debugging info rather than keeping it in the source tree. 
 
-Do we know what other `cython` projects do, if they do anything?
-
 See also #21886.

[jdemeyer]

Branch: u/jdemeyer/ticket/21509

[jdemeyer]

New commits:

1bf128e	Install the .pyx files
996759c	No longer add SAGE_SRC to sys.path
3e99963	Install cython_debug in site-packages/sage

[jdemeyer]

Commit: 3e99963

[jdemeyer]

Description changed:

--- 
+++ 
@@ -1,7 +1,5 @@
-fbissey [proposes](https://github.com/sagemath/sage/issues/21480#comment:88) to install `cython_debug` somewhere in `SAGE_LOCAL` because it is needed for debugging at runtime.
+1. Store `cython_debug` in `site-packages/sage/cython_debug` instead of in the Cython build directory.
 
-This depends on #24690 which installs the source files in `site-packages`. The debugging information should probably also be stored there.
+2. Upgrade cysignals.
 
-We shouldn't be relying on the sources or the source directories at runtime. In distros most debugging info is usually striped from the runtime executables and libraries and loaded on demand from a central location. We should similarly install this debugging info rather than keeping it in the source tree. 
-
-See also #21886.
+3. Fix `libpython.py` from Cython to avoid a double close: https://github.com/cython/cython/pull/2095

[jdemeyer]

Author: Jeroen Demeyer