Re: SCons misses a dependency which results in incorrect output.
Bill Deegan <[email protected]> Wed, 16 Jul 2025 15:18:54 -0700
| Newsgroups | gmane.comp.programming.tools.scons.user |
|---|---|
| Message-ID | <CAEyG4CFREFnhRwtpwbeAMg6wzoHDyYUc5BgBstBkrLPq6RLkjg@mail.gmail.com> |
--===============3554158185219751703== Content-Type: multipart/alternative; boundary="000000000000edd6d6063a134768" --000000000000edd6d6063a134768 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Did you read my explanation and how to fix it in your environment assuming command.sh is similar to what's really happening in your build? On Wed, Jul 16, 2025 at 3:16=E2=80=AFPM Bill Deegan <bill@baddogconsulting.= com> wrote: > It's an enhancement request. > > The bug is in your command.sh script. > I'll change the description and text. > > > > On Wed, Jul 16, 2025 at 12:56=E2=80=AFPM Tal Dayan <[email protected]> wrote: > >> Hi Bill, I will file an issue. >> >> I don't think it's safe for SCons to assume that once a program writes a= n >> output file it can't crash. >> >> On Wed, Jul 16, 2025 at 12:45=E2=80=AFPM Bill Deegan <bill@baddogconsult= ing.com> >> wrote: >> >>> Arguably your command.sh is incorrectly written. >>> >>> It copies the file and then checks it's contents and exits with error >>> status if there improper. >>> >>> So a quick fix would be to check the input before copying the file. >>> >>> From the URL you posted in other email here's the command.sh >>> #!/bin/bash >>> # Usage: ./command input > output >>> >>> # Copy source to destination >>> cp "$1" "$2" >>> >>> # If the input file stats with 'bad' inject an error AFTER creating the >>> output file. >>> >>> first_line=3D$(head -n 1 "$1") >>> >>> if [[ "$first_line" =3D=3D bad* ]]; then >>> exit 1 >>> fi >>> >>> exit 0 >>> >>> Change it to this: >>> #!/bin/bash >>> # Usage: ./command input > output >>> >>> # If the input file stats with 'bad' inject an error AFTER creating the >>> output file. >>> >>> first_line=3D$(head -n 1 "$1") >>> >>> if [[ "$first_line" =3D=3D bad* ]]; then >>> exit 1 >>> fi >>> >>> # Copy source to destination >>> cp "$1" "$2" >>> >>> exit 0 >>> >>> Results: >>> >>> % ./run.sh >>> >>> ----- Iteration 1: file1 =3D 'good' ----- >>> >>> scons: Reading SConscript files ... >>> scons: done reading SConscript files. >>> scons: Building targets ... >>> scons: building `file2' because it doesn't exist >>> ./command.sh file1 file2 >>> +-file2 >>> +-file1 >>> scons: done building targets. >>> >>> File1 >>> MD5 (file1) =3D d7f986677d9f563bd1794b09d82206a3 >>> 1 good >>> >>> File2 >>> MD5 (file2) =3D d7f986677d9f563bd1794b09d82206a3 >>> 1 good >>> >>> DBlite: >>> =3D=3D=3D .: >>> file1: d7f986677d9f563bd1794b09d82206a3 1752694898 5 >>> file2: d7f986677d9f563bd1794b09d82206a3 1752694898 5 >>> file1: d7f986677d9f563bd1794b09d82206a3 1752694898 5 >>> 2dbc2dce125a753309a27b7d5157aaaa [./command.sh $SOURCE $TARGET] >>> >>> ----- Iteration 2: file1 =3D 'bad' ----- >>> >>> scons: Reading SConscript files ... >>> scons: done reading SConscript files. >>> scons: Building targets ... >>> scons: rebuilding `file2' because `file1' changed >>> ./command.sh file1 file2 >>> scons: *** [file2] Error 1 >>> +-file2 >>> +-file1 >>> scons: building terminated because of errors. >>> >>> File1 >>> MD5 (file1) =3D df207dc9143c6fabf60b69b9c3035103 >>> 1 bad >>> >>> File2 >>> md5: file2: