#4956 mutual depends yield stack overflow

[dan hayes]

build_info() or bug_report()
WxMaxima version: 26.01.0_MSW
Using wxWidgets version: wxWidgets 3.2.9
Maxima version: 5.49.0
Maxima build date: 2026-01-02 21:27:51
Host type: x86_64-w64-mingw32
System type: Win32 10.0.19041 X86-64
Lisp implementation type: SBCL
Lisp implementation version: 2.6.0

---

[kill(f,r1,r2,r12,w),depends(f,[r1,r2],[r1,r2],w), eq: expand(((1-w^2)diff(f,w,2)-2wdiff(f,w))(1/r1^2+1/r2^2))];

that runs ok but next do

[depends(w,[r1,r2]),diff(w,r1)];

and get red sriting rather lengthy ...stder stream INFO.....Lisp error
Why ? get tje sa,e error even if do

---

[kill(w),depends(w,[r1,r2]),diff(w,r1)];

Strangely if i don't do the first one at top do not get the error. Clearly a bug esp since did kill(w) first
which should be the same as restarting maxima

[Barton Willis]

Your example has at least one syntax error--a missing explicit * for multiplication. Try setting display2d to false and revise your report using copy and paste.

Once it is possible to cut-and-paste your example without any syntax errors, maybe somebody will resolve the problem you are seeing.

[kill(f,r1,r2,r12,w),depends(f,[r1,r2],[r1,r2],w), eq: expand(((1-w^2)diff(f,w,2)-2wdiff(f,w))(1/r1^2+1/r2^2))];

incorrect syntax: diff is not an infix operator
expand(((1-w^2)diff(

[David Scherfgen]

The problem is that he pasted his code verbarim without proper formatting, and SourceForge's Markdown parser then interprets * as formatting instruction.

[Stavros Macrakis]

In any case, the expand calculation (with the formatting error) is irrelevant.

Simpler case:

depends(y,x);
depends(x,y);
diff(x,Q);    <<< Stack overflow
diff(y,Q);    <<< Stack overflow