No such file or directory >>> cat: file2: No such file or directory >>> >>> DBlite: >>> =3D=3D=3D .: >>> file1: df207dc9143c6fabf60b69b9c3035103 1752694898 4 >>> file2: d7f986677d9f563bd1794b09d82206a3 1752694898 5 >>> file1: d7f986677d9f563bd1794b09d82206a3 1752694898 5 >>> 2dbc2dce125a753309a27b7d5157aaaa [./command.sh $SOURCE $TARGET] >>> >>> ----- Iteration 3: file1 =3D 'good' ----- >>> >>> scons: Reading SConscript files ... >>> scons: done reading SConscript files. >>> scons: Building targets ... >>> scons: building `file2' because it doesn't exist >>> ./command.sh file1 file2 >>> +-file2 >>> +-file1 >>> scons: done building targets. >>> >>> File1 >>> MD5 (file1) =3D d7f986677d9f563bd1794b09d82206a3 >>> 1 good >>> >>> File2 >>> MD5 (file2) =3D d7f986677d9f563bd1794b09d82206a3 >>> 1 good >>> >>> DBlite: >>> =3D=3D=3D .: >>> file1: d7f986677d9f563bd1794b09d82206a3 1752694899 5 >>> file2: d7f986677d9f563bd1794b09d82206a3 1752694899 5 >>> file1: d7f986677d9f563bd1794b09d82206a3 1752694899 5 >>> 2dbc2dce125a753309a27b7d5157aaaa [./command.sh $SOURCE $TARGET] >>> >>> There's not presently logic in SCons to delete target files if the >>> associated action yields an error. >>> >>> I think what you want is equivalent to makes .DELETE_ON_FAILURE, there'= s >>> actually a SO question on this: >>> >>> https://stackoverflow.com/questions/29546276/scons-delete-target-on-fai= lure-of-any-action >>> >>> Please go ahead and file an enhancement request to add equivalent >>> to DELETE_ON_FAILURE, please include your reproducer scripts. >>> >>> -Bill >>> >>> On Wed, Jul 16, 2025 at 10:44=E2=80=AFAM Tal Dayan <[email protected]> wrot= e: >>> >>>> Looking at the end state of scons after invocation #3, the actual md5 >>>> of file2 doesn't match its md5 in the dblite. >>>> >>>> https://i.imgur.com/NGco3yQ.png >>>> >>>> On Wed, Jul 16, 2025 at 10:33=E2=80=AFAM Tal Dayan <[email protected]> wro= te: >>>> >>>>> Hi Keith, I updated the example files here >>>>> https://github.com/FPGAwars/apio/issues/676 >>>>> >>>>> They now include the md5 of the files and a dump of .sconsign.dblite >>>>> >>>>> On Wed, Jul 16, 2025 at 10:08=E2=80=AFAM Keith Prussing <kprussing74@= gmail.com> >>>>> wrote: >>>>> >>>>>> I suspect it's because `file1` has the same hash in the >>>>>> .sconsign.dblite as the last "good" build (i.e. the first one). Thus >>>>>> you get the line "scons: `file2' is up to date." on the third run. >>>>>> However, I am not an expert in the specifics of SCons' hashing >>>>>> methods. >>>>>> >>>>>> On Wed, Jul 16, 2025 at 12:38=E2=80=AFPM Tal Dayan <[email protected]> w= rote: >>>>>> > >>>>>> > Hi all, >>>>>> > >>>>>> > We encountered this problem with the nextpnr tool and created here >>>>>> a small and independent example that demonstrates it. >>>>>> > >>>>>> > In the example below, a shell script 'command.sh' reads the source >>>>>> file 'file1' and writes it to the target file 'file2'. However, if t= he >>>>>> > source file starts with 'bad' it exits with an error code, *after* >>>>>> creating the target file. >>>>>> > >>>>>> > The script `run.sh', runs scons three times with these values of >>>>>> the source file file1 'good', 'bad', and 'good'. The expectation is= that >>>>>> after the third scons run, file2 should contain the value 'good' but= it >>>>>> contains the value 'bad'. >>>>>> > >>>>>> > Do we miss anything or is it simply a bug? >>>>>> > >>>>>> > SConstruct: >>>>>> > >>>>>> > ---------------------------------------------- >>>>>> > >>>>>> > # SCons environment >>>>>> > >>>>>> > env =3D Environment() >>>>>> > >>>>>> > >>>>>> > # Copy file1 =E2=86=92 file2 using command.sh >>>>>> > >>>>>> > # Inject an error if file1 starts with 'bad" >>>>>> > >>>>>> > file2 =3D env.Command( >>>>>> > >>>>>> > target=3D'file2', >>>>>> > >>>>>> > source=3D'file1', >>>>>> > >>>>>> > action=3D'./command.sh $SOURCE > $TARGET' >>>>>> > >>>>>> > ) >>>>>> > >>>>>> > >>>>>> > # Make 'file2' the default target >>>>>> > >>>>>> > Default(file2) >>>>>> > >>>>>> > ---------------------------------------------- >>>>>> > >>>>>> > >>>>>> > command.sh: >>>>>> > >>>>>> > ---------------------------------------------- >>>>>> > >>>>>> > #!/bin/bash >>>>>> > >>>>>> > # Usage: ./command input > output >>>>>> > >>>>>> > >>>>>> > # Read from the first argument and copy to stdout >>>>>> > >>>>>> > cat "$1" >>>>>> > >>>>>> > >>>>>> > # If the input file starts with 'bad', inject an error AFTER >>>>>> creating the output file. >>>>>> > >>>>>> > >>>>>> > first_line=3D$(head -n 1 "$1") >>>>>> > >>>>>> > >>>>>> > if [[ "$first_line" =3D=3D bad* ]]; then >>>>>> > >>>>>> > exit 1 >>>>>> > >>>>>> > fi >>>>>> > >>>>>> > >>>>>> > exit 0 >>>>>> > >>>>>> > ---------------------------------------------- >>>>>> > >>>>>> > >>>>>> > >>>>>> > run.sh >>>>>> > >>>>>> > ---------------------------------------------- >>>>>> > >>>>>> > #!/bin/bash >>>>>> > >>>>>> > >>>>>> > # Clean up. >>>>>> > >>>>>> > rm -f .sconsign.dblite >>>>>> > >>>>>> > rm -f file[12] >>>>>> > >>>>>> > >>>>>> > echo >>>>>> > >>>>>> > echo "---- Iteration 1: file1 =3D 'good'" >>>>>> > >>>>>> > echo "good" > file1 >>>>>> > >>>>>> > scons >>>>>> > >>>>>> > echo >>>>>> > >>>>>> > >>>>>> > echo "File1" >>>>>> > >>>>>> > cat -n file1 >>>>>> > >>>>>> > >>>>>> > echo "File2" >>>>>> > >>>>>> > cat -n file2 >>>>>> > >>>>>> > >>>>>> > >>>>>> > echo >>>>>> > >>>>>> > echo "---- Iteration 2: file1 =3D 'bad'" >>>>>> > >>>>>> > echo "bad" > file1 >>>>>> > >>>>>> > cat -n file1 >>>>>> > >>>>>> > scons >>>>>> > >>>>>> > echo >>>>>> > >>>>>> > >>>>>> > echo "File1" >>>>>> > >>>>>> > cat -n file1 >>>>>> > >>>>>> > >>>>>> > echo "File2" >>>>>> > >>>>>> > cat -n file2 >>>>>> > >>>>>> > >>>>>> > echo >>>>>> > >>>>>> > echo "---- Iteration 3: file1 =3D 'good'" >>>>>> > >>>>>> > echo "good" > file1 >>>>>> > >>>>>> > cat -n file1 >>>>>> > >>>>>> > scons >>>>>> > >>>>>> > echo >>>>>> > >>>>>> > >>>>>> > echo "File1" >>>>>> > >>>>>> > cat -n file1 >>>>>> > >>>>>> > >>>>>> > echo "File2" >>>>>> > >>>>>> > cat -n file2 >>>>>> > >>>>>> > ---------------------------------------------- >>>>>> > >>>>>> > >>>>>> > >>>>>> > Run log: >>>>>> > >>>>>> > ---------------------------------------------- >>>>>> > >>>>>> > $ ./run.sh >>>>>> > >>>>>> > >>>>>> > ---- Iteration 1: file1 =3D 'good' >>>>>> > >>>>>> > scons: Reading SConscript files ... >>>>>> > >>>>>> > scons: done reading SConscript files. >>>>>> > >>>>>> > scons: Building targets ... >>>>>> > >>>>>> > ./command.sh file1 > file2 >>>>>> > >>>>>> > scons: done building targets. >>>>>> > >>>>>> > >>>>>> > File1 >>>>>> > >>>>>> > 1 good >>>>>> > >>>>>> > File2 >>>>>> > >>>>>> > 1 good >>>>>> > >>>>>> > >>>>>> > ---- Iteration 2: file1 =3D 'bad' >>>>>> > >>>>>> > 1 bad >>>>>> > >>>>>> > scons: Reading SConscript files ... >>>>>> > >>>>>> > scons: done reading SConscript files. >>>>>> > >>>>>> > scons: Building targets ... >>>>>> > >>>>>> > ./command.sh file1 > file2 >>>>>> > >>>>>> > scons: *** [file2] Error 1 >>>>>> > >>>>>> > scons: building terminated because of errors. >>>>>> > >>>>>> > >>>>>> > File1 >>>>>> > >>>>>> > 1 bad >>>>>> > >>>>>> > File2 >>>>>> > >>>>>> > 1 bad >>>>>> > >>>>>> > >>>>>> > ---- Iteration 1: file1 =3D 'good' >>>>>> > >>>>>> > 1 good >>>>>> > >>>>>> > scons: Reading SConscript files ... >>>>>> > >>>>>> > scons: done reading SConscript files. >>>>>> > >>>>>> > scons: Building targets ... >>>>>> > >>>>>> > scons: `file2' is up to date. >>>>>> > >>>>>> > scons: done building targets. >>>>>> > >>>>>> > >>>>>> > File1 >>>>>> > >>>>>> > 1 good >>>>>> > >>>>>> > File2 >>>>>> > >>>>>> > 1 bad >>>>>> > >>>>>> > ---------------------------------------------- >>>>>> > >>>>>> > _______________________________________________ >>>>>> > Scons-users mailing list >>>>>> > [email protected] >>>>>> > https://pairlist4.pair.net/mailman/listinfo/scons-users >>>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> Keith Prussing >>>>>> _______________________________________________ >>>>>> Scons-users mailing list >>>>>> [email protected] >>>>>> https://pairlist4.pair.net/mailman/listinfo/scons-users >>>>>> >>>>> _______________________________________________ >>>> Scons-users mailing list >>>> [email protected] >>>> https://pairlist4.pair.net/mailman/listinfo/scons-users >>>> >>> _______________________________________________ >>> Scons-users mailing list >>> [email protected] >>> https://pairlist4.pair.net/mailman/listinfo/scons-users >>> >> _______________________________________________ >> Scons-users mailing list >> [email protected] >> https://pairlist4.pair.net/mailman/listinfo/scons-users >> > --000000000000edd6d6063a134768 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable <div dir=3D"ltr"><div>Did you read my explanation and how to fix it in your= environment assuming command.sh is similar to what's really happening = in your build?</div><div><br></div></div><br><div class=3D"gmail_quote gmai= l_quote_container"><div dir=3D"ltr" class=3D"gmail_attr">On Wed, Jul 16, 20= 25 at 3:16=E2=80=AFPM Bill Deegan <<a href=3D"mailto:bill@baddogconsulti= ng.com">[email protected]</a>> wrote:<br></div><blockquote class= =3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rg= b(204,204,204);padding-left:1ex"><div dir=3D"ltr"><div>It's an enhancem= ent request.</div><div><br></div><div>The bug is in your=C2=A0command.sh sc= ript.</div><div>I'll change the description and text.</div><div><br></d= iv><div><br></div></div><br><div class=3D"gmail_quote"><div dir=3D"ltr" cla= ss=3D"gmail_attr">On Wed, Jul 16, 2025 at 12:56=E2=80=AFPM Tal Dayan <<a= href=3D"mailto:[email protected]" target=3D"_blank">[email protected]</a>> wrot= e:<br></div><blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0= .8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir=3D"l= tr">Hi Bill, I will file an issue.<div><br></div><div>I don't think it&= #39;s safe for SCons to assume that once a program writes an output file it= can't crash.=C2=A0</div></div><br><div class=3D"gmail_quote"><div dir= =3D"ltr" class=3D"gmail_attr">On Wed, Jul 16, 2025 at 12:45=E2=80=AFPM Bill= Deegan <<a href=3D"mailto:[email protected]" target=3D"_blank">= [email protected]</a>> wrote:<br></div><blockquote class=3D"gmai= l_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,20= 4,204);padding-left:1ex"><div dir=3D"ltr"><div>Arguably your command.sh is = incorrectly written.</div><div><br></div><div>=C2=A0It copies the file and = then checks it's contents and exits with error status if there improper= .</div><div><br></div><div>So a quick fix would be to check the input befor= e copying the file.</div><div><br></div><div>From the URL you posted in oth= er email here's the command.sh</div><div><span style=3D"font-family:mon= ospace">#!/bin/bash<br># Usage: ./command input > output<br><br># Copy s= ource to destination<br>cp "$1" "$2"<br><br># If the in= put file stats with 'bad' inject an error AFTER creating the output= file.<br><br>first_line=3D$(head -n 1 "$1")<br><br>if [[ "$= first_line" =3D=3D bad* ]]; then<br>=C2=A0 exit 1<br>fi<br><br>exit 0<= /span></div><div><span style=3D"font-family:monospace"><br></span></div><di= v><span style=3D"font-family:monospace">Change it to this:</span></div><div= ><span style=3D"font-family:monospace">#!/bin/bash<br># Usage: ./command in= put > output<br><br># If the input file stats with 'bad' inject = an error AFTER creating the output file.<br><br>first_line=3D$(head -n 1 &q= uot;$1")<br><br>if [[ "$first_line" =3D=3D bad* ]]; then<br>= =C2=A0 exit 1<br>fi<br><br># Copy source to destination<br>cp "$1"= ; "$2"<br><br>exit 0</span><br><br></div><div>Results:</div><div>= <br></div><div><span style=3D"font-family:monospace">% ./run.sh<br><br>----= - Iteration 1: file1 =3D 'good' -----<br><br>scons: Reading SConscr= ipt files ...<br>scons: done reading SConscript files.<br>scons: Building t= argets ...<br>scons: building `file2' because it doesn't exist<br>.= /command.sh file1 file2<br>+-file2<br>=C2=A0 +-file1<br>scons: done buildin= g targets.<br><br>File1<br>MD5 (file1) =3D d7f986677d9f563bd1794b09d82206a3= <br>=C2=A0 =C2=A0 =C2=A01 good<br><br>File2<br>MD5 (file2) =3D d7f986677d9f= 563bd1794b09d82206a3<br>=C2=A0 =C2=A0 =C2=A01 good<br><br>DBlite:<br>=3D=3D= =3D .:<br>file1: d7f986677d9f563bd1794b09d82206a3 1752694898 5<br>file2: d7= f986677d9f563bd1794b09d82206a3 1752694898 5<br>=C2=A0 =C2=A0 =C2=A0 =C2=A0 = file1: d7f986677d9f563bd1794b09d82206a3 1752694898 5<br>=C2=A0 =C2=A0 =C2= =A0 =C2=A0 2dbc2dce125a753309a27b7d5157aaaa [./command.sh $SOURCE $TARGET]<= br><br>----- Iteration 2: file1 =3D 'bad' -----<br><br>scons: Readi= ng SConscript files ...<br>scons: done reading SConscript files.<br>scons: = Building targets ...<br>scons: rebuilding `file2' because `file1' c= hanged<br>./command.sh file1 file2<br>scons: *** [file2] Error 1<br>+-file2= <br>=C2=A0 +-file1<br>scons: building terminated because of errors.<br><br>= File1<br>MD5 (file1) =3D df207dc9143c6fabf60b69b9c3035103<br>=C2=A0 =C2=A0 = =C2=A01 bad<br><br>File2<br>md5: file2: No such file or directory<br>cat: f= ile2: No such file or directory<br><br>DBlite:<br>=3D=3D=3D .:<br>file1: df= 207dc9143c6fabf60b69b9c3035103 1752694898 4<br>file2: d7f986677d9f563bd1794= b09d82206a3 1752694898 5<br>=C2=A0 =C2=A0 =C2=A0 =C2=A0 file1: d7f986677d9f= 563bd1794b09d82206a3 1752694898 5<br>=C2=A0 =C2=A0 =C2=A0 =C2=A0 2dbc2dce12= 5a753309a27b7d5157aaaa [./command.sh $SOURCE $TARGET]<br><br>----- Iteratio= n 3: file1 =3D 'good' -----<br><br>scons: Reading SConscript files = ...<br>scons: done reading SConscript files.<br>scons: Building targets ...= <br>scons: building `file2' because it doesn't exist<br>./command.s= h file1 file2<br>+-file2<br>=C2=A0 +-file1<br>scons: done building targets.= <br><br>File1<br>MD5 (file1) =3D d7f986677d9f563bd1794b09d82206a3<br>=C2=A0= =C2=A0 =C2=A01 good<br><br>File2<br>MD5 (file2) =3D d7f986677d9f563bd1794b= 09d82206a3<br>=C2=A0 =C2=A0 =C2=A01 good<br><br>DBlite:<br>=3D=3D=3D .:<br>= file1: d7f986677d9f563bd1794b09d82206a3 1752694899 5<br>file2: d7f986677d9f= 563bd1794b09d82206a3 1752694899 5<br>=C2=A0 =C2=A0 =C2=A0 =C2=A0 file1: d7f= 986677d9f563bd1794b09d82206a3 1752694899 5<br>=C2=A0 =C2=A0 =C2=A0 =C2=A0 2= dbc2dce125a753309a27b7d5157aaaa [./command.sh $SOURCE $TARGET]</span></div>= <div><br></div><div>There's not presently logic in SCons to delete targ= et files if the associated action yields an error.</div><div><br></div><div= >I think what you want is equivalent to makes .DELETE_ON_FAILURE, there'= ;s actually a SO question on this:</div><div><a href=3D"https://stackoverfl= ow.com/questions/29546276/scons-delete-target-on-failure-of-any-action" tar= get=3D"_blank">https://stackoverflow.com/questions/29546276/scons-delete-ta= rget-on-failure-of-any-action</a></div><div><br></div><div>Please go ahead = and file an enhancement request to add equivalent to=C2=A0DELETE_ON_FAILURE= , please include your reproducer scripts.</div><div><br></div><div>-Bill</d= iv></div><br><div class=3D"gmail_quote"><div dir=3D"ltr" class=3D"gmail_att= r">On Wed, Jul 16, 2025 at 10:44=E2=80=AFAM Tal Dayan <<a href=3D"mailto= :[email protected]" target=3D"_blank">[email protected]</a>> wrote:<br></div><bl= ockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-lef= t:1px solid rgb(204,204,204);padding-left:1ex"><div dir=3D"ltr">Looking at = the end state of scons after invocation #3, the actual md5 of file2 doesn&#= 39;t match its md5 in the dblite.<div><br></div><div><a href=3D"https://i.i= mgur.com/NGco3yQ.png" target=3D"_blank">https://i.imgur.com/NGco3yQ.png</a>= </div></div><br><div class=3D"gmail_quote"><div dir=3D"ltr" class=3D"gmail_= attr">On Wed, Jul 16, 2025 at 10:33=E2=80=AFAM Tal Dayan <<a href=3D"mai= lto:[email protected]" target=3D"_blank">[email protected]</a>> wrote:<br></div>= <blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-= left:1px solid rgb(204,204,204);padding-left:1ex"><div dir=3D"ltr">Hi Keith= , I updated the example files here=C2=A0<a href=3D"https://github.com/FPGAw= ars/apio/issues/676" target=3D"_blank">https://github.com/FPGAwars/apio/iss= ues/676</a><div><br></div><div>They now include the md5 of the files and a = dump of=C2=A0<span style=3D"font-variant-ligatures:no-common-ligatures;colo= r:rgb(0,0,0);font-family:Menlo;font-size:12px">.sconsign.dblite</span></div= > </div><br><div class=3D"gmail_quote"><div dir=3D"ltr" class=3D"gmail_attr">= On Wed, Jul 16, 2025 at 10:08=E2=80=AFAM Keith Prussing <<a href=3D"mail= to:[email protected]" target=3D"_blank">[email protected]</a>> w= rote:<br></div><blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0p= x 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">I suspect = it's because `file1` has the same hash in the<br> .sconsign.dblite as the last "good" build (i.e. the first one). T= hus<br> you get the line "scons: `file2' is up to date." on the third= run.<br> However, I am not an expert in the specifics of SCons' hashing<br> methods.<br> <br> On Wed, Jul 16, 2025 at 12:38=E2=80=AFPM Tal Dayan <<a href=3D"mailto:ta= [email protected]" target=3D"_blank">[email protected]</a>> wrote:<br> ><br> > Hi all,<br> ><br> > We encountered this problem with the nextpnr tool and created here a s= mall and independent example that demonstrates it.<br> ><br> > In the example below, a shell script 'command.sh' reads the so= urce file 'file1' and writes it to the target file 'file2'.= However, if the<br> > source file starts with 'bad' it exits with an error code, *af= ter* creating the target file.<br> ><br> > The script `run.sh', runs scons three times with these values of t= he source file file1 'good', 'bad', and 'good'.=C2= =A0 The expectation is that after the third scons run, file2 should contain= the value 'good' but it contains the value 'bad'.<br> ><br> > Do we miss anything or is it simply a bug?<br> ><br> > SConstruct:<br> ><br> > ----------------------------------------------<br> ><br> > # SCons environment<br> ><br> > env =3D Environment()<br> ><br> ><br> > # Copy file1 =E2=86=92 file2 using command.sh<br> ><br> > # Inject an error if file1 starts with 'bad"<br> ><br> > file2 =3D env.Command(<br> ><br> >=C2=A0 =C2=A0 =C2=A0target=3D'file2',<br> ><br> >=C2=A0 =C2=A0 =C2=A0source=3D'file1',<br> ><br> >=C2=A0 =C2=A0 =C2=A0action=3D'./command.sh $SOURCE > $TARGET'= ;<br> ><br> > )<br> ><br> ><br> > # Make 'file2' the default target<br> ><br> > Default(file2)<br> ><br> > ----------------------------------------------<br> ><br> ><br> > command.sh:<br> ><br> > ----------------------------------------------<br> ><br> > #!/bin/bash<br> ><br> > # Usage: ./command input > output<br> ><br> ><br> > # Read from the first argument and copy to stdout<br> ><br> > cat "$1"<br> ><br> ><br> > # If the input file starts with 'bad', inject an error AFTER c= reating the output file.<br> ><br> ><br> > first_line=3D$(head -n 1 "$1")<br> ><br> ><br> > if [[ "$first_line" =3D=3D bad* ]]; then<br> ><br> >=C2=A0 =C2=A0exit 1<br> ><br> > fi<br> ><br> ><br> > exit 0<br> ><br> > ----------------------------------------------<br> ><br> ><br> ><br> > run.sh<br> ><br> > ----------------------------------------------<br> ><br> > #!/bin/bash<br> ><br> ><br> > # Clean up.<br> ><br> > rm -f .sconsign.dblite<br> ><br> > rm -f file[12]<br> ><br> ><br> > echo<br> ><br> > echo "---- Iteration 1: file1 =3D 'good'"<br> ><br> > echo "good" > file1<br> ><br> > scons<br> ><br> > echo<br> ><br> ><br> > echo "File1"<br> ><br> > cat -n file1<br> ><br> ><br> > echo "File2"<br> ><br> > cat -n file2<br> ><br> ><br> ><br> > echo<br> ><br> > echo "---- Iteration 2: file1 =3D 'bad'"<br> ><br> > echo "bad" > file1<br> ><br> > cat -n file1<br> ><br> > scons<br> ><br> > echo<br> ><br> ><br> > echo "File1"<br> ><br> > cat -n file1<br> ><br> ><br> > echo "File2"<br> ><br> > cat -n file2<br> ><br> ><br> > echo<br> ><br> > echo "---- Iteration 3: file1 =3D 'good'"<br> ><br> > echo "good" > file1<br> ><br> > cat -n file1<br> ><br> > scons<br> ><br> > echo<br> ><br> ><br> > echo "File1"<br> ><br> > cat -n file1<br> ><br> ><br> > echo "File2"<br> ><br> > cat -n file2<br> ><br> > ----------------------------------------------<br> ><br> ><br> ><br> > Run log:<br> ><br> > ----------------------------------------------<br> ><br> > $ ./run.sh<br> ><br> ><br> > ---- Iteration 1: file1 =3D 'good'<br> ><br> > scons: Reading SConscript files ...<br> ><br> > scons: done reading SConscript files.<br> ><br> > scons: Building targets ...<br> ><br> > ./command.sh file1 > file2<br> ><br> > scons: done building targets.<br> ><br> ><br> > File1<br> ><br> >=C2=A0 =C2=A0 =C2=A0 1 good<br> ><br> > File2<br> ><br> >=C2=A0 =C2=A0 =C2=A0 1 good<br> ><br> ><br> > ---- Iteration 2: file1 =3D 'bad'<br> ><br> >=C2=A0 =C2=A0 =C2=A0 1 bad<br> ><br> > scons: Reading SConscript files ...<br> ><br> > scons: done reading SConscript files.<br> ><br> > scons: Building targets ...<br> ><br> > ./command.sh file1 > file2<br> ><br> > scons: *** [file2] Error 1<br> ><br> > scons: building terminated because of errors.<br> ><br> ><br> > File1<br> ><br> >=C2=A0 =C2=A0 =C2=A0 1 bad<br> ><br> > File2<br> ><br> >=C2=A0 =C2=A0 =C2=A0 1 bad<br> ><br> ><br> > ---- Iteration 1: file1 =3D 'good'<br> ><br> >=C2=A0 =C2=A0 =C2=A0 1 good<br> ><br> > scons: Reading SConscript files ...<br> ><br> > scons: done reading SConscript files.<br> ><br> > scons: Building targets ...<br> ><br> > scons: `file2' is up to date.<br> ><br> > scons: done building targets.<br> ><br> ><br> > File1<br> ><br> >=C2=A0 =C2=A0 =C2=A0 1 good<br> ><br> > File2<br> ><br> >=C2=A0 =C2=A0 =C2=A0 1 bad<br> ><br> > ----------------------------------------------<br> ><br> > _______________________________________________<br> > Scons-users mailing list<br> > <a href=3D"mailto:[email protected]" target=3D"_blank">Scons-users= @scons.org</a><br> > <a href=3D"https://pairlist4.pair.net/mailman/listinfo/scons-users" re= l=3D"noreferrer" target=3D"_blank">https://pairlist4.pair.net/mailman/listi= nfo/scons-users</a><br> <br> <br> <br> -- <br> Keith Prussing<br> _______________________________________________<br> Scons-users mailing list<br> <a href=3D"mailto:[email protected]" target=3D"_blank">Scons-users@scon= s.org</a><br> <a href=3D"https://pairlist4.pair.net/mailman/listinfo/scons-users" rel=3D"= noreferrer" target=3D"_blank">https://pairlist4.pair.net/mailman/listinfo/s= cons-users</a><br> </blockquote></div> </blockquote></div> _______________________________________________<br> Scons-users mailing list<br> <a href=3D"mailto:[email protected]" target=3D"_blank">Scons-users@scon= s.org</a><br> <a href=3D"https://pairlist4.pair.net/mailman/listinfo/scons-users" rel=3D"= noreferrer" target=3D"_blank">https://pairlist4.pair.net/mailman/listinfo/s= cons-users</a><br> </blockquote></div> _______________________________________________<br> Scons-users mailing list<br> <a href=3D"mailto:[email protected]" target=3D"_blank">Scons-users@scon= s.org</a><br> <a href=3D"https://pairlist4.pair.net/mailman/listinfo/scons-users" rel=3D"= noreferrer" target=3D"_blank">https://pairlist4.pair.net/mailman/listinfo/s= cons-users</a><br> </blockquote></div> _______________________________________________<br> Scons-users mailing list<br> <a href=3D"mailto:[email protected]" target=3D"_blank">Scons-users@scon= s.org</a><br> <a href=3D"https://pairlist4.pair.net/mailman/listinfo/scons-users" rel=3D"= noreferrer" target=3D"_blank">https://pairlist4.pair.net/mailman/listinfo/s= cons-users</a><br> </blockquote></div> </blockquote></div> --000000000000edd6d6063a134768-- --===============3554158185219751703== Content-Type: text/plain; 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